CN115110373A

CN115110373A - Highway seal coat and road structure

Info

Publication number: CN115110373A
Application number: CN202210769390.3A
Authority: CN
Inventors: 李继光; 袁战文; 吴昊; 宋卫民; 温勇兵; 朱波
Original assignee: No2 Engineering Corp Ltd Of Cr20g; Central South University; China Railway 20th Bureau Group Corp; China Railway Construction Hunan Expressway Co Ltd
Current assignee: No2 Engineering Corp Ltd Of Cr20g; Central South University; China Railway 20th Bureau Group Corp; China Railway Construction Hunan Expressway Co Ltd
Priority date: 2022-07-01
Filing date: 2022-07-01
Publication date: 2022-09-27

Abstract

The invention relates to the technical field of road construction, in particular to a road seal and a road structure. According to the technical scheme, the first asphalt layer, the fiber layer, the second asphalt layer and the crushed stone layer are arranged, the fiber layer is arranged in the sealing layer structure, and the fiber layer is used for releasing the stress received and transmitted by the road surface layer in the using process, so that the technical problem that the service time limit of a road is influenced finally due to the fact that the reflection cracks are prevented from being generated by the road structure due to stress concentration on the basis that the stress is released is achieved through the fiber layer added in the sealing layer structure.

Description

Highway seal coat and road structure

Technical Field

The invention relates to the technical field of road construction, in particular to a road seal and a road structure.

Background

At present, according to the disease investigation result of the trunk road in China, the neglect of the treatment of the interlayer bonding position of the base layer during the design of a typical semi-rigid base asphalt pavement structure and the neglect of the lower sealing material and quality control during construction are found to be one of the important reasons for poor performance, serious early disease and short service life of part of trunk roads; when the sealing layer structure in the related art is used, the service time limit of a road cannot be guaranteed.

Disclosure of Invention

The invention mainly aims to provide a highway sealing layer and a road structure, and aims to solve the technical problem that the service time limit of a road cannot be guaranteed when a sealing layer structure in the related technology is used.

In order to achieve the above object, according to a first aspect of the embodiments of the present disclosure, the present invention provides a road sealing layer, which includes a first asphalt layer, a fiber layer, a second asphalt layer, and a crushed stone layer, which are sequentially formed from bottom to top.

Optionally, the first asphalt layer and the second asphalt layer are made of any one of SBS modified asphalt, emulsified asphalt and rubber asphalt.

Optionally, when the first asphalt layer is made of the SBS modified asphalt, the amount of the SBS modified asphalt per square meter is 1.1 kg to 1.8 kg;

when the first asphalt layer is made from the emulsified asphalt, the amount of the emulsified asphalt used is 1.6 kilograms to 2.2 kilograms per square meter.

Optionally, when the second asphalt layer is made of the SBS modified asphalt, the consumption of the SBS modified asphalt per square meter is 1.1 kg to 1.8 kg;

when the second asphalt layer is made from the emulsified asphalt, the amount of the emulsified asphalt used is 1.6 kilograms to 2.2 kilograms per square meter.

Optionally, the amount of the SBS modified asphalt used per square meter is 1.1 kg to 2.1 kg; alternatively, the first and second electrodes may be,

the amount of emulsified bitumen used was 1.6kg per square meter and 2.5 kg per square meter.

Optionally, the fiber layer is made of glass fiber or basalt fiber.

Optionally, the length of the glass fiber or basalt fiber is 30mm-120 mm.

Optionally, when the road sealing layer is applied to a water-stable sealing layer, the particle size of the crushed stone for forming the crushed stone layer is 4.75mm-13.2 mm;

alternatively, the first and second electrodes may be,

when the road sealing layer is applied to a bridge deck, the particle size of the broken stone for forming the broken stone layer is less than or equal to 9.5 mm.

Optionally, the thickness of the crushed stone layer is 0.8cm-1.3 cm.

According to a second aspect of the disclosed embodiment of the present invention, the present invention further provides a road structure comprising the road sealing layer of the first aspect.

According to the technical scheme, the first asphalt layer, the fiber layer, the second asphalt layer and the crushed stone layer are arranged, the fiber layer is arranged in the sealing layer structure, and the fiber layer is used for releasing the stress received and transmitted by the road surface layer in the using process, so that the technical problem that the service time limit of a road is influenced finally due to the fact that the reflection cracks are prevented from being generated by the road structure due to stress concentration on the basis that the stress is released is achieved through the fiber layer added in the sealing layer structure.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the structures shown in the drawings without creative efforts.

FIG. 1 is a schematic structural view of an exemplary pavement sealing of the present invention;

FIG. 2 is a schematic view of an interlayer structure of the exemplary seal structure of FIG. 1;

FIG. 3 is a graph showing the results of a tensile strength test of an exemplary fiber-asphalt composite of the present invention;

in FIG. 4, (a) is a tensile strength test result showing the effect of the amount of the modified emulsified asphalt on the tensile strength; (b) the test result of the influence of the fiber dosage on the tensile strength is shown; (c) the test result of the influence of the fiber length on the tensile strength is shown;

in FIG. 5, (a) shows the test results of the effect of the amount of SBS modified asphalt on the tensile strength; (b) the test result of the influence of the fiber dosage on the tensile strength is shown; (c) the test result of the influence of the fiber length on the tensile strength is shown;

FIG. 6 is a graphical representation of the tensile strength of an exemplary group of modified emulsified bitumens according to the present disclosure;

FIG. 7 is a graphical representation of the tensile strength of an exemplary SBS modified asphalt lot of the present invention;

FIG. 8 is a schematic diagram of the fracture energy of an example of the present invention;

FIG. 9 is a schematic diagram of the fracture energy of a modified emulsified asphalt SCB test piece according to an example of the present invention;

FIG. 10 is a schematic diagram of the fracture energy of an exemplary SBS modified asphalt SCB test piece of the present invention.

The reference numbers illustrate:

reference numerals	Name (R)	Reference numerals	Name (R)
				100	First asphalt layer	200	Fibrous layer
300	Second asphalt layer	400	Crushed stone layer

The objects, features and advantages of the present invention will be further explained with reference to the accompanying drawings.

Detailed Description

The technical solutions in the embodiments of the present invention will be described clearly and completely with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

It should be noted that all the directional indicators (such as upper, lower, left, right, front, and rear highway barriers and roads) in the embodiment of the present invention are only used to explain the relative position relationship between the components, the motion situation, etc. in a specific posture (as shown in the drawing), and if the specific posture is changed, the directional indicator is changed accordingly.

In the present invention, unless otherwise expressly stated or limited, the terms "connected," "secured," and the like are to be construed broadly, and for example, "secured" may be a fixed connection, a removable connection, or an integral part; can be mechanically or electrically connected; they may be directly connected or indirectly connected through intervening media, or they may be connected internally or in any other suitable relationship, unless expressly stated otherwise. The specific meanings of the above terms in the present invention can be understood by those skilled in the art according to specific situations.

In addition, if there is a description of "first", "second", etc. in an embodiment of the present invention, the description of "first", "second", etc. is for descriptive purposes only and is not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of the feature. In addition, the meaning of "and/or" appearing throughout includes three juxtapositions, exemplified by "A and/or B" including either A or B or both A and B. In addition, technical solutions between various embodiments may be combined with each other, but must be realized by a person skilled in the art, and when the technical solutions are contradictory or cannot be realized, such a combination should not be considered to exist, and is not within the protection scope of the present invention.

The inventive concept of the present invention will be further elucidated below in connection with some specific embodiments.

The invention provides a highway sealing layer and a road structure.

In an embodiment of the present invention, referring to fig. 1 to 2, the road sealing layer includes a first asphalt layer 100, a fiber layer 200, a second asphalt layer 300, and a gravel layer 400 sequentially formed from bottom to top.

In this embodiment, neglect of treatment of bonding between base course layers in designing a typical semi-rigid base asphalt pavement structure and neglect of lower cover material and quality control in construction when performing secondary construction or building a new road are one of the important reasons for poor performance, serious early diseases and short service life of part of trunk roads. The stress absorption layer with the stress absorption function is arranged between the semi-rigid base layer and the asphalt surface layer, and the stress absorption layer is an effective way for inhibiting the reflection cracks of the pavement and improving the adhesion between pavement layers. Through the seal design between the upper base layer and the lower surface layer, the bonding effect between the base layer and the surface layer can be improved, the generation of interlayer diseases is reduced, and on the other hand, the water resistance and the shearing resistance between the layers can be improved, so that the base layer material is effectively protected. However, the conventional technologies such as simultaneous chip seal and slurry seal cannot provide the long-term effective effects of suppressing reflection cracking, water resistance and adhesion due to inherent problems in durability, ductility, crack resistance, fatigue resistance and the like of the material itself.

Therefore, according to the technical scheme of the invention, the first asphalt layer 100, the fiber layer 200, the second asphalt layer 300 and the crushed stone layer 400 are arranged, the fiber layer 200 is arranged in the seal layer structure, and the fiber layer 200 is used for releasing the stress received and transmitted by the pavement layer in the use process, so that the technical problem that the service life of the road is influenced finally due to the fact that the reflection cracks are generated by the road structure due to stress concentration on the basis of releasing the stress is solved through the fiber layer 200 added in the seal layer structure.

It should be noted that, in this embodiment, when performing the road sealing construction, the layered construction of each layer of the fiber asphalt macadam flexible sealing structure may be adopted, specifically, after completing the construction of one layer in the construction area, the construction of the next layer is performed. And equipment such as a spreading vehicle and the like can be adopted for synchronous construction, and a fiber asphalt macadam flexible seal structure is formed in the construction area after a construction cycle is definitely completed. In this embodiment, the reflective crack of example means that, because there is a joint seam with the next layer or substructure that seal is adjacent, after the whole construction of road is accomplished, this joint seam is under the combined action of road self gravity or the load that the road bore, stress concentration can appear in joint seam department, concentrated stress can appear expanding in the seal structure under long-term effect, because seal structure among the correlation technique can not carry out effective release to the stress of this type of stress and upper portion load transmission, and then just can make seal structure appear damaging and finally form the crack. Such cracks can ultimately lead directly to damage to the entire road structure under the long-term effects of stress.

In some embodiments, referring to fig. 1 and 2, the first asphalt layer 100 and the second asphalt layer 300 are made of any one of SBS modified asphalt, emulsified asphalt, and rubber asphalt.

In this embodiment, a construction area is first defined on the finished cement base course or deck, the length of the construction area is preferably 200 meters, and the width of the construction area is preferably no wider than 3.6 meters. After the construction area is determined, asphalt is sprayed on the construction area. It can be clear that the asphalt sprayed on the first asphalt layer 100 can be SBS modified asphalt or emulsified asphalt, when the sprayed asphalt is SBS modified asphalt, the amount of the asphalt sprayed per square meter is 1.1 kg to 1.8kg, and when the sprayed asphalt is emulsified asphalt, the amount of the asphalt sprayed per square meter is 1.6kg to 2.2 kg.

It should be particularly and specifically noted that in this embodiment, the first asphalt layer 100 is preferably made of SBS modified asphalt, and the amount of SBS modified asphalt is determined through experiments, and the amount of asphalt sprayed per square meter is 1.1 kg to 1.8kg, so that the upper two layers of asphalt can achieve good coverage effect, and no later road surface flooding is caused by excessive asphalt consumption. The modified emulsified asphalt has better fluidity and permeability, so the dosage is more.

In addition, it should be emphasized that, in this embodiment, the spraying manner of the asphalt mainly adopts the prior art, the spraying manner of the asphalt may be but not limited to manual spraying or automatic spraying vehicle information spraying, and the like, and this embodiment only needs to spray the asphalt in the construction area, and does not involve improvement or design of the equipment for spraying the asphalt and the spraying manner, and therefore, the manner of spraying the asphalt is not described in detail herein.

In some embodiments, when the first asphalt layer 100 is made from SBS modified asphalt, the amount of SBS modified asphalt used is from 1.1 kg per square meter to 1.8kg per square meter; when the first asphalt layer 100 is made from emulsified asphalt, the amount of emulsified asphalt used is 1.6 kilograms to 2.2 kilograms per square meter.

In some embodiments, referring to fig. 1 and 2, when the second asphalt layer 300 is made from SBS modified asphalt, the amount of SBS modified asphalt used is from 1.1 kg per square meter to 1.8kg per square meter; when the second asphalt layer 300 is made from emulsified asphalt, the amount of emulsified asphalt used is 1.6 kilograms to 2.2 kilograms per square meter.

The asphalt sprayed on the second asphalt layer 300 can be SBS modified asphalt or emulsified asphalt, when the sprayed asphalt is SBS modified asphalt, the amount of asphalt sprayed per square meter is 1.1 kg to 1.8kg, and when the sprayed asphalt is emulsified asphalt, the amount of asphalt sprayed per square meter is 1.6kg to 2.2 kg.

In some embodiments, the amount of SBS modified asphalt used is from 1.1 kg to 2.1 kg per square meter; alternatively, the amount of emulsified bitumen used is 1.6kg per square metre, and 2.5 kg per square metre.

In this embodiment, when the environment of the structure exemplified by the present invention is a cold area, a perennial low-temperature area (such as permafrost areas in the Qinghai-Tibet plateau and within the polar circles from north to south), and an area with high drought and wind sand (such as the gobi area in the desert), the amount of the SBS modified asphalt used per square meter may be adjusted to 1.1 kg to 2.1 kg, or the amount of the emulsified asphalt used per square meter may be adjusted to 1.6kg to 2.5 kg. The use amount of the asphalt is adjusted, so that the influence of the use environment of the example on the seal structure of the example can be solved in the implementation process of the invention, and the use time limit of the seal structure of the example can be ensured.

In some embodiments, referring to fig. 2, the fiber layer 200 is made of glass fibers or basalt fibers. The length of the glass fiber or the basalt fiber is 30mm-120 mm.

After the first asphalt layer 100 is formed, the fiber layer 200 is formed, and it is preferable to form the fiber layer 200 by using 30mm to 60mm glass fiber or basalt fiber. In this embodiment, the boron-free and fluorine-free modified glass fiber is preferably used, which is less harmful to the environment and the health of the human body. Meanwhile, the length of the fiber should be greater than 40mm and not greater than 60 mm.

The fiber dosage is determined by tests to be better, the fiber can play a better anti-cracking effect in the range, and the condition that asphalt cannot wrap and cover all the fibers due to excessive fiber is avoided.

In some embodiments, referring to fig. 1 and 2, when the road sealing layer is applied as a water-stable sealing layer, the crushed stones used to form the crushed stone layer 400 have a particle size of 4.75mm to 13.2 mm; when the road seal is applied to the bridge deck, the crushed stones used to form the crushed stone layer 400 have a particle size of 9.5mm or less.

In this embodiment, the particle size of the crushed stone used for the crushed stone layer 400 needs to be determined according to the specific position of the construction area. It can be further specifically stated that when the construction is carried out on a water-stable sealing layer, the particle size of the crushed stone is preferably 4.75-9.5 mm and 9.5-13.2 mm, and when the construction is applied to a bridge floor waterproof sealing layer, the particle size of the crushed stone is preferably 0-4.75 mm or 4.75-9.5 mm; and, the thickness of the crushed stone layer 400 should be controlled within a range of 0.8cm to 1.3 cm.

In this embodiment, the aggregate of the seal layer on the water-stable layer has a particle size of 4.75-9.5 mm and 9.5-13.2 mm, and the aggregate of the waterproof bonding layer on the bridge deck has a smaller particle size because the middle layer and the upper layer of the asphalt pavement are directly on the waterproof bonding layer on the bridge deck, and there is no lower layer. The sealing layer on the water-stable layer is the lower layer for paving the asphalt pavement, so the aggregate has larger grain size.

In some embodiments, the crushed stone layer 400 has a thickness of 0.8cm to 1.3 cm.

In this embodiment, the thickness of the crushed stone layer 400 is set to be 0.8cm to 1.3cm, so that the overall strength of the whole sealing structure can be ensured in the implementation process of the invention, and the service life of the sealing structure is assisted to be improved.

Based on the same inventive concept, the invention also provides a road structure comprising the road sealing layer of the first aspect.

In some embodiments, please refer to fig. 3-10, in order to guide the construction and quality control of the fiber asphalt macadam seal and ensure the quality of the seal of the asphalt pavement structure and the interlayer treatment engineering, according to the current application situation of the asphalt pavement seal and interlayer treatment technology in China, a compiling group consults a large amount of relevant literature data of the asphalt pavement seal and interlayer treatment at home and abroad through extensive investigation and research, and establishes a fiber asphalt macadam flexible seal construction method, which is hereinafter referred to as a construction method, on the basis of the research result of a test road. It should be specifically and clearly noted that the fiber asphalt macadam seal or the fiber asphalt macadam flexible seal exemplified in the present embodiment refers to the road seal described in the previous exemplary embodiments of the present application.

On the basis of domestic and foreign research results, the construction method comprehensively considers the promotion effect of new materials and new technologies on the highway construction and maintenance development in China, adopts the fiber reinforced asphalt macadam flexible material as the pavement lower sealing layer, and has the effect of a stress absorption functional layer. The construction method can provide technical support for developing high-performance pavement interlayer functional materials and structures, perfecting interlayer treatment methods and quality control standards of semi-rigid asphalt pavements, composite asphalt pavements and old road reconstruction.

The fiber asphalt macadam flexible seal is an asphalt pavement seal and interlayer treatment method improved based on the traditional macadam seal, and is a new process for forming a flexible seal or a stress absorption interlayer by spreading a certain amount of asphalt binder, fibers and control graded macadam through a high-precision control method by using mechanical equipment such as a synchronous fiber macadam seal vehicle and the like and rolling by a road roller.

When the fiber asphalt macadam flexible seal is constructed, a layer of asphalt binder (modified asphalt or modified emulsified asphalt) is firstly spread by synchronous spraying (spreading) equipment, a layer of multi-dimensional disorderly distributed fibers is spread at the same time, a layer of asphalt binder is spread to cover and wrap the fibers as much as possible, a layer of macadam is spread finally, a rubber wheel rolling machine is used for rolling, and a composite flexible seal structure is formed after cooling.

The fiber asphalt macadam flexible lower seal layer is cut into fibers with certain length through a special process, the fibers are distributed in three-dimensional disorderly directions in the upper asphalt binder and the lower asphalt binder and are mutually lapped, a network winding structure is formed by the fibers and the asphalt binders, the fiber asphalt macadam flexible lower seal layer is similar to a flexible protective net with high elasticity, high strength and high toughness, and the comprehensive mechanical properties of the macadam seal layer, such as tensile property, shear resistance, compression resistance, impact resistance and the like, can be effectively improved.

Two-layer pitch binder's continuous unrestrained cloth has improved the waterproof nature of seal more, and the fibre that plays muscle and bridging effect in composite construction plays extremely strong adsorption to two-layer pitch binder in front and back in addition, and it can adsorb the oil content in the pitch very easily, increases the bond strength of seal.

The sealing agent is applied to the upper sealing layer of the asphalt concrete pavement, can better seal the tortoise-net crack of the original pavement, improve the waterproof performance of the original pavement, recover or improve the service function of the original pavement and delay the overhaul period of the original pavement.

The stress absorbing functional layer is applied to an under-sealing layer or a stress absorbing functional layer of the asphalt pavement, has good stress absorbing and dispersing capacity and waterproof performance, can absorb and disperse the reflection stress of the original cracks or the roadbed of the asphalt pavement, eliminates the stress concentration generated at the tips of the cracks of the old asphalt pavement, and effectively inhibits the occurrence of the reflection cracks.

The special fiber asphalt macadam seal coat vehicle can realize that the spreading of two layers of asphalt binders and the spreading of one layer of fiber and one layer of macadam can be finished on one device simultaneously, and is convenient and fast to construct, high in construction mechanization degree and stable in performance.

The fiber asphalt macadam seal can be divided into an upper seal (namely a surface wearing layer) and a lower seal (also can be used as a stress absorbing layer) according to the application layer and the function of the fiber asphalt macadam seal. The fiber asphalt macadam seal coat can be used as a surface wearing coat in the preventive maintenance or middle repair engineering of an asphalt pavement, can also be used as a lower seal coat or a stress absorption functional layer for newly-built semi-rigid base asphalt pavements and old road reconstruction, and can also be applied to a waterproof layer for bridge deck pavement.

The fiber asphalt macadam flexible seal is a composite sandwich-type flexible cushion layer, high-performance fibers with certain lengths are cut into an upper asphalt binder and a lower asphalt binder through a special process and are uniformly distributed in a three-dimensional disorderly direction and mutually overlapped, a network winding structure is formed by the high-performance fibers and the asphalt binders, and the high-performance fibers are similar to a flexible protective net with high elasticity, high strength and high toughness, so that the comprehensive mechanical properties of the macadam seal, such as tensile property, shear resistance, compression resistance, impact resistance and the like, can be effectively improved.

The fiber asphalt macadam flexible seal layer has a unique composite material network structure and comprehensive mechanical properties, and under the condition of repeated temperature change, the fiber asphalt macadam flexible seal layer has high toughness and extensibility due to the material, and the tensile strength and the deformation resistance of the fiber asphalt macadam flexible seal layer are far greater than the shrinkage tensile stress or tensile strain caused by temperature change, so that the crack resistance of a pavement structure is improved, and low-temperature shrinkage cracks of an asphalt pavement and reflection cracks caused by repeated temperature change can be effectively inhibited.

Construction preparation: construction is carried out according to the relevant requirements of technical Specification for construction of asphalt road surfaces for roads (JTGF 40); besides meeting the relevant regulations of the construction method, the raw materials used also meet the relevant requirements of technical Specifications for construction of asphalt road surfaces for roads (JTGF 40).

Preparation before construction: before construction, raw material detection reports, asphalt, gravel and fiber spreading amount must be provided and the requirements are confirmed. The construction machines are checked and calibrated before construction, and the construction machines are matched and combined reasonably, safely and effectively. And setting out the checked and qualified road surface, determining a construction scheme, and preparing the machinery and materials for construction.

And (3) carrying out lower bearing layer treatment: before construction, mechanical property indexes of a lower bearing layer of the fiber asphalt macadam seal coat are detected, necessary guarantee is provided for the construction of the seal coat, and indexes such as flatness and compactness of the seal coat need to be measured. When the value of a certain item does not reach the standard, measures should be taken in time for processing. After all indexes of the lower bearing layer meet the requirements, the lower bearing layer is cleaned, and professional equipment such as a sprinkler, a blower, a sweeper and the like can be selected to clean according to the field condition, so that the surface of the lower bearing layer is clean.

The construction guide line is arranged: taking the center line of the original pavement as a construction center line, and covering the inner side of the side line by the coir rope to shield broken stones for construction. And (3) paving the asphalt felts at the starting point and the end point of the construction to ensure the starting point and the end point to be neat and beautiful and avoid polluting the road surface outside the construction area.

Detection and preparation of raw materials: before construction, raw material detection reports, asphalt, gravel and fiber spreading amount must be provided and the requirements are confirmed. The quality inspection of the materials before construction is carried out in batches of crushed stones, asphalt, fibers and the like with the same specification and variety from the same material source and the same batch to a production site. The detection items and requirements of the materials are in accordance with the corresponding raw materials and performance requirements in the method. The asphalt binder is preheated in advance, and is required to be insulated according to construction requirements after being added into sealing equipment, and construction can be carried out after the asphalt binder meets the requirements of material temperature.

The synchronous vehicle sequentially sprays (scatters) the materials: and spraying a first layer of asphalt by using the fiber asphalt macadam seal all-in-one machine, synchronously spreading a layer of fiber, spraying a second layer of asphalt, and spreading a layer of macadam. The uniformity should be guaranteed when the cloth is sprayed (spread), measures must be taken when starting and stopping, excessive or too little spraying is avoided, the width of the transverse lap joint should be adjusted, the phenomenon of excessive or missed spraying at the lap joint is avoided, and the vehicle speed is preferably controlled to be 3-4.5 km/h.

During construction, attention should be paid to joint treatment, and the joint treatment is specifically divided into a transverse joint and a longitudinal joint. At the position of the transverse joint, the joint is closely connected with the previous construction during the second construction, and meanwhile, the joint is prevented from being overlapped with the section of the previous construction. Therefore, before each spreading (scattering) process, the spread road section is covered by a felt, a sheet iron or a gunny bag, so as to avoid the overlapping of sealing layers when the spreading (scattering) process is carried out again. The areas which are not well sprinkled (spread) should be treated in time to ensure even sprinkling (spreading). If the modified emulsified asphalt is used as the asphalt binder, the gravel spreading should be completed before the modified emulsified asphalt is demulsified.

Manual repair and inspection: when local defect appears in the flexible seal coat of fibre pitch rubble shop-laying in-process, in time carry out artifical repair, the focus of artifical repair is: the local crushed stones are not spread or the spreading amount is too large, and the manual work is needed to spread the crushed stones evenly and sweep away the redundant crushed stones; after the rolling is completed, the surface of the seal layer needs to be manually inspected, cleaned and removed. This is conditionally facilitated by the use of dedicated cleaning equipment.

Rolling by using a rubber wheel: after the spreading (spreading) is finished, immediately rolling the tyre road roller with more than 16T along the running direction for at least 2 times, wherein the initial pressing speed is not more than 2km/h, the re-pressing speed is coordinated with the speed of the sealing layer vehicle and is controlled to be about 3.5 km/h. If the construction is carried out in a framing manner, the lap seam is processed. The first frame of the two overlapped parts is kept for 5-10 cm in width without spreading broken stones, and the second frame is spread along the edge of the reserved asphalt.

Field detection and acceptance: after the rolling is finished, carrying out detection and approval work after the modified asphalt is cooled or the modified emulsified asphalt is demulsified and reaches a certain strength, summarizing and reporting the detection results, and waiting for acceptance work.

Paving a surface layer: after the field detection and acceptance work of the fiber asphalt macadam seal coat is finished, the surface layer construction can be carried out.

Construction attention: the requirements of the fiber gravel seal on weather conditions are strict, and the ideal weather conditions are sufficient sunlight, high temperature, low humidity, weak wind or no wind, rain and fog. Wherein the lowest temperature condition is that the air temperature is higher than 15 ℃, the pavement temperature is higher than 20 ℃ and the temperature is in the rising trend; when the temperature is lower than 20 ℃, the pavement temperature is lower than 25 ℃ and the pavement temperature is in a descending trend, the construction cannot be carried out; when the temperature is higher than 45 ℃ and the temperature of the road surface is higher than 60 ℃, the construction is not suitable. During construction, the temperature of the road surface under tree shade or other shady places should be taken into consideration to ensure that the requirements are met. The original road surface is carefully cleaned before sealing, and a sufficient number of rubber-wheel road rollers are ensured in the operation process so as to complete the rolling and positioning procedures in time before the asphalt temperature is reduced or after the emulsified asphalt is demulsified. The oil nozzle height of synchronous seal car is different, and the thickness of the pitch membrane that forms can be different (because the fan-shaped vaporific pitch of each nozzle spun overlaps the condition differently), makes the thickness of pitch membrane accord with the requirement through adjustment nozzle height. The synchronous layer-sealing vehicle should run uniformly at a proper speed, and the spreading (spreading) rates of the asphalt binder and the stone must be matched with each other under the premise. For places with linear changes such as curves, the synchronous layer sealing vehicle is in an inclined state, and the oil pressure on the side with the oil injection pipe at a high position is insufficient, so that insufficient spraying can be caused; particularly on long longitudinal slope sections, the rock extrusion force may cause excessive spreading. Therefore, for these special road sections, if the mechanical construction work is not in place, manual sprinkling or removal of excess gravel or asphalt is used. When longitudinal and transverse seams appear, materials such as felt, iron sheet or gunny bag should be laid on the scattered road surface to prevent the oil from overlapping. The test section is selected from a typical section, the length of which is generally not less than 200m, and the test section is preferably selected from a straight section of the main line. After the test section is selected, the prepared machinery and materials are transported to the construction section site, and inspection before construction is performed. According to design parameters and various preset technical requirements, such as: and paving the test section according to the asphalt spreading amount, the gravel spreading amount, the height of the spraying pipe, the gravel spreading height, the opening degree and the temperature of each valve, the running speed of the synchronous gravel truck, the matching conditions of matched machines and machinery and the like.

The detection method and standard of the material spreading amount are as follows: selecting a cross section, placing two 0.6m multiplied by 0.4m tarpaulins or trays at trisection points, weighing the increased mass after the asphalt is sprayed on a sealing vehicle, wherein the average value of three samples is the sampling test result of the asphalt amount at one time, and the grade difference of the three samples is not more than 0.3 kg/square meter. Detecting frequency: the asphalt, fiber and broken stone are sprayed (scattered) once per 1000 square meters on site. And the integration effect of each parameter, technical requirement and various mechanical equipment is determined through paving and adjusting the test section, and standard and ordered construction is carried out to ensure the construction quality.

Temperature control during construction: if the modified asphalt is adopted, the heating temperature of the modified asphalt is controlled between 190 ℃ and 200 ℃, and the spraying temperature is controlled between 180 ℃ and 195 ℃. The heating temperature of the crushed stone is controlled to be about 90 ℃, the spreading temperature is controlled to be above 60 ℃, and the heat preservation is carried out by a heat preservation system carried by a sealing vehicle during the construction period. If the modified emulsified asphalt is adopted, the heating temperature of the modified emulsified asphalt is controlled to be between 50 and 70 ℃, and the spraying temperature is controlled to be between 50 and 70 ℃. The heating temperature of the macadam is controlled between 60 ℃ and 70 ℃, the spreading temperature is controlled between 60 ℃ and 70 ℃, and the heat preservation is carried out by a heat preservation system of the sealing vehicle during the construction period. If the rubber asphalt is adopted, the heating temperature of the rubber asphalt is controlled to be 195-205 ℃ due to high viscosity, the spreading temperature is controlled to be 190-200 ℃, and the heat preservation is carried out by the heat preservation system of the sealing vehicle during construction.

Designing the construction length and width: the construction length is not less than 200m (usually 200-400 m), and the designed width of the pavement is used as a construction control unit. When the asphalt macadam synchronous spreading vehicle is used for operation, the construction width is controlled within 3.6 meters. Construction is carried out along the dimension sideline of lofting, and the spreader is ensured to be straight and beautiful in paving effect in the construction process. The spreading thickness of the asphalt should be strictly controlled, and the spraying amount of the asphalt is controlled according to the optimal mixing ratio; the spreading amount of the crushed stones and the fibers is strictly controlled, so that the uniform thickness of the crushed stones, tight and compact embedding of the particles, uniform spreading of the fibers, and no agglomeration and segregation phenomena are ensured.

After the spreading (spreading), rolling and manually removing the redundant broken stones. After construction is finished, the road section needs to be sealed for 1-3 hours, and then proper maintenance work is carried out, so that the process is ensured to be correct.

And after the construction of the test road section is finished, carrying out field quality detection, determining a subsequent large-area construction scheme according to a field test result, and carrying out large-scale production preparation work. The construction scheme and the determined construction process obtained through the test section are used as formal construction basis after being approved by a manager and an owner, the construction project is not allowed to be changed randomly, and the construction scheme and the determined construction process are approved by the manager or the owner when the construction scheme and the determined construction process need to be changed.

Crushing stone: the technical requirements of the macadam used for the fiber asphalt macadam seal are basically the same as those of the stone used for the asphalt mixture. The crushed stone is clean, weatherproof, free of impurities, and has sufficient strength and abrasion resistance. Neutral and alkaline stone materials such as basalt, limestone, diabase and the like are preferably selected; strong alkaline stones should be carefully selected, and acidic stones such as marble, quartzite and the like are generally not considered. Diabase, basalt and the like are preferably selected in rainy and humid areas, limestone soaked by water is not required, and the ultimate compressive strength of the limestone is reduced. The crushed stone is graded in single grade (single grain size), wherein the content of stone powder and soil impurities is not more than 1%. Aggregate with good edge and corner properties is used as much as possible, and a needle sheet-shaped structure is avoided, so that the aggregate can reach proper embedding depth and bonding effect in the asphalt. The specification and lithology of the broken stones can be determined by comprehensively considering the conditions such as pavement conditions, traffic loads, seal thickness, application layer positions and the like. Large-particle-size stones are removed through screening in construction, blocking of blanking holes of a gravel seal vehicle is prevented, and the phenomena of oil zones and no stones are avoided. When the waterproof sealing layer is used as a lower sealing layer, the particle size of the crushed stone is preferably 4.75-9.5 mm and 9.5-13.2 mm, and when the waterproof sealing layer is applied to a bridge floor, the particle size of the crushed stone is preferably 0-4.75 mm or 4.75-9.5 mm.

Each index of the macadam is required to meet the relevant regulations of the existing standard, namely, the road engineering aggregate test specification (JTGE42-2005) and the road engineering asphalt and asphalt mixture test specification (JTGE 20-2011). Specific performance requirements are shown in table 1.

TABLE 1 technical Performance test indexes for crushed stones

An asphalt binder: according to the engineering practice, the fiber asphalt macadam flexible seal coat can adopt modified emulsified asphalt, modified asphalt or rubber asphalt as an asphalt binder. The specific selection is determined by comprehensively considering the conditions such as traffic load, weather conditions, seal layer thickness and position, local engineering experience and the like. The technical requirements of the asphalt binder are in accordance with the relevant regulations of technical Specifications for construction of asphalt road surfaces for roads (JTGF 40).

Modified emulsified asphalt: the fiber macadam seal coat can adopt modified emulsified asphalt with good performance, and preferably adopts SBS modified emulsified asphalt, and the dosage of SBS modifier is not less than 3%. The modified emulsified asphalt must have sufficient bonding performance to ensure the bonding effect between the asphalt and the crushed stone. Meanwhile, under the condition of meeting the spreading amount of a unit area, the modified emulsified asphalt must have certain fluidity, but cannot flow before spreading the crushed stones, so that the embedding depth of the crushed stones in the asphalt is ensured, and the falling of the crushed stones is reduced.

The demulsification speed of the modified emulsified asphalt is changed along with the difference of construction time and seasons, the demulsification time of the modified emulsified asphalt is adjusted according to climatological conditions, and the selection and the dosage of the emulsifier and the additive are also properly adjusted. Specific technical requirements for modifying the emulsified asphalt are shown in table 2.

TABLE 2 modified emulsified asphalt specifications

Modified asphalt: for fiber asphalt macadam seal coat with higher technical requirements or when construction weather conditions are limited, SBS modified asphalt is adopted as an asphalt binder. The modified asphalt except the matrix asphalt should meet the regulations of technical Specifications for road asphalt pavement construction (JTGF 40). The variety and the dosage of the modified asphalt modifier can be determined by referring to the past successful engineering experience, but the modified asphalt modifier must be determined by experimental verification and meets the technical requirements of modified asphalt in technical Specification for road asphalt pavement construction (JTGF 40). Specific technical requirements for modifying the bitumen are shown in table 3.

TABLE 3 technical requirements for modified bitumen

Technical index	Unit of	Performance requirements	Test method
				Penetration degree (25 ℃, 100g, 5s)	0.1mm	≥60	T0604
Penetration index PI	—	≥-0.2	T0604
				Ductility of 5 degrees and 5cm/min	cm	≥30	T0605
Softening point	℃	≥55	T0606
				Kinematic viscosity 135 deg.C	Pa·s	≤3	T0619
Flash Point (. degree.C.)	℃	≥230	T0611
				Solubility (%)	％	≥99	T0607

It should be noted that: for cold and perennial low-temperature areas or areas with large drought wind sand, the asphalt spreading amount can be properly increased by 0.2-0.3 kg/m3 according to engineering conditions; for rainy and cold areas, the modified emulsified asphalt is carefully selected; and for the road sections with hot summer and large traffic volume, the modified asphalt or the rubber asphalt is recommended to be selected.

Rubber asphalt: the rubber asphalt is rubber modified asphalt produced by reacting vulcanized rubber powder produced by processing waste tires with matrix asphalt at a high temperature through constant-temperature heating and stirring by using reaction equipment. The rubber asphalt has relatively high cost, but the fiber asphalt macadam seal constructed by the rubber asphalt has more excellent toughness, weather resistance, interlayer bonding performance and reflection crack resistance.

The rubber asphalt material should strictly meet the relevant regulations of technical Specifications for construction of road asphalt pavements (JTGF40), and the specific technical requirements are shown in Table 4.

TABLE 4 specification of rubber asphalts

Technical index	Unit of	Performance requirements	Detection method
				Penetration degree (25 ℃, 100g, 5s)	0.1mm	>40	T0604
Ductility (5cm/min, 5 ℃ C.)	cm	≥10	T0605
				Softening point	℃	≥65	T0606
Flash point (open)	℃	≥280	T0611
				Penetration index PI	—	＞0.0	T0604
Rotational viscosity at 180 ℃ of	Pa·s	2.0～4.0	T0625
				Elastic recovery of 25 deg.C	％	≥70	T0662

Fiber type: the fibers should have good cuttability, high breaking strength and oil absorption. Glass fiber, basalt fiber, etc. may be used. It is preferable to use glass fibers of the sprayed roving type, and preferably boron-free and fluorine-free modified glass fibers which are less environmentally harmful and harmless to the health of the body.

Fiber length: the cutting length of the fibers is comprehensively determined according to factors such as the application layer position of the fiber asphalt macadam seal, the type and the amount of the modified emulsified asphalt, the thickness of the fiber asphalt macadam seal, the amount of macadam, the type and the size of traffic, and the like, and is generally 30-120 mm. According to experience and test results, the fiber asphalt macadam seal coat prepared by the fibers of 40mm or 60mm has better effect.

The fiber dosage and technical indexes are as follows: 1. the average amount of the fibers is as follows: the dosage of the sealing agent is usually about 60 g/square meter when the sealing agent is used for sealing layers. The fiber amount is determined according to the condition of the road surface and the application type degree. The amount of the fibers used as the stress absorbing functional layer is suitably increased. The technical requirements of the glass fiber are in accordance with relevant regulations of reinforced product test method (GB/T9914) and reinforced material yarn test method (GB/T7690), and the technical performance detection items and technical requirements of the glass fiber are shown in Table 5.

TABLE 5 test items and technical requirements for technical properties of glass fibers

Detecting items	Unit of	Performance requirements	Ambient temperature	Relative humidity	Detection method
						Linear density of	tex	2400±120	(23±2)℃	(50±10)％	GB/T7690.1
Water content ratio	％	≤0.15	(23±2)℃	(50±10)％	GB/T9914.1
						Combustible content	％	1.20±0.15	(625±20)℃	—	GB/T9914.2
Stiffness of the sheet	mm	125±20	(23±2)℃	(50±10)％	GB/T7690.4

The design principle of the material mixing ratio is as follows: firstly, determining the types and characteristics of materials such as asphalt binder, broken stone and fiber according to engineering requirements, then, according to factors such as engineering purposes, road traffic volume, pavement structure design and construction seasons, adopting an empirical method as a main method, comprehensively determining the use amount of various materials by combining theories, and finally, carrying out necessary and reasonable adjustment according to test detection results or field construction conditions. Before construction, the spreading/spreading condition of the fiber asphalt macadam seal coat vehicle is calibrated according to the determined material consumption. Specifically, the material combination design follows the following principles: the raw materials are selected to meet the basic technical requirements and follow the sustainable development principle of local conditions, local materials, economy and environmental protection; all indexes of raw materials of the fiber asphalt macadam seal coat meet the quality requirements of relevant industrial standards; and systematically designing, verifying and adjusting the design according to the actual engineering characteristics, and finally determining the optimal material combination design. The mix proportion design takes the optimal combination of materials such as macadam, fiber, asphalt binder and the like as a target, and takes the interlayer bonding performance and the bonding performance of asphalt and macadam as design indexes; and paving a test road after the design of the mix proportion is finished, and adjusting the gravel distribution amount and the asphalt using amount according to the using effect of the test road.

Determination of material usage: spreading amount of broken stones: the amount of the gravel in the fiber asphalt gravel seal layer mainly depends on the thickness of the seal layer, the characteristics of gravel materials, the traffic volume of roads, the technical condition and the like. When the fiber asphalt macadam seal coat is used for a lower seal coat or a stress absorption layer, the usage amount of the macadam is required to ensure 60-80% of coverage rate (according to actual experience, the too low macadam coverage rate cannot achieve the effect of protecting the seal coat, and the too high coverage rate easily causes oil flooding during surface layer construction); when the fiber asphalt macadam seal is used for a surface wearing layer, the dosage of the macadam is required to ensure 100 percent of coverage rate.

The maximum thickness of the fiber asphalt macadam seal is generally considered to be equal to the maximum nominal particle size of macadam, and the thickness of the fiber asphalt macadam seal is usually 5-15 mm according to the particle size of the macadam. The range of the crushed stone distribution amount can be selected with reference to table 6.

TABLE 6 fibre asphalt macadam coat macadam spreading amount Range (kg/square meter)

The asphalt dosage is as follows: the dosage of the asphalt should first consider the type of the fiber asphalt macadam seal, the characteristics (type, particle size, shape, gradation, etc.) of the macadam aggregate, the dosage of the macadam aggregate, the type of asphalt, the content of asphalt, and other factors. The asphalt dosage ranges of the fiber asphalt macadam seal coat with the macadam particle size of 4.75-9.5 mm and 9.5-13.2 mm are respectively shown in the table 2 and the table 3. For the bridge deck waterproof seal, when the meter stone with the particle size of 0-4.75 mm is adopted, the using amount of asphalt is reduced by 0.2 kg/square meter on the basis of the using amount of the fiber asphalt macadam seal asphalt with macadam of 4.75-9.5 mm. The amount of the modified asphalt is usually adjusted according to the type and size of the traffic, the construction season (air temperature) and other factors. The use level of the modified asphalt is preferably reduced by 5 to 10 percent in heavy traffic or high traffic road sections; the use level of the modified asphalt in autumn construction is increased by about 5 percent compared with the use level of the modified asphalt in summer construction. When rubber asphalt is used, the amount of rubber asphalt may be referred to the amount of modified asphalt.

TABLE 7 Pitch dosage range of fiber pitch macadam seal coat pitch (kg/square meter) with macadam of 4.75-9.5 mm

TABLE 8 Pitch dosage range of fiber pitch macadam seal coat pitch (kg/square meter) with macadam of 9.5-13.2 mm

The fiber dosage is as follows: the fiber consumption should be properly adjusted according to the technical status of the original road surface, the traffic type and other factors. Based on experience and experimental results, values are preferably taken in the dosage ranges of Table 9.

Meter 9 dosage range of fibre macadam seal coat glass fibre (g/square meter)

The main matched construction equipment of the fiber asphalt macadam lower seal layer meets the following requirements:

sprinkling (spreading) equipment: preferably, a four-synchronous sealing vehicle is selected, and mainly comprises an asphalt heat-insulating tank, a pressurizing device, an adjustable asphalt nozzle, a fiber cutting and spreading structure and a gravel bin. The seal vehicle can simultaneously and continuously construct a layer of asphalt 1, a layer of fiber 1, a layer of asphalt 1 and a layer of crushed stone 1 to form an interactive compact network winding structure; a rapid heating device is arranged in the tank body, so that the preparation time before construction is shortened, and the distribution temperature of asphalt is ensured; a heat conduction oil interlayer is arranged in the asphalt pipeline, and a heat conduction oil circulating heating mode is adopted to ensure that the pipeline is smooth; the spraying system can automatically control the asphalt spreading amount and the fiber and gravel spreading amount along with the change of the vehicle speed, and ensure accurate and uniform spreading (spreading).

The seal car should meet the relevant performance indexes: the volume of the asphalt tank is not less than 8L, the volume of the fiber bin is not less than 5m3, the broken stone is not less than 10m3, the fiber cutting length is 30-120 cm, and the asphalt spreading amount is as follows: 0.2-3kg per square meter, and the spreading amount of the broken stones is as follows: 2-22L per square meter, and the fiber distribution amount: 30-120g per square meter. The spreading amount can be accurately controlled, the nozzles can be independently controlled to adjust the spreading width and the spraying amount, the spreading (spreading) amount is not influenced by the vehicle speed, and various spreading (spreading) operations can be completed in a cab.

The sealing construction should also be equipped with devices such as a tyre roller, a road sweeper, a powerful blower and the like.

Before construction, a metering system, a pipeline conveying system and the like of a construction vehicle are detected, so that accurate metering, smooth fiber spreading pipelines and uniform shearing are guaranteed. And (3) debugging equipment, respectively testing the spreading amount of asphalt, gravel and fibers, and determining construction parameters so as to meet the requirement of the construction consumption of the fiber asphalt gravel seal.

The quality control requirements are as follows: the construction quality standard of the fiber asphalt macadam flexible seal layer executes the regulation of technical Specification for construction of asphalt road surfaces for roads (JTGF 40).

Checking materials and equipment before construction: before construction, a detection report of raw materials and the spreading amount of asphalt, broken stone and fiber are provided, and the requirements are met; the construction machine must be inspected. After confirming that the materials, equipment and the like are not changed and meet the requirements, construction can be carried out. The quality inspection of the materials before construction is carried out by a batch of crushed stones, modified emulsified asphalt, fibers and the like of the same specification and variety from the same material source and in the same batch and transported to a production site. When the content of the evaporation residue of the modified emulsified asphalt or the water content of the crushed stone changes, the setting of the spreader must be adjusted, and the construction can be carried out after confirming the mix proportion of the materials and the designed mix proportion.

And (3) quality control in the construction process: before construction every day, the spraying nozzle and the fiber nozzle of the modified emulsified asphalt are ensured to be smooth, and whether the metering is consistent with the metering of a computer or not is checked by rechecking. Before spreading the gravels every day, the control quantity of the gravels is compared with the actual construction quantity to be adjusted, so as to achieve longitudinal uniformity and transverse balance. The phenomenon of more scattering, less scattering or leaking scattering is ensured not to occur. The construction material is counted once every 50000 square meters, and the deviation between the design material and the construction material is compared to control the spreading amount of the raw materials such as asphalt, fiber, broken stone and the like.

Sampling detection is carried out on the fiber asphalt macadam seal coat in the construction, and the items, the frequency, the allowed errors and the method of the sampling detection are shown in a table 11.

TABLE 11 inspection requirements for fiber chip sealer construction

Material detection before construction: the fiber asphalt macadam seal coat is used for detecting raw materials such as asphalt, macadam and fibers before construction, and can be used after detection indexes meet the technical requirements.

And (3) appearance inspection: the construction process is carried out at any time, the quality requirement is that the leakage (scattering) area does not exceed 0.1 percent of the total area, no accumulation exists, the distribution is uniform and consistent, the coating is scraped and observed by a hard object, the coating is firmly bonded with the surface of the base layer, no peeling occurs, and no oil pocket and base layer are exposed.

Asphalt spreading amount test: the storage bin of the seal car is fully preheated before the test, and the water temperature and the engine oil temperature reach specified values; the sealing layer vehicle works under the conditions of designing the maximum spreading amount and the minimum spreading amount respectively; test field: the test site is selected, typically a section of the test road section. Setting the height between the sprinkling pipe and the ground; test equipment: stopwatches, tachometers, tape measures, poles, balances, sampling plates (trays), and the like. The test method comprises the following steps: the sealing vehicle respectively sprays with the maximum set amount of spreading and the minimum set amount of spreading, and the sampling plate sets up 9, divides into three rows along violently left, middle, right symmetrical arrangement. And (4) actually evaluating the field construction effect, and further adjusting the spreading amount.

Fiber spreading test: a motion spreading operation is employed. The sealing vehicle moves forward at a constant speed in a certain test area, the spreading amount of the fibers is set to a certain value, the fibers are spread by an automatic system of equipment, the deviation between the actual spreading amount of the fibers and the set spreading amount in the automatic system is verified, and the spreading parameters are further adjusted if necessary.

Verification test of gravel distribution amount: the image method can be adopted to test the spreading amount and uniformity of the broken stones during construction.

And (3) testing waterproof and anti-permeability performance: the waterproof performance of the fiber asphalt macadam seal coat can be measured by adopting a water seepage meter, the detection frequency is 3 per 5000 square meters, and the water seepage coefficient is waterproof within 30min under the pressure of 60cm water column.

Field pull test (interlayer adhesion test): the bonding performance of the fiber asphalt macadam seal coat and the base layer can be detected and evaluated through a field drawing test. And 6 measuring points are taken on each test section, wherein 2 measuring points are taken on the road shoulder, 4 measuring points are taken on the traffic lane, the diameter of the test drawing section is 100mm, and the residual drawing strength of the test drawing section is detected. The test is carried out by adopting a pavement interlayer bonding performance tester. According to the national relevant regulations and regulations, the safety production management network for full-time security officers, team and concurrent security officers and site safety electricity utilization responsible persons to participate is formed by seriously following the policy of 'first safety and first prevention being the main' and combining the actual conditions of construction units and the specific characteristics of projects, the safety production responsibility system is executed, the responsibility of all levels of persons is determined, and the safety production of the projects is well grasped.

Setting of safety facilities: after the construction road section is determined, the construction vehicle is driven to 1600m in front of the construction point, a column notice board of 'construction 1600m in front' is arranged, the safety of personnel in the construction area is ensured, the construction area is sealed by a reflective cone cylinder, the construction area is gradually extended according to the construction requirement, and the total length is controlled within 1000 m.

The fiber asphalt macadam seal coat can adopt modified emulsified asphalt as an asphalt binder, and due to the characteristics of the modified emulsified asphalt, the fiber asphalt macadam seal coat shows good environmental benefits, which are mainly reflected in the following aspects: can be constructed in a cold state. Compared with the traditional hot asphalt, the modified emulsified asphalt can be constructed at normal temperature or even low temperature, the construction season is prolonged, and the weather conditions of all regions are different, so that the construction period can be prolonged by 2-4 months within one year. Meanwhile, the fiber asphalt macadam seal coat can be demulsified, coagulated and hardened in a short time, so that the technology can be constructed under the condition of not closing traffic. The energy consumption is reduced. When the modified emulsified asphalt is used as a binder, the modified emulsified asphalt can be stored, transported and used at normal temperature without being heated, and only when the modified emulsified asphalt is produced, the asphalt needs to be heated once. According to statistics, compared with the hot asphalt, the modified emulsified asphalt can save heat energy by more than 50%. And the environmental pollution is reduced. The modified emulsified asphalt can reduce environmental pollution to a great extent, the production process is in a closed system, the product is liquid at normal temperature, and the product is sprayed or mixed in a cold state during use, so that the energy consumption and the requirements on construction machinery and equipment are reduced, the discharge amount of harmful gas is reduced, and the construction environment is improved.

The fiber reinforced asphalt macadam flexible lower seal layer is feasible from the technical and economic aspects, and the economic and social benefits brought by the excellent performance and the function can be embodied in particular as follows: 1) the maintenance cost is saved, the economic benefit is remarkable, and the driving comfort level and the road service level are improved; 2) the matched construction process can improve the construction efficiency and ensure the construction quality; 3) reduce dust noise and environmental pollution. The application and popularization of the technology have positive promoting effect on the development of the road construction and maintenance career in China; 4) in addition, the research result of the project can also provide theoretical basis and technical support for developing high-performance pavement interlayer functional materials and structures, perfecting interlayer treatment methods and quality control standards of semi-rigid asphalt pavements and composite asphalt pavements in China, and has practical popularization value and application prospect.

The fiber-reinforced flexible asphalt macadam seal coat can effectively improve the crack resistance and durability of a pavement structure and delay the occurrence time of pavement diseases, so that the investment of maintenance cost can be reduced in the operation period. Therefore, the whole life cycle economy of the fiber reinforced asphalt macadam flexible seal and the traditional synchronous macadam seal is contrastively analyzed, so that the economic benefit is further highlighted. The life cycle cost for road works includes not only initial construction costs but also maintenance and repair costs and is closely related to the operation time.

Compared with the traditional synchronous chip seal technology, the fiber dispersing and spreading equipment is added on raw materials and a synchronous seal vehicle, other construction conditions are the same, and the construction efficiency and the construction complexity are not influenced. The matched construction process can improve the construction efficiency, and the construction quality can be better ensured through a standard construction control method. Although compared with the traditional sealing method, the fiber asphalt macadam flexible sealing layer has relatively high manufacturing cost, but has good stress dispersion and absorption capacity, reflection crack resistance, interlayer bonding performance and waterproof performance, can effectively improve the stress state between the layers of the pavement structure, inhibits the generation of diseases and prolongs the service life of the pavement. The method has more remarkable economic benefit from the viewpoint of the whole life cycle cost of the road surface.

The fiber asphalt macadam flexible seal layer (stress absorption functional layer) can well meet the requirements of high-performance and long-life pavement on the aspects of asphalt pavement maintenance, pavement reflection cracks and interlayer adhesion. Firstly, compared with the traditional interlayer treatment technology, the flexible sealing material has better mechanical property, stability and durability. Secondly, because the combination characteristic of the material is fully considered in the design and construction process, the modified asphalt is used as the substrate of the functional layer, the functional layer has strong bonding performance, and the base layer and the surface layer are better bonded together through the contact, the luster and the wrapping with high-performance and high-toughness short fibers and the winding effect on the broken stones, so that the flexible sealing layer can have the effect of 1+1>2 in the pavement structure through the mutual bonding and the embedding, extruding and meshing effects of the surface layer and the base layer. Therefore, the fiber asphalt macadam flexible seal coat is used for treating the semi-rigid base asphalt pavement and the composite pavement between layers, an ideal using effect can be achieved, the construction difficulty cannot be increased compared with a traditional method for treating between layers, and the fiber asphalt macadam flexible seal coat has a good application prospect.

At present, when the fiber asphalt macadam combination material is designed, the approximate application range of the raw material is mostly determined based on the prior experience, however, the crack resistance of the fiber asphalt macadam is influenced by a plurality of factors such as the fiber amount, the fiber length, the asphalt amount, the asphalt type and the like, and materials from different sources also have certain influence on the performance. Therefore, it is necessary to provide a simple, feasible, scientific and reasonable material combination design method and an evaluation method for crack resistance thereof.

For the material combination design of the fiber asphalt macadam, the types and the characteristics of materials such as asphalt binder, macadam and fiber are determined according to engineering requirements, an empirical method is adopted as a main factor according to factors such as engineering purposes, road traffic, pavement structure design and construction seasons, the dosage ranges of various materials are comprehensively determined by combining theories, and necessary and reasonable adjustment is carried out according to test results. In this section, a flexible seal combination design method based on a fiber-asphalt combined material tensile test is provided, and the combination design and the optimal use amount of the material are determined by taking the anti-cracking performance of the flexible seal material as a main control index.

Two different asphalt binders were considered during the test: modified emulsified asphalt and SBS modified asphalt; the macadam mainly plays a role in protecting the seal material and bearing construction load, and has little influence on the anti-cracking effect of the seal, so the macadam is not considered in the test. Firstly, according to the existing specifications and engineering experience, the dosage range of the materials is determined: the fiber measuring amount is 60-100 g/m ² The amount of the modified emulsified asphalt is 1.6-2.2 kg/m ² The amount of the SBS modified asphalt is 1.1-1.8 kg/m ² And the length of the fiber is 4-6 cm. An orthogonal design analysis table of 3-factor 3 levels was established based on the material usage range, as shown in table 12.

TABLE 12 orthogonal test design for material combinations

The combined material tensile test adopts an aluminum alloy mold with the size of l00mm multiplied by 70 multiplied by 30mm to manufacture a test piece, a layer of silicone oil paper is pasted in the mold before the test piece is molded, and the demolding after the test piece is molded is facilitated; then, sequentially spraying a layer of asphalt, a layer of fiber and a layer of asphalt into the die according to the mixing ratio; and standing the test piece for a period of time after the test piece is manufactured, and demolding after the asphalt is cooled.

During testing, the test piece is clamped and fixed by a clamp, the distance between the clamps is adjusted, then loading is carried out through a UTM testing machine, the loading rate is 20mm/min, the testing temperature is 25 ℃, a testing system automatically collects stress and strain data, and loading is stopped when the tensile stress of the test piece is attenuated to 90% of the maximum value.

Table 13Thermal physical parameters of each structural layer of the pavement

Numbering	Factor 1: modified emulsified asphalt dosage	Fiber amount (g/m) ² )	Fiber length (cm)
				K1	1.131	1.063	1.094
K2	1.380	1.284	1.308
				K3	1.122	1.286	1.231
k1	0.377	0.354	0.365
				k2	0.460	0.428	0.436
k3	0.374	0.429	0.410
				Extreme difference R	0.086	0.075	0.071

TABLE 14 orthogonal analysis results of tensile strength of SBS modified asphalt group

Numbering	The dosage (kg/m) of SBS modified asphalt ² )	Fiber dosage (g/m) ² )	Fiber length (cm)
				K1	1.358	1.191	1.201
K2	1.362	1.341	1.332
				K3	1.11	1.298	1.297
k1	0.453	0.397	0.400
				k2	0.454	0.447	0.444
k3	0.370	0.433	0.432
				Extreme difference R	0.084	0.050	0.044

According to the analysis result of the orthogonal test, the following results are obtained: whether modified emulsified asphalt or SBS modified asphalt is adopted, the most main factor influencing the tensile strength of the fiber-asphalt composite material can be judged through the range of the difference, namely the asphalt dosage, the fiber dosage and the fiber length. Therefore, the influence factor of the fiber length is weakened, and according to the feedback condition of a field test, when the length is selected to be 4cm, the spreading effect of the fiber is the best, the fiber is easier to disperse, the agglomeration phenomenon is less, the asphalt covers the fiber more fully, so that the subsequent fiber length is selected to be 4 cm.

Respectively analyzing the dosage of the modified emulsified asphalt and the SBS modified asphalt, wherein the dosage of the modified emulsified asphalt is 1.9kg/m ² The amount of the fibers used was 75g/m as the median ² The amount of SBS modified asphalt is 1.5kg/m ² The fiber amount is 75g/m as the median ² Is the median value.

And selecting proper difference value to carry out mix proportion design. And selecting proper difference values to carry out mix proportion design.

The dosage of the modified emulsified asphalt is 1.8kg/m ² -2.0kg/m ² In the dosage range, the fiber and the modified emulsified asphalt have good interface contact effect, and the formed asphalt fiber network structure is compact. As can be seen from the above test results, when the fiber length was taken to be 4cm, the amount of the modified emulsified asphalt was 2.0kg/m ² The fiber dosage is respectively 75g/m ² When the tensile strength of the fiber-asphalt composite material test piece is not increased, the fiber-asphalt composite material test piece is not increased.

The dosage of SBS modified asphalt is 1.4kg/m ² -1.6kg/m ² In the dosage range, the fiber and the SBS modified asphalt have good interface contact effect, and the formed asphalt fiber mesh structure is compact. As can be seen from the above test results, the amount of SBS modified asphalt used was 1.6kg/m when the fiber length was 4cm ² The dosage of the fiber is 75g/m ² When the fiber-asphalt composite material is used, the test piece of the fiber-asphalt composite material has higher tensile strength.

Microscopic shooting is carried out on the fiber asphalt contact interface through an electron microscope, and the contact microscopic view of the asphalt fiber interface is analyzed, so that the following results can be obtained:

the fiber asphalt strip structure has 'free fiber' and 'structural fiber'. The fibers can 'reinforce' the adsorbed asphalt by virtue of the excellent asphalt adsorption capacity, and the fibers which are distributed in a staggered manner are connected through the adsorbed asphalt, wherein the stable lap joint structure of the structural fibers can well exert and strengthen the tensile resistance of the fibers, and bear and absorb most of tensile stress applied to the plate strip structure. Free fibers free from the lap joint structure exist in the structure, and the free fibers cannot be in lap joint with other fibers through adsorbed asphalt, so that the tensile resistance of the free fibers is not exerted, and the integrity of the plate strip structure is reduced.

The asphalt-fiber contact interface is amplified through an electron microscope, so that the rough outer surface of the fiber can well adsorb asphalt, the adsorbed asphalt is stably connected with the fiber to form structural asphalt with stable performance, and the stress diffusion capacity among the fibers can be improved through the structural asphalt. And asphalt which cannot be adsorbed by the fibers in the structure becomes free asphalt, and the tensile resistance of the free asphalt is poor, so that when the slab band test piece is stressed, the structure where the free asphalt is located can be quickly damaged, and the overall tensile resistance of the test piece is reduced.

When the fracture performance of the asphalt mixture is researched, a trabecular bending test and an indirect tensile test are commonly adopted. However, researchers find that in the actual stress situation, the stress situation of the asphalt pavement is different from that of the trabecular bending test, and the test result obtained by the trabecular test piece has certain limitation on the evaluation of the pavement fracture performance.

In recent years, a completely new test method is used in the study of the asphalt mixing shaking performance, and the method is called Semi-Circular bonding test (SCB test for short) abroad. The researchers find out that the following results are obtained by comparing the test results: the semi-circle bending test result is closer to the actual stress result of the asphalt mixture. The semicircular test piece is relatively simple to manufacture and wide in source, can be obtained by drilling a core on site and sampling, and can also be formed by cutting a Marshall test piece through rotary compaction.

Therefore, in order to better simulate the anti-cracking performance of the fiber asphalt flexible sealing layer technology (hereinafter referred to as 'flexible sealing layer') under the actual stress condition, the fiber asphalt flexible sealing layer technology is added into a semicircular test piece through secondary cutting and spreading, an SCB test is carried out on the formed combined test piece, and the good and bad anti-cracking performance of the flexible sealing layer technology is simulated under the actual road surface stress condition through establishing a blank control group.

And (3) selecting the mix proportion of the asphalt mixture, namely, directly selecting a standard recommended grading median value for the grading distribution adopted by the SCB test piece for the test to carry out mix proportion design. The specification grading range of AC-13 is shown in Table 15.

TABLE 15 AC-13 grading Range

Sieve mesh size (mm)	16	13.2	9.5	4.75	2.36	1.18	0.6	0.3	0.15	0.075
											Grading Upper Limit (%)	100	100	79	53	40	32	24	18	11	7
Grading lower limit (%)	100	95	68	38	32	23	17	9	6	3
											Composition grading (%)	100	96.4	74.2	51.9	33.7	25.4	22.7	15.3	7.8	4.8

The method for determining the optimal asphalt-stone ratio in the reference specification selects five groups of asphalt mixtures with the asphalt dosages of 4.5%, 5.0%, 5.5%, 6.0% and 6.5% according to actual engineering experience for design. Firstly, five groups of standard Marshall test pieces with different asphalt dosages are manufactured, the size of the Marshall test piece is measured after the test piece is molded, and the next test can be carried out only after the size meets the requirement. The optimum asphalt dosage of AC-13 is finally determined to be 5.1% according to the test results. According to the test results, under the condition that the optimal asphalt content is 5.1%, the test results of the AC-13 mixture meet the standard requirements, so that the AC-13 mixture can be used for subsequent tests.

TABLE 16 results of tests relating to AC-13 blends with an optimum bitumen content of 5.1%

Detecting items	Quality index	Practical results
			Stability MS (kN)	≥8.0	18.2
Flow value FL (mm)	1.5-4	2.76
			Void ratio VV (%)	3-5	4.05
Asphalt saturation (VFA)	65-75	72.63
			Mineral aggregate void fraction (VMA)	≥13	15.44
Maximum theoretical density (kg/m) ³ )	Is free of	2.548
			Bulk density (kg/m) ³ )	Is free of	2.457

Mix proportion selection of asphalt fiber seal coat

The asphalt fiber interlayer adopted by the sealing layer of the composite test piece adopts the mixing ratio shown in the table 17 and the table 18 to manufacture the test pieces, and three groups of each test piece are manufactured.

TABLE 17 compounding ratio of modified emulsified asphalt fiber seal in SCB test pieces

TABLE 18 compounding ratio of SBS modified asphalt fiber seal in SCB test piece

Wherein the fiber dosage is 0g/m ² The seal test group was a control group, and hereinafter referred to as "normal seal", and the rest as "flexible seal".

Test piece manufacturing process

In the present study, a semi-circular test piece of the mixture having a thickness of 70mm was used as a basic SCB test piece in consideration of the uniformity of the fiber spreading. The forming test piece is based on the SCB test piece, and a flexible sealing layer is added into the interlayer through secondary cutting of the SCB test piece, so that the composite test piece with the flexible sealing layer is formed. And finally, carrying out bottom crack cutting on the composite test piece to simulate a reflection crack. The size of the cut is 2mm in width and 15mm in height.

Energy-based evaluation index analysis for crack resistance performance of semicircular bending test

Research shows that the fracture energy can well represent the crack resistance of the asphalt. The fracture energy was calculated from the load force-displacement curve.

The fracture energy is equal to the area under the load-displacement curve, reflecting the total energy absorbed by the material from intact to fractured. When the work of the external load is great enough, the composite test piece will crack. The fracture energy is an energy index, the strength of the fracture resistance of the test piece can be reflected by the fracture energy, and the larger the fracture energy is, the better the crack resistance of the test piece is.

Test results

When the seal structure binding material adopts modified emulsified asphalt, the test results are processed as follows:

TABLE 19 fracture energy of modified emulsified asphalt SCB test pieces

When the sealing structure adhesive material adopts SBS modified asphalt, the test results are processed as follows:

TABLE 20 SBS modified asphalt SCB test pieces fracture energy

When the adhesive material adopts modified emulsified asphalt, the fiber dosage is from 0g/m at the test temperature of 5 DEG C ² Increased to 75g/m ² The fracture energy of the composite structure is increased from 3.144J to 5.249J, and the fracture energy is increased by 66.95%; the fiber consumption is 0g/m at the test temperature of 25 DEG C ² Increased to 75g/m ² The composite structure has breaking energy increased from 1.969J to 3.527J and breaking energy increased by 79.13%.

When the adhesive material adopts modified emulsified asphalt, the fiber dosage is from 0g/m at the test temperature of 5 DEG C ² Increased to 75g/m ² The breaking energy is increased from 3.211J to 5.386J, and the breaking energy is increased by 67.74%; test ofAt 25 deg.C, the fiber amount is 0g/m ² Increased to 75g/m ² The breaking energy increased from 2.056J to 3.612J, which is 75.68%.

The test results are analyzed, and the test group adopting the flexible sealing layer has the advantages that the test group adopting the common sealing layer has obviously better results, and through analysis, fibers in the structure are the main reasons for the size difference of the fracture energy. The fiber has strong bending and pulling resistance effects, and compared with a common seal layer, the fiber in the flexible seal layer can adsorb free asphalt in the seal layer, and the adsorbed free asphalt is converted into firm and stable structural asphalt and structural fiber which are stably connected with an upper asphalt mixture structure and a lower asphalt mixture structure, so that the overall cracking resistance and bending and pulling resistance of the flexible seal layer structure are enhanced. When the flexible sealing layer is under the action of concentrated stress generated by lower reflection cracks, firstly, part of stress can be absorbed and diffused through the strong anti-stretching deformation capacity of the flexible sealing layer (the structural fiber absorbs and diffuses the bending tensile stress), secondly, in the later stress process, part of stress can be absorbed by the structural asphalt (the structural asphalt is damaged), the two parts absorb the concentrated stress transmitted by a large number of lower reflection cracks, a large amount of energy can be consumed in the process, the damage speed of the test piece is slowed down, and the integral fracture energy of the test piece is increased.

In summary, when the binder is modified emulsified asphalt, the optimal mixing ratio of the fiber asphalt is as follows: the dosage of the modified emulsified asphalt is 2.0kg/m ² The dosage of the glass fiber is 75g/m ² At the moment, the crack resistance of the combined structure is the best; when the adhesive material adopts SBS modified asphalt, the optimal dosage of the main materials of the seal layer is as follows: the dosage of SBS modified asphalt is 1.6kg/m ² The fiber dosage is 75g/m ² At this time, the crack resistance of the composite structure is the best.

The invention provides a solution adopting a fiber asphalt macadam flexible seal technology based on the problems of interlayer diseases and reflection cracks of the existing asphalt pavement, and the fiber asphalt macadam flexible seal technology is explored from the selection of materials, the design of mix proportion, the design of indoor tests and field tests. The design of the mix proportion of the fiber asphalt macadam flexible seal is determined through a plate strip tensile test and a semicircular bending test, and the anti-cracking effect of the technology is verified. The main conclusions are as follows:

the effect of the fiber-asphalt composite structure involves three factors: pitch usage, fiber usage, and fiber length. The three factors are subjected to orthogonal test design, and result analysis and factor analysis of the test show that whether the asphalt adopts modified emulsified asphalt or SBS modified asphalt, the main factor influencing the effect of the combined structure is the asphalt dosage, and then the fiber dosage and the fiber length.

The semi-circle bending test is combined with the fiber asphalt lower seal technology for the first time, and the crack resistance of the lower seal technology is verified through a combined test piece. And (3) introducing an evaluation index of fracture energy to test results from the energy angle, and discussing whether the fiber asphalt lower seal layer technology has an obvious effect on the improvement effect of the structural crack resistance. The test results are analyzed and processed, and the results show that no matter the temperature is 5 ℃ or 25 ℃, under the condition that the asphalt consumption and the fiber length are constant values, the integral fracture energy of the test piece with the fibers is larger than that of the test piece without the fibers, mainly because of the existence of the fibers, when a reticular structure formed by the fiber asphalt is subjected to the action of structural reflection cracks, a large amount of fibers can generate the phenomena of interface debonding and fiber pulling-out, and the processes all need to consume energy, so that the integral fracture energy of the test piece is increased.

The above description is only an alternative embodiment of the present invention, and not intended to limit the scope of the present invention, and all modifications and equivalents of the present invention, which are made by the contents of the present specification and the accompanying drawings, or directly/indirectly applied to other related technical fields, are included in the scope of the present invention.

Claims

1. The utility model provides a highway seal coat which characterized in that includes first pitch layer, fibrous layer, second pitch layer and the metalling that forms from bottom to top in proper order.

2. The pavement sealing according to claim 1, wherein the first asphalt layer and the second asphalt layer are each made of any one of SBS modified asphalt, emulsified asphalt, and rubber asphalt.

3. The road sealing layer according to claim 2, wherein when said first asphalt layer is made from said SBS modified asphalt, the amount of said SBS modified asphalt used per square meter is from 1.1 kg to 1.8 kg;

4. The road sealing layer according to claim 2, wherein when said second asphalt layer is made from said SBS modified asphalt, the amount of said SBS modified asphalt used per square meter is from 1.1 kg to 1.8 kg;

5. The road cover according to claim 2, wherein the amount of SBS modified asphalt used is from 1.1 kg to 2.1 kg per square meter; alternatively, the first and second electrodes may be,

6. The road seal of claim 1, wherein the fibrous layer is made of fiberglass or basalt fibers.

7. The pavement sealing layer of claim 6, wherein the glass fibers or basalt fibers have a length of 30mm to 120 mm.

8. The highway sealing layer according to any one of claims 1 to 7, wherein when the highway sealing layer is applied to a water-stable sealing layer, the crushed stone used for forming the crushed stone layer has a particle size of 4.75mm to 13.2 mm;

alternatively, the first and second electrodes may be,

when the road sealing layer is applied to a bridge deck, the particle size of the crushed stone used for forming the crushed stone layer is less than or equal to 9.5 mm.

9. The pavement sealing layer of claim 8 wherein the crushed stone layer has a thickness of 0.8cm to 1.3 cm.

10. A pavement structure comprising a pavement covering according to any of claims 1 to 9.