CN111517733A - Emulsified asphalt pavement regeneration material capable of reducing cracking and preparation and construction methods thereof - Google Patents

Abstract

The invention provides an emulsified asphalt pavement recycled material capable of reducing cracking and a preparation and construction method thereof, relating to the technical field of highways and municipal engineering, and being capable of improving the strength of the recycled material and reducing the shrinkage cracking rate thereof, thereby improving the overall bearing capacity of the pavement and prolonging the service life of the pavement; the regenerated material comprises the following components in parts by mass: 70-85 parts of asphalt pavement recycling material, 15-29 parts of broken stone, 1.0-1.5 parts of old asphalt activator, 3.5-5.0 parts of emulsified asphalt, 1-2 parts of slag sulphoaluminate and/or iron aluminate cement and 0.1-1.0 part of fiber; the emulsified asphalt comprises the following components in parts by mass: 62-70 parts of matrix asphalt, 2-4 parts of emulsifier and 30-38 parts of water; the cement comprises the following components in parts by mass: 75-90 parts of granulated blast furnace slag, 3-5 parts of sulphur or iron aluminate cement clinker and 3-15 parts of gypsum. The technical scheme provided by the invention is suitable for the processes of material preparation and road paving.

Description

Emulsified asphalt pavement regeneration material capable of reducing cracking and preparation and construction methods thereof

[ technical field ] A method for producing a semiconductor device

The invention relates to the technical field of highways and municipal engineering, in particular to an emulsified asphalt pavement regeneration material for reducing cracking and a preparation and construction method thereof.

[ background of the invention ]

The highway construction in China develops rapidly, and calculated according to the design life of asphalt for 15-20 years, about 12% of asphalt pavements need to be overhauled every year from now on, and the speed of the asphalt pavements is increased by 15% every year. If the waste materials are completely recycled, the material cost can be saved by 120 billion yuan each year, and the generated environmental benefit is more huge. The cold regeneration technology can effectively solve the problem of resource waste, and can save the total investment by 40 to 50 percent compared with other traditional construction methods. However, the technology is mostly used for the base course of low-grade roads at present, the utilization rate of waste materials is low, and the economic benefit brought by the technology is undoubtedly huge if the cold regeneration technology can be smoothly introduced into the reconstruction of the first-grade and second-grade roads in China.

The cold regeneration construction process of the emulsified asphalt is efficient, the utilization rate of the pavement regenerated aggregate is high, the cold regeneration technology of the emulsified asphalt is constructed at normal temperature, the asphalt does not need to be heated, and the performance attenuation caused by the high-temperature aging of the asphalt is avoided, so that the fatigue resistance of the pavement is improved, and the service life of the pavement is prolonged. Meanwhile, the technology can accurately control the thickness of the paving layer, improve the service performance of the pavement and improve the grade of the old road without damaging the roadbed. In the treatment of asphalt pavement ruts, load cracks, non-load cracks and other diseases and pavement overhaul projects, the emulsified asphalt cold regeneration technology can greatly improve the overall quality of a highway, reduce the construction cost in the service life cycle of the highway, save a large amount of land and mineral resources, be favorable for protecting the ecological environment, and has the advantages of simple construction, fast progress, early open traffic and less influence on the traffic, and is particularly suitable for the reconstruction and the upgrade of old roads with heavy traffic.

However, in the prior art, the problems of poor early bonding property of strength formation, loose aggregate, threshing, insufficient stability and the like still exist among cold recycled mixtures, which are mainly related to the demulsification speed of emulsified asphalt, the grading of recycled materials and the cement performance.

Accordingly, there is a need to develop a crack reducing emulsified asphalt pavement recycling material and a method of making and constructing the same to address the deficiencies of the prior art and to solve or mitigate one or more of the problems set forth above.

[ summary of the invention ]

In view of the above, the invention provides a cracking-reduced emulsified asphalt pavement recycled material and a preparation and construction method thereof, which have higher strength and lower shrinkage cracking rate, thereby improving the overall bearing capacity of the emulsified asphalt recycled material as a base layer or a lower surface layer and prolonging the service life of a pavement.

On one hand, the invention provides an emulsified asphalt pavement recycled material capable of reducing cracking, which is characterized by comprising the following components in parts by mass: 70-85 parts of asphalt pavement recycling material, 15-29 parts of broken stone, 1.0-1.5 parts of old asphalt activator, 3.5-5.0 parts of emulsified asphalt, 1-2 parts of slag sulphoaluminate and/or iron aluminate cement and 0.1-1.0 part of fiber.

The above aspects and any possible implementation manners further provide an implementation manner, wherein the slag sulfoaluminate or ferroaluminate cement comprises the following components in parts by mass: 75-90 parts of granulated blast furnace slag, 3-5 parts of sulphur or iron aluminate cement clinker and 3-15 parts of gypsum.

The above aspects and any possible implementations further provide an implementation where the 28d compressive strength of the sulfur or iron aluminate cement clinker is greater than or equal to 50 MPa.

The above aspects and any possible implementations further provide an implementation where the initial setting time of the slag sulfoaluminate or ferro-aluminate cement is 6 hours or more, the final setting time is 10 hours or less, the 7-day linear expansion rate is 0.15% or more, and the 28-day free expansion rate is 1.0% or less.

The above aspects and any possible implementation further provide an implementation, in which the emulsified asphalt is emulsified with a base asphalt; the emulsified asphalt comprises, by mass, 62-70 parts of base asphalt, 2-4 parts of an emulsifier and 30-38 parts of water.

The above aspects and any possible implementations further provide an implementation, and the base asphalt is 70# or 90# common road petroleum asphalt.

The above aspects and any possible implementation manners further provide an implementation manner, and the recycled asphalt pavement material is crushed stone material recycled after milling and crushing the old asphalt pavement.

The above aspects and any possible implementations further provide an implementation in which the fibers are one or more of organic fibers, polymer fibers, basalt fibers, and recycled fibers.

In another aspect, the present invention provides a method for preparing a recycled emulsified asphalt pavement material with reduced cracking, which is characterized in that the method is suitable for preparing the recycled material as described in any one of the above; the method comprises the following steps:

s1, adding the emulsifier into water according to the mass parts, uniformly stirring to prepare soap liquid, heating to 55-65 ℃, and preserving heat;

s2, pouring the soap solution prepared in the S1 into a colloid mill or equipment with the same function as the colloid mill for circulation, slowly adding matrix asphalt with the temperature of 125-135 ℃ while performing circulation shearing, and continuing to perform circulation shearing for 0.5-2 minutes after all the matrix asphalt is added to prepare emulsified asphalt;

and S3, mixing the asphalt pavement recycling material, broken stone, old asphalt activator, slag sulphoaluminate and/or ferro-aluminate cement, fiber and the emulsified asphalt prepared in the S2 according to the mass parts, and uniformly stirring at room temperature to obtain the emulsified asphalt pavement recycling material.

In another aspect, the invention provides a construction method of an emulsified asphalt pavement recycled material for reducing cracking, which is characterized in that the recycled material is adopted to pave a pavement; the construction method comprises the steps of paving, rolling and curing;

paving: paving the base material by adopting paving equipment with paving power not lower than 120kW, wherein the paving thickness is 8-15cm after single-layer rolling; the two adjacent construction sections are longitudinally overlapped by 30-40 cm;

rolling: the method comprises the steps of initial pressing, secondary pressing and final pressing; firstly, carrying out 2-3 back-and-forth static pressures on the road surface by using rolling equipment with the effect equal to that of a double-steel-wheel road roller, namely primary pressure; then heavy vibration rolling equipment with the exciting force larger than 35t, 18-21t three-wheel rolling equipment or tire rolling equipment with the exciting force more than 25t are used for continuously rolling and compacting, namely re-rolling; finally, static pressure of rolling equipment or rubber wheel rolling equipment with the same effect as that of the double-steel-wheel road roller is adopted to eliminate wheel tracks, namely final pressure is obtained;

health preserving: after finishing rolling on each section of pavement and checking the compactness to be qualified, immediately starting to maintain; natural health preserving is adopted; the life span is not less than 3 days.

Compared with the prior art, the invention can obtain the following technical effects: the recycled material has higher strength and lower shrinkage cracking rate, thereby improving the integral bearing capacity and the service life of the pavement when the emulsified asphalt recycled material is used as a base layer or a lower surface layer, and being used for building a long-life asphalt pavement of a semi-rigid base layer.

Of course, it is not necessary for any one product in which the invention is practiced to achieve all of the above-described technical effects simultaneously.

[ description of the drawings ]

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings needed to be used in the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without creative efforts.

FIG. 1 is a composition diagram of a low-crack emulsified asphalt pavement recycling material provided by an embodiment of the invention.

[ detailed description ] embodiments

For better understanding of the technical solutions of the present invention, the following detailed descriptions of the embodiments of the present invention are provided with reference to the accompanying drawings.

It should be understood that the described embodiments are only some embodiments of the invention, and not all 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.

The terminology used in the embodiments of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used in the examples of the present invention and the appended claims, the singular forms "a," "an," and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise.

Aiming at the defects of the prior art, the invention provides a recycled material of an emulsified asphalt pavement, which reduces cracking, improves the tensile property and toughness of the material by preparing the recycled material of the emulsified asphalt by using slag or steel slag sulphoaluminate cement and fibers, and makes the ductility of the material enhanced very important. The concrete scheme is that novel slag sulphoaluminate cement and fiber are added into the traditional emulsified asphalt regeneration mixture, so that the asphalt regeneration material is obtained and is applied to the upper base layer and even the lower surface layer of the pavement. By utilizing the characteristics of the slag sulphoaluminate (ferro) cement and adding fibers, the strength of the recycled mixture is improved, and meanwhile, the cracking of a base layer is reduced.

As shown in figure 1, the cracking-reducing emulsified asphalt regeneration material comprises the following main components in parts by weight: 70-85 parts of asphalt pavement recycling material, 15-29 parts of broken stone, 1-1.5 parts of old asphalt activator, 3.5-5 parts of emulsified asphalt, 1-2 parts of slag sulpho (ferro) aluminate cement and/or steel slag cement and 0.5-1 part of fiber.

The slag sulphoaluminate (ferro) cement comprises the following main components in parts by mass: 75-90 parts of granulated blast furnace slag, 3-5 parts of sulphoaluminate cement clinker and 3-15 parts of gypsum. The above-mentioned sulphoaluminate cement has a mark number of above 42.5, and the cement clinker strength is greater than or equal to 50MPa (28d compressive strength). The initial setting time of the slag sulphoaluminate (ferro) cement is more than or equal to 6 hours, the final setting time is less than or equal to 10 hours, the 7-day linear expansion rate is more than or equal to 0.15 percent, and the 28-day free expansion rate is less than or equal to 1.0 percent.

The steel slag cement can be steel slag sulphoaluminate cement, replaces slag sulphoaluminate cement and slag ferroaluminate cement to be used in the emulsified asphalt regeneration material, and the components of the steel slag cement are the same as those of the slag cement. The steel slag sulphoaluminate cement comprises the following components: 75-90 parts of granulated blast furnace steel slag, 3-5 parts of sulphoaluminate cement clinker and 3-15 parts of gypsum.

The emulsified asphalt is prepared by emulsifying matrix asphalt, wherein the matrix asphalt is 70# or 90# common road petroleum asphalt, and the emulsified asphalt comprises the following main components in parts by weight: 62-70 parts of matrix asphalt, 2-4 parts of emulsifier and 30-38 parts of water.

The asphalt pavement recycling material (RAP) refers to a crushed stone material recycled after milling and crushing an original old asphalt pavement. The recycling can be realized by a local recycling machine, or the milled powder can be transported back to a mixing plant for recycling.

The fibers used may be one or more of organic fibers, polymer fibers, basalt fibers, recycled fibers, and the like. The fibers mainly play a role in reinforcing, are uniformly distributed in the regenerated mixture, can bear the shearing action formed in the running process of the vehicle, and improve the shearing resistance of the mixture. The regenerated fiber is obtained by recycling, cleaning and crushing waste fibers; the regenerated fiber is one or more of regenerated woven bag fiber, regenerated glass fiber and regenerated polyester fiber.

1. When the emulsified asphalt pavement regeneration material is prepared, special mixing equipment can be adopted for on-site cold regeneration mixing. The concrete mixing flow is as follows:

(1) weighing the raw material components according to the requirements of the components of the mixture;

(2) adding emulsifier into water, stirring uniformly to prepare soap liquid, heating to 55-65 ℃, and preserving heat;

(3) pouring the soap solution prepared in the step (2) into a colloid mill for circulation, slowly adding hot matrix asphalt while performing circular shearing, wherein the temperature of the matrix asphalt is 125-135 ℃, and continuously performing circular shearing for 0.5-2 minutes (preferably 1 minute) after all the matrix asphalt is added into the colloid mill to prepare emulsified asphalt;

(4) and (3) mixing RAP, broken stone, old asphalt activator, cement, fiber and the emulsified asphalt prepared in the step (3), and uniformly stirring at room temperature to obtain the emulsified asphalt cold-recycling mixture.

2. The prepared emulsified asphalt cold-recycling mixture is paved by taking the following matters into consideration:

A) the asphalt paver is recommended to be used for paving, the paving thickness of the mixture is guaranteed to be enough, the paving thickness of each layer is not smaller than 8cm (the thickness after rolling forming), and the maximum thickness is not larger than 15 cm.

B) And after the construction quality of the lower bearing layer is detected to be qualified, the upper structural layer can be paved. When two-layer continuous paving is adopted, when the quality of the lower layer is in problem, the upper layer is processed at the same time.

C) And paving the mixture by adopting an asphalt concrete paver or a stable material paver with the paving power not lower than 120 kW.

D) And when two spreading machines are adopted for parallel spreading, the models and the delivery periods of the two spreading machines are the same. During construction, the distance between the front part and the rear part of the two pavers is not more than 10m, and the longitudinal overlapping of the two construction sections by 30-40cm is ensured.

E) Specially-assigned persons are arranged behind the spreading machine to eliminate the segregation phenomenon of coarse and fine aggregates, and particularly, local coarse aggregate pits are removed and filled with a newly-mixed mixture.

F) In order to reduce waste and facilitate edge rolling, the formwork is suitable to be erected longitudinally.

3. When rolling the paved cold recycled emulsified asphalt mixture, the following matters need to be paid attention to:

A) and in order to ensure the rolling quality of the material, the rolling process is finished before the initial setting of the cement.

B) And in order to ensure the rolling effect, a construction unit is provided with enough rolling equipment. For a bidirectional four-lane highway or a first-level highway, at least 4 heavy road rollers are needed for half-width paving; for the half-width paving of the bidirectional six lanes, at least 5 heavy-duty road rollers are needed.

C) Generally divided into initial pressure, secondary pressure and final pressure; firstly, carrying out 2-3 back-and-forth static pressures on the road surface by using rolling equipment with the effect equal to that of a double-steel-wheel road roller, namely primary pressure; then heavy vibration rolling equipment with the exciting force larger than 35t, 18-21t three-wheel rolling equipment or tire rolling equipment with the exciting force more than 25t are used for continuously rolling and compacting, namely re-rolling; and finally, static pressure of rolling equipment or rubber wheel rolling equipment with the same effect as that of the double-steel-wheel road roller is adopted to eliminate wheel tracks, namely final pressure is obtained.

D) And if a spring phenomenon is found in the rolling process, digging out the mixed material on the road section, and replacing new filling materials for rolling again.

E) The surface after rolling and forming should be flat and have no wheel tracks.

4. When maintaining the rolled pavement, the following matters need to be paid attention:

A) and after finishing rolling of each section and passing the compaction degree inspection, immediately starting curing. Natural health preserving is adopted.

B) The life-preserving period is not less than 3 days. For the roads at the second level and below the second level, if the curing period is less than 3d, namely an asphalt surface course is paved, the heavy vehicles are limited to pass.

Specific road performance indices are shown in table 1.

TABLE 1 road Performance index

Actual measurement item	Technical requirements
		Marshall stability (KN) at 40 DEG C	≥14
Dry split strength at 15 ℃ (MPa)	≥0.65
		Residual stability (%)	≥75
Freeze-thaw split strength ratio (%)	≥70
		Degree of dynamic stability (times/mm)	≥3000

The invention mainly utilizes the advantages of high breaking strength, low hydrothermal degree, small shrinkage and the like of slag sulphoaluminate to prepare the emulsified asphalt regeneration material, and simultaneously adds the fiber material to further increase the breaking strength and realize the purpose of reducing cracking.

Has more advantages than other existing products.

The emulsified asphalt pavement recycled material for reducing cracking and the preparation and construction method thereof provided by the embodiment of the application are described in detail above. The above description of the embodiments is only for the purpose of helping to understand the method of the present application and its core ideas; meanwhile, for a person skilled in the art, according to the idea of the present application, there may be variations in the specific embodiments and the application scope, and in summary, the content of the present specification should not be construed as a limitation to the present application.

As used in the specification and claims, certain terms are used to refer to particular components. As one skilled in the art will appreciate, manufacturers may refer to a component by different names. This specification and claims do not intend to distinguish between components that differ in name but not function. In the following description and in the claims, the terms "include" and "comprise" are used in an open-ended fashion, and thus should be interpreted to mean "include, but not limited to. "substantially" means within an acceptable error range, and a person skilled in the art can solve the technical problem within a certain error range to substantially achieve the technical effect. The description which follows is a preferred embodiment of the present application, but is made for the purpose of illustrating the general principles of the application and not for the purpose of limiting the scope of the application. The protection scope of the present application shall be subject to the definitions of the appended claims.

It is also noted that the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a good or system that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such good or system. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other like elements in a commodity or system that includes the element.

It should be understood that the term "and/or" as used herein is merely one type of association that describes an associated object, meaning that three relationships may exist, e.g., a and/or B may mean: a exists alone, A and B exist simultaneously, and B exists alone. In addition, the character "/" herein generally indicates that the former and latter related objects are in an "or" relationship.

The foregoing description shows and describes several preferred embodiments of the present application, but as aforementioned, it is to be understood that the application is not limited to the forms disclosed herein, but is not to be construed as excluding other embodiments and is capable of use in various other combinations, modifications, and environments and is capable of changes within the scope of the application as described herein, commensurate with the above teachings, or the skill or knowledge of the relevant art. And that modifications and variations may be effected by those skilled in the art without departing from the spirit and scope of the application, which is to be protected by the claims appended hereto.

Claims (10)

1. The emulsified asphalt pavement regeneration material capable of reducing cracking is characterized by comprising the following components in parts by mass: 70-85 parts of asphalt pavement recycling material, 15-29 parts of broken stone, 1.0-1.5 parts of old asphalt activator, 3.5-5.0 parts of emulsified asphalt, 1-2 parts of slag cement and/or steel slag cement and 0.1-1.0 part of fiber.

2. The emulsified asphalt pavement recycling material with reduced cracking as set forth in claim 1, wherein said slag cement is a slag sulfoaluminate and/or ferroaluminate cement; the slag sulphoaluminate or ferroaluminate cement comprises the following components in parts by mass: 75-90 parts of granulated blast furnace slag, 3-5 parts of sulphur or iron aluminate cement clinker and 3-15 parts of gypsum.

3. The emulsified asphalt pavement recycling material with reduced cracking as set forth in claim 2, wherein said sulfur or iron aluminate cement clinker has a 28d compressive strength of 50MPa or more.

4. The emulsified asphalt pavement regenerative material with reduced cracking as claimed in claim 2 or 3, wherein the initial setting time of the sulfoaluminate slag or the ferro-aluminate cement is not less than 6 hours, the final setting time is not more than 10 hours, the 7-day linear expansion rate is not less than 0.15%, and the 28-day free expansion rate is not more than 1.0%.

5. The emulsified asphalt pavement recycling material for reducing cracking as claimed in claim 1, wherein the emulsified asphalt is emulsified with base asphalt; the emulsified asphalt comprises, by mass, 62-70 parts of base asphalt, 2-4 parts of an emulsifier and 30-38 parts of water.

6. The emulsified asphalt pavement recycling material for reducing cracking as claimed in claim 5, wherein the base asphalt is 70# or 90# ordinary road petroleum asphalt.

7. The emulsified asphalt pavement recycling material with reduced cracking as claimed in claim 1, wherein the asphalt pavement recycling material is crushed stone material recovered from old asphalt pavement after milling and crushing.

8. The emulsified asphalt pavement recycling material for reducing cracking of claim 1, wherein the fibers are one or more of organic fibers, polymer fibers, basalt fibers and recycled fibers.

9. A method for preparing a crack-reducing emulsified asphalt pavement recycled material, which is characterized in that the method is suitable for preparing the recycled material of any one of claims 1 to 8; the method comprises the following steps:

s1, adding the emulsifier into water according to the mass parts, uniformly stirring to prepare soap liquid, heating to 55-65 ℃, and preserving heat;

s2, pouring the soap solution prepared in the S1 into a colloid mill or equipment with the same function as the colloid mill for circulation, slowly adding matrix asphalt with the temperature of 125-135 ℃ while performing circulation shearing, and continuing to perform circulation shearing for 0.5-2 minutes after all the matrix asphalt is added to prepare emulsified asphalt;

and S3, mixing the asphalt pavement recycling material, broken stone, old asphalt activator, slag sulphoaluminate and/or ferro-aluminate cement, fiber and the emulsified asphalt prepared in the S2 according to the mass parts, and uniformly stirring at room temperature to obtain the emulsified asphalt pavement recycling material.

10. A construction method of an emulsified asphalt pavement recycled material for reducing cracking, which is characterized in that pavement is carried out by adopting the recycled material as claimed in any one of claims 1 to 8; the construction method comprises the steps of paving, rolling and curing;

paving: paving the base material by adopting paving equipment with paving power not lower than 120kW, wherein the paving thickness is 8-15cm after single-layer rolling; the two adjacent construction sections are longitudinally overlapped by 30-40 cm;

rolling: dividing into initial pressure, secondary pressure and final pressure; the initial pressing is static pressing for 2-3 times by adopting a rolling device; the re-pressing is to use vibration rolling equipment or heavy rolling equipment to roll and compact; the final pressing is to adopt a double-steel wheel rolling device or a rubber wheel rolling device to carry out static pressure so as to eliminate wheel tracks;

health preserving: after finishing rolling on each section of pavement and checking the compactness to be qualified, immediately starting to maintain; natural health preserving is adopted; the life span is not less than 3 days.

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