CN109781620B - Asphalt cohesion determination method - Google Patents
Asphalt cohesion determination method Download PDFInfo
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- CN109781620B CN109781620B CN201910246050.0A CN201910246050A CN109781620B CN 109781620 B CN109781620 B CN 109781620B CN 201910246050 A CN201910246050 A CN 201910246050A CN 109781620 B CN109781620 B CN 109781620B
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Abstract
The invention discloses a method for measuring asphalt cohesion, which comprises the following steps: firstly, fixedly assembling an upper box and a lower box in the improved strain control type direct shear apparatus into a shear box, and coating an asphalt separant; secondly, heating the asphalt, pouring the heated asphalt into a shear box coated with an asphalt separant, cooling and preserving heat; thirdly, horizontally rolling the shear box filled with the asphalt after heat preservation and zeroing a force measuring dial indicator; pulling out a fixed bolt of the shear box, starting a stopwatch, simultaneously rotating a hand wheel at a constant speed, and observing and recording the maximum shear deformation reading of the asphalt; and fifthly, calculating the shear stress value when the asphalt is sheared and damaged, namely the asphalt cohesion. The shear box of the strain control type direct shear apparatus is improved to obtain the asphalt sample with the H-shaped longitudinal section, so that the internal stress and the stressed area of the asphalt sample are reduced, the asphalt damaged surface is prevented from being damaged by the action of vertical normal stress, the horizontal force in the cohesive force measuring process is reduced, the measuring difficulty is reduced, and the accuracy and the precision of the measuring result are improved.
Description
Technical Field
The invention belongs to the technical field of asphalt performance testing of highway engineering, and particularly relates to an asphalt cohesion determination method.
Background
Cohesive force, also called cohesive force, refers to the mutual attraction between adjacent parts in the same substance, which is the expression of molecular force existing between the molecules of the same substance, and therefore, cohesive force can also be considered as the shear strength of the substance without any normal stress on the failure surface. The cohesive force can lead the substances to be gathered into liquid or solid, and particularly in a liquid adhesion layer which is in contact with the solid, the liquid infiltrates the solid or does not infiltrate the solid due to the difference of the relative sizes of the cohesive force and the adhesion force. In the asphalt mixture, the bonding effect of asphalt and aggregate is the principle, so the strength of the asphalt mixture is not only related to the cohesive force of the asphalt binder and the internal friction resistance of mineral aggregate particles, but also related to the adhesion force of the asphalt and the aggregate. However, the main contribution is still the cohesive force of the bituminous binder and the magnitude of the frictional resistance in the mineral aggregate particles. However, to date, there has been no good method to directly test the cohesion of asphalt binders.
According to the method for measuring the cohesive force of the soil in the soil mechanics, the cohesive force can be obtained by deducting the friction strength from the total shear strength under the condition of effective stress. However, since most of the intensity envelopes are not linear, and the determination of the cohesion force by finding the intercept of the straight line segment of the extension is not precise, in many cases, the accurate determination of the cohesion force is difficult in a shear test under low or even no confining pressure (no normal stress).
In view of the above, the present invention is to find a simple, convenient and reliable method for measuring the cohesion of the asphalt fracture surface by a shear test without the vertical normal stress, based on the concept of cohesion.
Disclosure of Invention
The invention aims to solve the technical problem of providing a method for measuring the asphalt cohesion in order to overcome the defects of the prior art. According to the method, the shear box of the strain control type direct shear apparatus is improved based on the material characteristics of asphalt, so that an asphalt sample with an I-shaped longitudinal section is obtained, the internal stress of the asphalt sample and the stress area of the sample are reduced, the asphalt fracture surface is prevented from being sheared and damaged by the vertical normal stress, the horizontal force in the cohesive force measurement process is reduced, the measurement difficulty is reduced, and the accuracy and the precision of the measurement result are improved.
In order to solve the technical problems, the invention adopts the technical scheme that: the asphalt cohesion determination method is characterized by comprising the following steps:
firstly, aligning and matching an upper box 4 and a lower box 2 in an improved strain control type direct shear apparatus to assemble a shear box, and then coating an asphalt separant on the inner wall and the bottom surface of the shear box; the upper box is internally provided with a round hole which is formed by a large-diameter round hole and a small-diameter round hole in a through mode and has an inverted convex longitudinal section, the lower box is internally provided with a blind hole which is formed by a large-diameter round hole and a small-diameter round hole and has a convex longitudinal section, the inner diameters of the large-diameter round hole in the upper box and the large-diameter round hole in the lower box are the same, and the inner diameters of the small-diameter round hole in the upper box and the small-diameter round hole in the lower box are the;
step two, heating the asphalt to 140-160 ℃, pouring the asphalt into the shear box coated with the asphalt separant in the step one to the position of the scale mark, then placing the shear box at 20-25 ℃ for cooling for more than 1.5h, and then preserving the heat for 1.5-2.0 h at 60 ℃;
rotating a hand wheel to drive a pushing seat to push a lower box, so as to drive the heat-insulated shear box filled with the asphalt in the step two to roll along the horizontal direction until steel balls on an upper box contact a dynamometer, and then adjusting the reading of a dynamometer on the dynamometer to return to zero;
fourthly, pulling out a fixed bolt of the shear box, starting a stopwatch, simultaneously rotating a hand wheel at a constant speed and observing a pointer of the force-measuring dial indicator, when the pointer of the force-measuring dial indicator does not advance any more and retreats, the sample is sheared and damaged, the reading of the force-measuring dial indicator is recorded as the maximum shearing deformation reading of the asphalt, and when the pointer of the force-measuring dial indicator continuously advances along with the rotation of the hand wheel, the reading of the force-measuring dial indicator when the hand wheel rotates for 100 circles is specified as the maximum shearing deformation reading of the asphalt; the reading of the force measuring dial indicator is accurate to 0.01 mm;
step five, reversing the hand wheel to the original position, taking the shear box down, taking out the asphalt, cleaning the shear box, then returning the shear box to the original position, and then calculating the shear stress value when the asphalt is sheared and damaged, namely the asphalt cohesion tau is C according to the reading of the maximum asphalt shearing deformation obtained in the step fourd·RmWherein tau is asphalt cohesion and has the unit of kPa, CdThe calibration factor of the dynamometer is expressed in kPa/0.01mm, RmThe maximum shear deformation reading for bitumen is in units of 0.01 mm.
Correction coefficient C of dynamometer in step fivedThe specific value is determined by the shear ring in the strain control type direct shear apparatus.
The invention utilizes a strain control type direct shear apparatus to measure the cohesive force of asphalt, and shear and destroy an asphalt sample by applying horizontal force to obtain the shear stress value when the asphalt is shear and destroyed, namely the asphalt cohesive force, wherein the asphalt sample is shear and destroyed under the action of opposite horizontal force in the asphalt cohesive force measuring process, and the asphalt destruction surface is not subjected to the action of vertical normal stress. The invention improves the shear box of a strain control type direct shear apparatus based on the material characteristics of asphalt, improves the original upper box consisting of round holes into a structure consisting of large-diameter round holes and small-diameter round holes which are communicated with each other and have a longitudinal section in an inverted convex shape, improves the original lower box consisting of round holes into a blind hole structure consisting of large-diameter round holes and small-diameter round holes which are communicated with each other and have a convex shape, has the same inner diameter as the large-diameter round holes in the upper box and the small-diameter round holes in the lower box, has the same inner diameter as the small-diameter round holes in the upper box and the small-diameter round holes in the lower box, obtains the shear box with a cavity and an I-shaped longitudinal section, obtains an asphalt sample with an I-shaped longitudinal section, reduces the internal stress of the asphalt sample and the stressed area of the sample, reduces the horizontal force in the cohesive force measuring process, thereby reducing the measuring difficulty, improving the accuracy and the accuracy of the measuring result, and simultaneously reducing the horizontal force loading process of the cohesive force measurement, the asphalt sample is in danger of falling off from the round hole due to excessive viscosity.
In addition, because the strain control type direct shear apparatus is not provided with a temperature control device, the heat preservation process of the asphalt sample is carried out beside the strain control type direct shear apparatus so as to ensure that the asphalt sample can be immediately subjected to a shear test after being taken out from the heat preservation device, thereby reducing the influence of the temperature difference of the asphalt sample on the measurement process and further improving the accuracy of the measurement method.
The asphalt cohesion force measuring method is characterized in that in the step one, the inner diameters of the large round hole in the upper box and the large round hole in the lower box are both 40mm, the height of the large round hole in the upper box is 15mm, the height from the middle bottom surface of the large round hole to the scale mark is 10mm, the height of the large round hole in the lower box is 10mm, the inner diameters of the small round hole in the upper box and the small round hole in the lower box are both 20mm, and the heights of the small round hole in the upper box and the small round hole in the lower box are both 10 mm. The structural sizes of the upper box and the lower box ensure that the longitudinal section of the asphalt sample is in an I-shaped structure, and the structural sizes of the asphalt sample in the upper box and the asphalt sample in the lower box are completely consistent, so that the internal stress of the asphalt sample is further reduced, and the accuracy of a measurement result is improved; in addition, the shear box formed by the upper box and the lower box with the structural size can be suitable for most strain control type direct shear apparatuses, and the equipment application range of the method is expanded.
The method for measuring the cohesion of the asphalt is characterized in that the asphalt in the second step is base asphalt or modified asphalt. The determination method is suitable for common matrix asphalt or modified asphalt, and has wide application range and high practical value.
The method for measuring the cohesion of the asphalt is characterized in that the heat preservation in the step two is carried out by adopting water bath heat preservation or oven heat preservation. The heat preservation mode can accurately control the temperature, is convenient to control and is common, and the implementation difficulty of the method is further reduced.
The asphalt cohesion force measuring method is characterized in that the asphalt in the step two is heated and then poured into the shear box coated with the release agent slowly, and the heated asphalt is ensured to completely fill the large round hole of the lower box in the shear box. The operation avoids the phenomenon that gas is mixed into the heated asphalt to form a cavity in the big round hole of the lower box, so that the asphalt sample in the lower box is reduced in restriction force in the measuring process to cause falling off.
The asphalt cohesion force measuring method is characterized in that the measuring range of the dynamometer in the third step is 10mm, and the division value is 0.01 mm. The force measuring dial indicator with the specification is common, the measuring range and the division value both meet the requirements of the measuring process, and the easy realization degree of the method is further improved.
The asphalt cohesion force measuring method is characterized in that the rotating speed of the hand wheel in the fourth step is 10 s/week. The rotation speed is convenient to control, and the stability and reliability of the measuring result are ensured.
Compared with the prior art, the invention has the following advantages:
1. according to the invention, the shear box of the strain control type direct shear apparatus is improved based on the material characteristics of asphalt, so that the shear box with the box cavity having the H-shaped longitudinal section is obtained, and an asphalt sample with the H-shaped longitudinal section is obtained, thus the internal stress and the stress area of the asphalt sample are reduced, the asphalt damage surface is prevented from being sheared and damaged by the vertical normal stress, the horizontal force in the cohesive force measuring process is reduced, the measuring difficulty is reduced, the accuracy and the accuracy of the measuring result are improved, and the risk that the asphalt sample integrally falls off from the circular hole due to overlarge viscosity in the horizontal force loading process of the cohesive force measurement is reduced.
2. According to the invention, the structure of the shear box of the strain control type direct shear apparatus in the prior art is improved, so that the direct measurement of the asphalt cohesion is realized, the defects of the existing test method in the aspect of asphalt cohesion measurement are overcome, the measurement cost is effectively reduced, and the measurement method is simple and convenient to operate.
3. The measuring process conditions such as temperature and the rotating speed of the hand wheel are stable and controllable, so that the cohesion of different types of asphalt can be tested by selecting uniform process conditions, the evaluation of the cohesion of different types of asphalt is facilitated, the accuracy and the reliability of the test result are improved, and the cohesion test result of different types of asphalt has comparability.
The technical solution of the present invention is further described in detail by the accompanying drawings and examples.
Drawings
Fig. 1 is a front sectional view of an improved strain-controlled direct shear apparatus used in the present invention.
Fig. 2 is a top cross-sectional view of a shearing system of the improved strain-controlled direct shear employed in the present invention.
Figure 3 is a top view of the force measuring system of the improved strain-controlled direct shear employed in the present invention.
Description of the reference numerals
1-a pushing seat; 2, placing the box; 3-asphalt;
4, loading the box; 5-a dynamometer; 6-dynamometer dial gauge;
7-bolt hole; 8, a hand wheel; 9-the ball.
Detailed Description
As shown in fig. 1, 2 and 3, the improved strain control type direct shear apparatus adopted by the invention comprises a shearing system and a force measuring system, wherein a shear box used for containing asphalt 3 in the shearing system is composed of a lower box 2 and an upper box 4 which are matched with each other, the lower box 2 and the upper box 4 are respectively and correspondingly provided with a bolt hole 7, a fixing bolt penetrates through the bolt hole 7 to fixedly connect the lower box 2 and the upper box 4, a ball 9 is arranged at the bottom of the shear box, the shear box horizontally rolls under the action of a rotating hand wheel 8, and the force measuring system comprises a force measuring meter 5 and a dial indicator 6 arranged on the force measuring meter 5. The working principle of the improved strain control type direct shear apparatus adopted by the invention for measuring the asphalt cohesion is as follows: the pushing seat 1 is driven to act on the lower box 2 of the shear box by rotating the hand wheel 8, and force is applied to the lower box 2 of the shear box from the horizontal direction, so that the shear box filled with asphalt is driven to roll along the horizontal direction, steel balls on the upper box 4 are contacted and pushed against the dynamometer 5, the action direction of the horizontal force applied to the lower box 2 is opposite to the action direction of the dynamometer 5 on the upper box 4, so that the upper box 4 and the lower box 2 move in the reverse direction along the same straight line direction, the asphalt in the shear box bears the action of the shearing force generated by the reverse movement of the upper box 4 and the lower box 2 until the asphalt is damaged under the action of the shearing force, and the maximum asphalt shearing deformation reading is obtained according to the reading of the force dial indicator 6.
Example 1
The method of the embodiment comprises the following steps:
aligning and matching an upper box 4 and a lower box 2 in an improved strain control type direct shear instrument, inserting a fixed bolt into a corresponding bolt hole 7 to assemble a shear box, and then coating an asphalt separant on the inner wall and the bottom surface of the shear box; the upper box 4 is internally provided with a round hole which is formed by a large-diameter round hole and a small-diameter round hole in a through mode and has a reverse convex-shaped longitudinal section, and the lower box 2 is internally provided with a blind hole which is formed by a large-diameter round hole and a small-diameter round hole and has a convex-shaped longitudinal section; the inner diameters of the large round hole in the upper box 4 and the large round hole in the lower box 2 are both 40mm, the height of the large round hole in the upper box 4 is 15mm, the height of the scale mark in the large round hole is 10mm, the height of the large round hole in the lower box 2 is 10mm, the inner diameters of the small round hole in the upper box 4 and the small round hole in the lower box 2 are both 20mm, and the heights are both 10 mm; the asphalt separant is prepared from talcum powder and glycerol according to the weight ratio of 1: 1 by mass ratio;
step two, heating the No. 50 matrix asphalt to 140 ℃, slowly pouring the heated No. 50 matrix asphalt into the shear box coated with the asphalt separant in the step one to the scale mark, ensuring that the heated No. 50 matrix asphalt completely fills the large round hole of the lower box 2 in the shear box, then placing the shear box at 20 ℃ for cooling for 1.5h, and then preserving the heat for 1.5h under the water bath heat preservation condition of 60 ℃;
step three, rotating a hand wheel 8 to drive a pushing seat 1 to push a lower box 2, driving the shear box filled with the 50# matrix asphalt after heat preservation in the step two to roll along the horizontal direction until steel balls on an upper box 4 contact a dynamometer 5, and then adjusting the reading of a dynamometer 6 on the dynamometer 5 to return to zero; the measuring range of the force measuring dial indicator 6 is 10mm, and the division value is 0.01 mm;
fourthly, pulling out a fixed bolt of the shear box, starting a stopwatch, simultaneously rotating a hand wheel 8 at a constant speed at a rotation speed of 10 s/week and observing a pointer of the dynamometer 6, when the pointer of the dynamometer 6 does not advance any more and retreats, the sample is sheared and damaged, the sample rotates for 85 weeks in total, and the reading of the dynamometer 6 is recorded as the maximum shear deformation reading of No. 50 matrix asphalt, which is 385(0.01 mm);
step five, reversing the hand wheel 8 to the original position, taking the shear box down, taking out the 50# matrix asphalt, cleaning the shear box, putting the shear box back to the original position, and calculating the shear stress value when the 50# matrix asphalt is sheared and damaged, namely the cohesive force tau of the 50# matrix asphalt is C according to the maximum shear deformation reading of the 50# matrix asphalt obtained in the step fourd·Rm1.918kPa/0.01mm × 385.00(0.01mm) ═ 0.738 MPa-738 kPa, where τ is 50# base asphalt cohesion in kPa, CdThe calibration factor of the dynamometer is expressed in kPa/0.01mm, RmThe maximum shear deformation reading is 50# base asphalt, with the unit of 0.01 mm.
Example 2
The method of the embodiment comprises the following steps:
aligning and matching an upper box 4 and a lower box 2 in an improved strain control type direct shear instrument, inserting a fixed bolt into a corresponding bolt hole 7 to assemble a shear box, and then coating an asphalt separant on the inner wall and the bottom surface of the shear box; the upper box 4 is internally provided with a round hole which is formed by a large-diameter round hole and a small-diameter round hole in a through mode and has a reverse convex-shaped longitudinal section, and the lower box 2 is internally provided with a blind hole which is formed by a large-diameter round hole and a small-diameter round hole and has a convex-shaped longitudinal section; the inner diameters of the large round hole in the upper box 4 and the large round hole in the lower box 2 are both 40mm, the height of the large round hole in the upper box 4 is 15mm, the height from the bottom surface of the large round hole to the scale mark is 10mm, the height of the large round hole in the lower box 2 is 10mm, the inner diameters of the small round hole in the upper box 4 and the small round hole in the lower box 2 are both 20mm, and the heights of the small round hole and the small round hole are both 10 mm; the asphalt separant is prepared from talcum powder and glycerol according to the weight ratio of 1: 1 by mass ratio;
step two, heating the No. 50 matrix asphalt to 150 ℃, slowly pouring the heated No. 50 matrix asphalt into the shear box coated with the asphalt separant in the step one to the scale mark, ensuring that the heated No. 50 matrix asphalt completely fills the large round hole of the lower box 2 in the shear box, then placing the shear box at 22 ℃ for cooling for 2 hours, and then preserving the heat for 2 hours under the water bath heat preservation condition of 60 ℃;
step three, rotating a hand wheel 8 to drive a pushing seat 1 to push a lower box 2, driving the shear box filled with the 50# matrix asphalt after heat preservation in the step two to roll along the horizontal direction until steel balls on an upper box 4 contact a dynamometer 5, and then adjusting the reading of a dynamometer 6 on the dynamometer 5 to return to zero; the measuring range of the force measuring dial indicator 6 is 10mm, and the division value is 0.01 mm;
fourthly, pulling out a fixed bolt of the shear box, starting a stopwatch, simultaneously rotating a hand wheel 8 at a constant speed of 10 s/week and observing a pointer of the dynamometer 6, when the pointer of the dynamometer 6 does not advance any more and retreats, the sample is sheared and damaged, the sample rotates for 85 weeks in total, and the reading of the dynamometer 6 is recorded as the maximum shear deformation reading of No. 50 matrix asphalt, which is 377.00(0.01 mm);
step five, reversing the hand wheel 8 to the original position, taking the shear box down, taking out the 50# matrix asphalt, cleaning the shear box, putting the shear box back to the original position, and calculating the shear stress value when the 50# matrix asphalt is sheared and damaged, namely the cohesive force tau of the 50# matrix asphalt is C according to the maximum shear deformation reading of the 50# matrix asphalt obtained in the step fourd·Rm1.918kPa/0.01mm × 377.00(0.01mm) ═ 0.723MPa 723kPa, where τ is 50# base asphalt cohesion in kPa, CdThe calibration factor of the dynamometer is expressed in kPa/0.01mm, RmThe maximum shear deformation reading is 50# base asphalt, with the unit of 0.01 mm.
Example 3
The method of the embodiment comprises the following steps:
aligning and matching an upper box 4 and a lower box 2 in an improved strain control type direct shear instrument, inserting a fixed bolt into a corresponding bolt hole 7 to assemble a shear box, and then coating an asphalt separant on the inner wall and the bottom surface of the shear box; the upper box 4 is internally provided with a round hole which is formed by a large-diameter round hole and a small-diameter round hole in a through mode and has a reverse convex-shaped longitudinal section, and the lower box 2 is internally provided with a blind hole which is formed by a large-diameter round hole and a small-diameter round hole and has a convex-shaped longitudinal section; the inner diameters of the large round hole in the upper box 4 and the large round hole in the lower box 2 are both 40mm, the height of the large round hole in the upper box 4 is 15mm, the height from the bottom surface of the large round hole to the scale mark is 10mm, the height of the large round hole in the lower box 2 is 10mm, the inner diameters of the small round hole in the upper box 4 and the small round hole in the lower box 2 are both 20mm, and the heights of the small round hole and the small round hole are both 10 mm; the asphalt insulation is prepared from talcum powder and glycerol according to the weight ratio of 1: 1 by mass ratio;
step two, heating the No. 50 matrix asphalt to 160 ℃, slowly pouring the heated No. 50 matrix asphalt into the shear box coated with the asphalt separant in the step one to the scale mark, ensuring that the heated No. 50 matrix asphalt completely fills the large round hole of the lower box 2 in the shear box, then placing the shear box at 25 ℃ for cooling for 2 hours, and then preserving the heat for 2 hours under the water bath heat preservation condition of 59.5-60.5 ℃;
step three, rotating a hand wheel 8 to drive a pushing seat 1 to push a lower box 2, driving the shear box filled with the 50# matrix asphalt after heat preservation in the step two to roll along the horizontal direction until steel balls on an upper box 4 contact a dynamometer 5, and then adjusting the reading of a dynamometer 6 on the dynamometer 5 to return to zero; the measuring range of the force measuring dial indicator 6 is 10mm, and the division value is 0.01 mm;
fourthly, pulling out a fixed bolt of the shear box, starting a stopwatch, simultaneously rotating a hand wheel 8 at a constant speed of 10 s/week and observing a pointer of the dynamometer 6, when the pointer of the dynamometer 6 does not advance any more and retreats, the sample is sheared and damaged, rotating for 83 weeks in total, and recording the reading of the dynamometer 6 as the maximum shear deformation reading of No. 50 matrix asphalt, which is 382.00(0.01 mm);
step five, reversing the hand wheel 8 to the original position, taking the shear box down, taking out the 50# matrix asphalt, cleaning the shear box, putting the shear box back to the original position, and calculating the shear stress value when the 50# matrix asphalt is sheared and damaged, namely the cohesive force tau of the 50# matrix asphalt is C according to the maximum shear deformation reading of the 50# matrix asphalt obtained in the step fourd·Rm1.918kPa/0.01mm × 382.00(0.01mm) ═ 732 kPa/0.732 MPa, where τ is 50# base asphalt cohesion in kPa, CdThe calibration factor of the dynamometer is expressed in kPa/0.01mm, RmThe maximum shear deformation reading is 50# base asphalt, with the unit of 0.01 mm.
Example 4
The method of the embodiment comprises the following steps:
aligning and matching an upper box 4 and a lower box 2 in an improved strain control type direct shear instrument, inserting a fixed bolt into a corresponding bolt hole 7 to assemble a shear box, and then coating an asphalt separant on the inner wall and the bottom surface of the shear box; the upper box 4 is internally provided with a round hole which is formed by a large-diameter round hole and a small-diameter round hole in a through mode and has a reverse convex-shaped longitudinal section, and the lower box 2 is internally provided with a blind hole which is formed by a large-diameter round hole and a small-diameter round hole and has a convex-shaped longitudinal section; the inner diameters of the large round hole in the upper box 4 and the large round hole in the lower box 2 are both 40mm, the height of the large round hole in the upper box 4 is 15mm, the height from the bottom surface of the large round hole to the scale mark is 10mm, the height of the large round hole in the lower box 2 is 10mm, the inner diameters of the small round hole in the upper box 4 and the small round hole in the lower box 2 are both 20mm, and the heights of the small round hole and the small round hole are both 10 mm; the asphalt separant is prepared from talcum powder and glycerol according to the weight ratio of 1: 1 by mass ratio;
step two, heating the No. 70 matrix asphalt to 140 ℃, slowly pouring the heated No. 70 matrix asphalt into the shear box coated with the asphalt separant in the step one to the scale mark, ensuring that the heated No. 70 matrix asphalt completely fills the large round hole of the lower box 2 in the shear box, then placing the shear box at 22 ℃ for cooling for 1.6h, and then preserving the heat for 1.5h under the water bath heat preservation condition of 60 ℃;
step three, rotating a hand wheel 8 to drive a pushing seat 1 to push a lower box 2, driving the shear box filled with the 70# matrix asphalt after heat preservation in the step two to roll along the horizontal direction until steel balls on an upper box 4 contact a dynamometer 5, and then adjusting the reading of a dynamometer 6 on the dynamometer 5 to return to zero; the measuring range of the force measuring dial indicator 6 is 10mm, and the division value is 0.01 mm;
fourthly, pulling out a fixed bolt of the shear box, starting a stopwatch, simultaneously rotating a hand wheel 8 at a constant speed of 10 s/week and observing a pointer of the dynamometer 6, when the pointer of the dynamometer 6 does not advance any more and retreats, the sample is sheared and damaged, the sample rotates for 77 weeks in total, and the reading of the dynamometer 6 is recorded as the maximum shear deformation reading of No. 70 matrix asphalt, wherein the maximum shear deformation reading is 340.00(0.01 mm);
step five, reversing the hand wheel 8 to the original position, taking the shear box down, taking out the 70# matrix asphalt, cleaning the shear box, putting the shear box back to the original position, and calculating the shear stress value when the 70# matrix asphalt is sheared and damaged, namely the cohesive force tau of the 70# matrix asphalt is C according to the maximum shear deformation reading of the 70# matrix asphalt obtained in the step fourd·Rm1.918kPa/0.01mm × 340.00(0.01mm) ═ 652kPa (0.652 MPa), where τ is 70# base asphalt cohesion in kPa, CdThe calibration factor of the dynamometer is expressed in kPa/0.01mm, RmThe maximum shear deformation reading is given in 0.01mm for No. 70 base asphalt.
Example 5
The method of the embodiment comprises the following steps:
aligning and matching an upper box 4 and a lower box 2 in an improved strain control type direct shear instrument, inserting a fixed bolt into a corresponding bolt hole 7 to assemble a shear box, and then coating an asphalt separant on the inner wall and the bottom surface of the shear box; the upper box 4 is internally provided with a round hole which is formed by a large-diameter round hole and a small-diameter round hole in a through mode and has a reverse convex-shaped longitudinal section, and the lower box 2 is internally provided with a blind hole which is formed by a large-diameter round hole and a small-diameter round hole and has a convex-shaped longitudinal section; the inner diameters of the large round hole in the upper box 4 and the large round hole in the lower box 2 are both 40mm, the height of the large round hole in the upper box 4 is 15mm, the height from the bottom surface of the large round hole to the scale mark is 10mm, the height of the large round hole in the lower box 2 is 10mm, the inner diameters of the small round hole in the upper box 4 and the small round hole in the lower box 2 are both 20mm, and the heights of the small round hole and the small round hole are both 10 mm; the asphalt separant is prepared from talcum powder and glycerol according to the weight ratio of 1: 1 by mass ratio;
step two, heating the No. 70 matrix asphalt to 150 ℃, slowly pouring the heated No. 70 matrix asphalt into the shear box coated with the asphalt separant in the step one to the scale mark, ensuring that the heated No. 70 matrix asphalt completely fills the large round hole of the lower box 2 in the shear box, then placing the shear box at 25 ℃ for cooling for 1.5h, and then preserving the heat for 1.6h under the water bath heat preservation condition of 60 ℃;
step three, rotating a hand wheel 8 to drive a pushing seat 1 to push a lower box 2, driving the shear box filled with the 70# matrix asphalt after heat preservation in the step two to roll along the horizontal direction until steel balls on an upper box 4 contact a dynamometer 5, and then adjusting the reading of a dynamometer 6 on the dynamometer 5 to return to zero; the measuring range of the force measuring dial indicator 6 is 10mm, and the division value is 0.01 mm;
fourthly, pulling out a fixed bolt of the shear box, starting a stopwatch, simultaneously rotating a hand wheel 8 at a constant speed of 10 s/week and observing a pointer of the dynamometer 6, when the pointer of the dynamometer 6 does not advance any more and retreats, the sample is sheared and damaged, rotating for 74 weeks in total, and recording the reading of the dynamometer 6 as the maximum shear deformation reading of No. 70 matrix asphalt, which is 331.00(0.01 mm);
step five, reversing the hand wheel 8 to the original position, taking the shear box down, taking out the 70# matrix asphalt, cleaning the shear box, putting the shear box back to the original position, and calculating the shear stress value when the 70# matrix asphalt is sheared and damaged, namely the cohesive force tau of the 70# matrix asphalt is C according to the maximum shear deformation reading of the 70# matrix asphalt obtained in the step fourd·Rm1.918kPa/0.01mm × 331.00(0.01mm) ═ 635 kPa/0.635 MPa, where τ is the cohesion of No. 70 base asphalt in kPa, CdThe calibration factor of the dynamometer is expressed in kPa/0.01mm, RmThe maximum shear deformation reading is given in 0.01mm for No. 70 base asphalt.
Example 6
The method of the embodiment comprises the following steps:
aligning and matching an upper box 4 and a lower box 2 in an improved strain control type direct shear instrument, inserting a fixed bolt into a corresponding bolt hole 7 to assemble a shear box, and then coating an asphalt separant on the inner wall and the bottom surface of the shear box; the upper box 4 is internally provided with a round hole which is formed by a large-diameter round hole and a small-diameter round hole in a through mode and has a reverse convex-shaped longitudinal section, and the lower box 2 is internally provided with a blind hole which is formed by a large-diameter round hole and a small-diameter round hole and has a convex-shaped longitudinal section; the inner diameters of the large round hole in the upper box 4 and the large round hole in the lower box 2 are both 40mm, the height of the large round hole in the upper box 4 is 15mm, the height from the bottom surface of the large round hole to the scale mark is 10mm, the height of the large round hole in the lower box 2 is 10mm, the inner diameters of the small round hole in the upper box 4 and the small round hole in the lower box 2 are both 20mm, and the heights of the small round hole and the small round hole are both 10 mm; the asphalt separant is prepared from talcum powder and glycerol according to the weight ratio of 1: 1 by mass ratio;
step two, heating the No. 70 matrix asphalt to 160 ℃, slowly pouring the heated No. 70 matrix asphalt into the shear box coated with the asphalt separant in the step one to the scale mark, ensuring that the heated No. 70 matrix asphalt completely fills the large round hole of the lower box 2 in the shear box, then placing the shear box at 20 ℃ for cooling for 2 hours, and then preserving the heat for 2 hours under the water bath heat preservation condition of 60 ℃;
step three, rotating a hand wheel 8 to drive a pushing seat 1 to push a lower box 2, driving the shear box filled with the 70# matrix asphalt after heat preservation in the step two to roll along the horizontal direction until steel balls on an upper box 4 contact a dynamometer 5, and then adjusting the reading of a dynamometer 6 on the dynamometer 5 to return to zero; the measuring range of the force measuring dial indicator 6 is 10mm, and the division value is 0.01 mm;
fourthly, pulling out a fixed bolt of the shear box, starting a stopwatch, simultaneously rotating a hand wheel 8 at a constant speed of 10 s/week and observing a pointer of the dynamometer 6, when the pointer of the dynamometer 6 does not advance any more and retreats, the sample is sheared and damaged, the sample rotates for 72 weeks in total, and the reading of the dynamometer 6 is recorded as the maximum shear deformation reading of No. 70 matrix asphalt, which is 324.00(0.01 mm);
step five, reversing the hand wheel 8 to the original position, taking the shear box down, taking out the 70# matrix asphalt, cleaning the shear box, putting the shear box back to the original position, and calculating the shear stress value when the 70# matrix asphalt is sheared and damaged, namely the cohesive force tau of the 70# matrix asphalt is C according to the maximum shear deformation reading of the 70# matrix asphalt obtained in the step fourd·Rm1.918kPa/0.01mm × 324.00(0.01mm) ═ 621 kPa/0.621 MPa, where τ is the cohesion of No. 70 base asphalt in kPa, CdThe calibration factor of the dynamometer is expressed in kPa/0.01mm, RmThe maximum shear deformation reading is given in 0.01mm for No. 70 base asphalt.
Example 7
The method of the embodiment comprises the following steps:
aligning and matching an upper box 4 and a lower box 2 in an improved strain control type direct shear instrument, inserting a fixed bolt into a corresponding bolt hole 7 to assemble a shear box, and then coating an asphalt separant on the inner wall and the bottom surface of the shear box; the upper box 4 is internally provided with a round hole which is formed by a large-diameter round hole and a small-diameter round hole in a through mode and has a reverse convex-shaped longitudinal section, and the lower box 2 is internally provided with a blind hole which is formed by a large-diameter round hole and a small-diameter round hole and has a convex-shaped longitudinal section; the inner diameters of the large round hole in the upper box 4 and the large round hole in the lower box 2 are both 40mm, the height of the large round hole in the upper box 4 is 15mm, the height from the bottom surface of the large round hole to the scale mark is 10mm, the height of the large round hole in the lower box 2 is 10mm, the inner diameters of the small round hole in the upper box 4 and the small round hole in the lower box 2 are both 20mm, and the heights of the small round hole and the small round hole are both 10 mm; the asphalt is isolated from the asphalt by talcum powder and glycerol according to the weight ratio of 1: 1 by mass ratio;
step two, heating the 90# matrix asphalt to 140 ℃, slowly pouring the heated 90# matrix asphalt into the shear box coated with the asphalt separant in the step one to the scale mark, ensuring that the heated 90# matrix asphalt completely fills the large round hole of the lower box 2 in the shear box, then placing the shear box at 25 ℃ for cooling for 2 hours, and then preserving the heat for 2 hours under the water bath heat preservation condition of 60 ℃;
step three, rotating a hand wheel 8 to drive a pushing seat 1 to push a lower box 2, driving the shear box filled with the 90# matrix asphalt after heat preservation in the step two to roll along the horizontal direction until steel balls on an upper box 4 contact a dynamometer 5, and then adjusting the reading of a dynamometer 6 on the dynamometer 5 to return to zero; the measuring range of the force measuring dial indicator 6 is 10mm, and the division value is 0.01 mm;
fourthly, pulling out a fixed bolt of the shear box, starting a stopwatch, simultaneously rotating a hand wheel 8 at a constant speed of 10 s/week and observing a pointer of the dynamometer 6, when the pointer of the dynamometer 6 does not advance any more and retreats, the sample is sheared and damaged, the sample rotates for 59 weeks in total, and the reading of the dynamometer 6 is recorded as the maximum shear deformation reading of 90# matrix asphalt, namely 312.00(0.01 mm);
step five, reversing the hand wheel 8 to the original position, taking the shear box down, taking out the 90# matrix asphalt, cleaning the shear box, putting the shear box back to the original position, and then obtaining the 90# matrix asphalt according to the step fourThe maximum shear deformation reading is carried out, and the shear stress value when the 90# matrix asphalt is in shear failure, namely the 90# matrix asphalt cohesion force tau is calculated to be Cd·Rm1.918kPa/0.01mm × 312.00(0.01mm) ═ 598 kPa/0.598 MPa, where τ is 90# base asphalt cohesion in kPa, CdThe calibration factor of the dynamometer is expressed in kPa/0.01mm, RmThe maximum shear deformation reading is given in units of 0.01mm for # 90 base asphalt.
Example 8
The method of the embodiment comprises the following steps:
aligning and matching an upper box 4 and a lower box 2 in an improved strain control type direct shear instrument, inserting a fixed bolt into a corresponding bolt hole 7 to assemble a shear box, and then coating an asphalt separant on the inner wall and the bottom surface of the shear box; the upper box 4 is internally provided with a round hole which is formed by a large-diameter round hole and a small-diameter round hole in a through mode and has a reverse convex-shaped longitudinal section, and the lower box 2 is internally provided with a blind hole which is formed by a large-diameter round hole and a small-diameter round hole and has a convex-shaped longitudinal section; the inner diameters of the large round hole in the upper box 4 and the large round hole in the lower box 2 are both 40mm, the height of the large round hole in the upper box 4 is 15mm, the height from the bottom surface of the large round hole to the scale mark is 10mm, the height of the large round hole in the lower box 2 is 10mm, the inner diameters of the small round hole in the upper box 4 and the small round hole in the lower box 2 are both 20mm, and the heights of the small round hole and the small round hole are both 10 mm; the asphalt separant is prepared from talcum powder and glycerol according to the weight ratio of 1: 1 by mass ratio;
step two, heating the 90# matrix asphalt to 150 ℃, slowly pouring the heated 90# matrix asphalt into the shear box coated with the asphalt separant in the step one to the scale mark, ensuring that the heated 90# matrix asphalt completely fills the large round hole of the lower box 2 in the shear box, then placing the shear box at 20 ℃ for cooling for 2 hours, and then preserving the heat for 2 hours under the water bath heat preservation condition of 60 ℃;
step three, rotating a hand wheel 8 to drive a pushing seat 1 to push a lower box 2, driving the shear box filled with the 90# matrix asphalt after heat preservation in the step two to roll along the horizontal direction until steel balls on an upper box 4 contact a dynamometer 5, and then adjusting the reading of a dynamometer 6 on the dynamometer 5 to return to zero; the measuring range of the force measuring dial indicator 6 is 10mm, and the division value is 0.01 mm;
fourthly, pulling out a fixed bolt of the shear box, starting a stopwatch, simultaneously rotating a hand wheel 8 at a constant speed at a rotation speed of 10 s/week and observing a pointer of the dynamometer 6, when the pointer of the dynamometer 6 does not advance any more and retreats, the sample is sheared and damaged, rotating for 55 weeks totally, and recording the reading of the dynamometer 6 as the maximum shear deformation reading of 90# matrix asphalt to be 305.00(0.01 mm);
step five, reversing the hand wheel 8 to the original position, taking the shear box down, taking out the No. 50 matrix asphalt, cleaning the shear box, putting the shear box back to the original position, and calculating the shear stress value when the No. 90 matrix asphalt is sheared and damaged, namely the cohesive force tau of the No. 90 matrix asphalt is C according to the maximum shear deformation reading of the No. 90 matrix asphalt obtained in the step fourd·Rm1.918kPa/0.01mm × 305.00(0.01mm) ═ 585kPa (0.585 MPa), where τ is 90# base asphalt cohesion in kPa, CdThe calibration factor of the dynamometer is expressed in kPa/0.01mm, RmThe maximum shear deformation reading is given in units of 0.01mm for # 90 base asphalt.
Example 9
The method of the embodiment comprises the following steps:
aligning and matching an upper box 4 and a lower box 2 in an improved strain control type direct shear instrument, inserting a fixed bolt into a corresponding bolt hole 7 to assemble a shear box, and then coating an asphalt separant on the inner wall and the bottom surface of the shear box; the upper box 4 is internally provided with a round hole which is formed by a large-diameter round hole and a small-diameter round hole in a through mode and has a reverse convex-shaped longitudinal section, and the lower box 2 is internally provided with a blind hole which is formed by a large-diameter round hole and a small-diameter round hole and has a convex-shaped longitudinal section; the inner diameters of the large round hole in the upper box 4 and the large round hole in the lower box 2 are both 40mm, the height of the large round hole in the upper box 4 is 15mm, the height from the bottom surface of the large round hole to the scale mark is 10mm, the height of the large round hole in the lower box 2 is 10mm, the inner diameters of the small round hole in the upper box 4 and the small round hole in the lower box 2 are both 20mm, and the heights of the small round hole and the small round hole are both 10 mm; the asphalt separant is prepared from talcum powder and glycerol according to the weight ratio of 1: 1 by mass ratio;
step two, heating the 90# matrix asphalt to 160 ℃, slowly pouring the heated 90# matrix asphalt into the shear box coated with the asphalt separant in the step one to the scale mark, ensuring that the heated 90# matrix asphalt completely fills the large round hole of the lower box 2 in the shear box, then placing the shear box at 22 ℃ for cooling for 1.5 hours, and then preserving the heat for 1.5 hours under the water bath heat preservation condition of 60 ℃;
step three, rotating a hand wheel 8 to drive a pushing seat 1 to push a lower box 2, driving the shear box filled with the 90# matrix asphalt after heat preservation in the step two to roll along the horizontal direction until steel balls on an upper box 4 contact a dynamometer 5, and then adjusting the reading of a dynamometer 6 on the dynamometer 5 to return to zero; the measuring range of the force measuring dial indicator 6 is 10mm, and the division value is 0.01 mm;
fourthly, pulling out a fixed bolt of the shear box, starting a stopwatch, simultaneously rotating a hand wheel 8 at a constant speed of 10 s/week and observing a pointer of the dynamometer 6, when the pointer of the dynamometer 6 does not advance any more and retreats, the sample is sheared and damaged, the rotation is carried out for 61 weeks totally, and the reading of the dynamometer 6 is recorded as the maximum shear deformation reading of No. 50 matrix asphalt, which is 318.00(0.01 mm);
step five, reversing the hand wheel 8 to the original position, taking the shear box down, taking out the 90# matrix asphalt, cleaning the shear box, putting the shear box back to the original position, and calculating the shear stress value when the 90# matrix asphalt is sheared and damaged, namely the cohesive force tau of the 90# matrix asphalt is C according to the maximum shear deformation reading of the 90# matrix asphalt obtained in the step fourd·Rm1.918kPa/0.01mm × 318.00(0.01mm) ═ 610 kPa/0.610 MPa, where τ is 90# base asphalt cohesion in kPa, CdThe calibration factor of the dynamometer is expressed in kPa/0.01mm, RmThe maximum shear deformation reading is given in units of 0.01mm for # 90 base asphalt.
Example 10
The method of the embodiment comprises the following steps:
aligning and matching an upper box 4 and a lower box 2 in an improved strain control type direct shear instrument, inserting a fixed bolt into a corresponding bolt hole 7 to assemble a shear box, and then coating an asphalt separant on the inner wall and the bottom surface of the shear box; the upper box 4 is internally provided with a round hole which is formed by a large-diameter round hole and a small-diameter round hole in a through mode and has a reverse convex-shaped longitudinal section, and the lower box 2 is internally provided with a blind hole which is formed by a large-diameter round hole and a small-diameter round hole and has a convex-shaped longitudinal section; the inner diameters of the large round hole in the upper box 4 and the large round hole in the lower box 2 are both 40mm, the height of the large round hole in the upper box 4 is 15mm, the height from the bottom surface of the large round hole to the scale mark is 10mm, the height of the large round hole in the lower box 2 is 10mm, the inner diameters of the small round hole in the upper box 4 and the small round hole in the lower box 2 are both 20mm, and the heights of the small round hole and the small round hole are both 10 mm; the asphalt separant is prepared from talcum powder and glycerol according to the weight ratio of 1: 2 in a mass ratio;
step two, heating SBS modified asphalt to 140 ℃, slowly pouring the SBS modified asphalt into the shear box coated with the asphalt separant in the step one to the scale mark, ensuring that the heated SBS modified asphalt completely fills the large round hole of the lower box 2 in the shear box, then placing the shear box at 20 ℃ for cooling for 1.5h, and then preserving the heat for 1.5h under the condition of 60 ℃ oven heat preservation;
step three, rotating a hand wheel 8 to drive a pushing seat 1 to push a lower box 2, driving the shear box filled with SBS modified asphalt after heat preservation in the step two to roll along the horizontal direction until steel balls on an upper box 4 contact a dynamometer 5, and then adjusting the reading of a dynamometer 6 on the dynamometer 5 to return to zero; the measuring range of the force measuring dial indicator 6 is 10mm, and the division value is 0.01 mm;
fourthly, pulling out a fixed bolt of the shear box, starting a stopwatch, simultaneously rotating the hand wheel 8 at a constant speed of 10 s/week and observing a pointer of the force measurement dial indicator 6, and when the pointer of the force measurement dial indicator 6 continuously advances along with the rotation of the hand wheel 8, setting the reading of the force measurement dial indicator 6 when the hand wheel 8 rotates for 100 weeks as the maximum shear deformation reading 392.00(0.01mm) of the SBS modified asphalt;
step five, the hand wheel 8 is reversed to the original position, then the shear box is taken down and the SBS modified asphalt is taken out, the shear box is cleaned and then is put back to the original position, and then the shear stress value when the SBS modified asphalt is sheared and damaged, namely the adhesive force tau of the SBS modified asphalt is calculated according to the maximum shear deformation reading of the SBS modified asphalt obtained in the step fourd·Rm1.918kPa/0.01mm × 392.00(0.01mm) ═ 752 kPa/0.752 MPa, where τ is SBS modified asphalt cohesion in kPa, CdThe calibration factor of the dynamometer is expressed in kPa/0.01mm, RmThe maximum shear deformation reading for SBS modified asphalt is in units of 0.01 mm.
Example 11
The method of the embodiment comprises the following steps:
aligning and matching an upper box 4 and a lower box 2 in an improved strain control type direct shear instrument, inserting a fixed bolt into a corresponding bolt hole 7 to assemble a shear box, and then coating an asphalt separant on the inner wall and the bottom surface of the shear box; the upper box 4 is internally provided with a round hole which is formed by a large-diameter round hole and a small-diameter round hole in a through mode and has a reverse convex-shaped longitudinal section, and the lower box 2 is internally provided with a blind hole which is formed by a large-diameter round hole and a small-diameter round hole and has a convex-shaped longitudinal section; the inner diameters of the large round hole in the upper box 4 and the large round hole in the lower box 2 are both 40mm, the height of the large round hole in the upper box 4 is 15mm, the height from the bottom surface of the large round hole to the scale mark is 10mm, the height of the large round hole in the lower box 2 is 10mm, the inner diameters of the small round hole in the upper box 4 and the small round hole in the lower box 2 are both 20mm, and the heights of the small round hole and the small round hole are both 10 mm; the asphalt separant is prepared from talcum powder and glycerol according to the weight ratio of 1: 2 in a mass ratio;
step two, heating SBS modified asphalt to 150 ℃, slowly pouring the heated SBS modified asphalt into the shear box coated with the asphalt separant in the step one to the scale mark, ensuring that the heated SBS modified asphalt completely fills the large round hole of the lower box 2 in the shear box, then placing the shear box at 22 ℃ for cooling for 2 hours, and then preserving the heat for 2 hours under the condition of 60 ℃ oven heat preservation;
step three, rotating a hand wheel 8 to drive a pushing seat 1 to push a lower box 2, driving the shear box filled with SBS modified asphalt after heat preservation in the step two to roll along the horizontal direction until steel balls on an upper box 4 contact a dynamometer 5, and then adjusting the reading of a dynamometer 6 on the dynamometer 5 to return to zero; the measuring range of the force measuring dial indicator 6 is 10mm, and the division value is 0.01 mm;
fourthly, pulling out a fixed bolt of the shear box, starting a stopwatch, simultaneously rotating the hand wheel 8 at a constant speed of 10 s/week and observing a pointer of the force measurement dial indicator 6, and when the pointer of the force measurement dial indicator 6 continuously advances along with the rotation of the hand wheel 8, setting the reading of the force measurement dial indicator 6 when the hand wheel 8 rotates for 100 weeks as the maximum shear deformation reading 387.00(0.01mm) of the SBS modified asphalt;
step five, reversing the hand wheel 8 back to the original position, taking down the shear box and taking out the SBS for modificationCleaning the shear box, putting the asphalt back to the original position, and calculating the shear stress value, namely the adhesive force tau of the SBS modified asphalt, which is the shear failure of the SBS modified asphalt according to the maximum shear deformation reading of the SBS modified asphalt obtained in the fourth stepd·Rm1.918kPa/0.01mm × 387.00(0.01mm) ═ 742kPa (0.742 MPa), wherein tau is SBS modified asphalt cohesion in kPa, CdThe calibration factor of the dynamometer is expressed in kPa/0.01mm, RmThe maximum shear deformation reading for SBS modified asphalt is in units of 0.01 mm.
Example 12
The method of the embodiment comprises the following steps:
aligning and matching an upper box 4 and a lower box 2 in an improved strain control type direct shear instrument, inserting a fixed bolt into a corresponding bolt hole 7 to assemble a shear box, and then coating an asphalt separant on the inner wall and the bottom surface of the shear box; the upper box 4 is internally provided with a round hole which is formed by a large-diameter round hole and a small-diameter round hole in a through mode and has a reverse convex-shaped longitudinal section, and the lower box 2 is internally provided with a blind hole which is formed by a large-diameter round hole and a small-diameter round hole and has a convex-shaped longitudinal section; the inner diameters of the large round hole in the upper box 4 and the large round hole in the lower box 2 are both 40mm, the height of the large round hole in the upper box 4 is 15mm, the height from the bottom surface of the large round hole to the scale mark is 10mm, the height of the large round hole in the lower box 2 is 10mm, the inner diameters of the small round hole in the upper box 4 and the small round hole in the lower box 2 are both 20mm, and the heights of the small round hole and the small round hole are both 10 mm; the asphalt separant is prepared from talcum powder and glycerol according to the weight ratio of 1: 2 in a mass ratio;
step two, heating SBS modified asphalt to 160 ℃, slowly pouring the SBS modified asphalt into the shear box coated with the asphalt separant in the step one to the scale mark, ensuring that the heated SBS modified asphalt completely fills the large round hole of the lower box 2 in the shear box, then placing the shear box at 25 ℃ for cooling for 2 hours, and then preserving the heat for 2 hours under the condition of 60 ℃ oven heat preservation;
step three, rotating a hand wheel 8 to drive a pushing seat 1 to push a lower box 2, driving the shear box filled with SBS modified asphalt after heat preservation in the step two to roll along the horizontal direction until steel balls on an upper box 4 contact a dynamometer 5, and then adjusting the reading of a dynamometer 6 on the dynamometer 5 to return to zero; the measuring range of the force measuring dial indicator 6 is 10mm, and the division value is 0.01 mm;
fourthly, pulling out a fixed bolt of the shear box, starting a stopwatch, simultaneously rotating the hand wheel 8 at a constant speed of 10 s/week and observing a pointer of the force measurement dial indicator 6, and when the pointer of the force measurement dial indicator 6 continuously advances along with the rotation of the hand wheel 8, setting the reading of the force measurement dial indicator 6 when the hand wheel 8 rotates for 100 weeks as the maximum shear deformation reading 389.00(0.01mm) of the SBS modified asphalt;
step five, the hand wheel 8 is reversed to the original position, then the shear box is taken down and the SBS modified asphalt is taken out, the shear box is cleaned and then is put back to the original position, and then the shear stress value when the SBS modified asphalt is sheared and damaged, namely the adhesive force tau of the SBS modified asphalt is calculated according to the maximum shear deformation reading of the SBS modified asphalt obtained in the step fourd·Rm1.918kPa/0.01mm × 389.00(0.01mm) ═ 746 kPa/0.746 MPa, where τ is SBS modified asphalt cohesion in kPa, CdThe calibration factor of the dynamometer is expressed in kPa/0.01mm, RmThe maximum shear deformation reading for SBS modified asphalt is in units of 0.01 mm.
The above description is only for the preferred embodiment of the present invention, and is not intended to limit the present invention in any way. Any simple modification, change and equivalent changes of the above embodiments according to the technical essence of the invention are still within the protection scope of the technical solution of the invention.
Claims (7)
1. The asphalt cohesion determination method is characterized by comprising the following steps:
firstly, aligning and matching an upper box (4) and a lower box (2) in an improved strain control type direct shear apparatus to assemble a shear box, and then coating an asphalt separant on the inner wall and the bottom surface of the shear box; the upper box (4) is internally provided with a round hole which is formed by a large-diameter round hole and a small-diameter round hole in a through mode, the longitudinal section of the round hole is in an inverted convex shape, the lower box (2) is internally provided with a blind hole which is formed by a large-diameter round hole and a small-diameter round hole, the longitudinal section of the blind hole is in a convex shape, the inner diameters of the large-diameter round hole in the upper box (4) and the large-diameter round hole in the lower box (2) are the same, and the inner diameters of the small-diameter round hole in the upper box (4) and the small-diameter round hole in the lower box (2) are the same;
step two, heating the asphalt to 140-160 ℃, pouring the asphalt into the shear box coated with the asphalt separant in the step one to the position of the scale mark, then placing the shear box at 20-25 ℃ for cooling for more than 1.5h, and then preserving the heat for 1.5-2.0 h at 60 ℃;
step three, rotating a hand wheel (8) to drive a pushing seat (1) to push a lower box (2), so as to drive the heat-insulated shear box filled with asphalt in the step two to roll along the horizontal direction until steel balls on an upper box (4) contact a dynamometer (5), and then adjusting the reading of a dynamometer dial indicator (6) on the dynamometer (5) to return to zero;
fourthly, pulling out a fixed bolt of the shear box, starting a stopwatch, simultaneously rotating a hand wheel (8) at a constant speed and observing a pointer of the force-measuring dial indicator (6), when the pointer of the force-measuring dial indicator (6) does not advance any more and retreats, the sample is sheared and damaged, the reading of the force-measuring dial indicator (6) is recorded as the maximum shearing deformation reading of the asphalt, and when the pointer of the force-measuring dial indicator (6) continuously advances along with the rotation of the hand wheel (8), the reading of the force-measuring dial indicator (6) when the hand wheel (8) rotates for 100 circles is specified as the maximum shearing deformation reading of the asphalt; the reading of the force measuring dial indicator (6) is accurate to 0.01 mm;
step five, reversing the hand wheel (8) to the original position, taking the shear box down, taking out the asphalt, cleaning the shear box, then returning to the original position, and calculating the shear stress value when the asphalt is sheared and damaged, namely the asphalt cohesion tau is C according to the reading of the maximum asphalt shearing deformation obtained in the step fourd·RmWherein tau is asphalt cohesion and has the unit of kPa, CdThe calibration factor of the dynamometer is expressed in kPa/0.01mm, RmThe maximum shear deformation reading for bitumen is in units of 0.01 mm.
2. The asphalt cohesion determination method according to claim 1, characterized in that in step one, the inner diameters of the large-diameter round hole in the upper box (4) and the large-diameter round hole in the lower box (2) are both 40mm, the height of the large-diameter round hole in the upper box (4) is 15mm, the height of the scale mark in the large-diameter round hole is 10mm, the height of the large-diameter round hole in the lower box (2) is 10mm, and the inner diameters of the small-diameter round hole in the upper box (4) and the small-diameter round hole in the lower box (2) are both 20mm and 10 mm.
3. The method for measuring the cohesion of asphalt according to claim 1, wherein the asphalt in the second step is base asphalt or modified asphalt.
4. The method for determining asphalt cohesion according to claim 1, wherein in the second step, the heat preservation is performed by water bath heat preservation or oven heat preservation.
5. The asphalt cohesion determination method according to claim 1, characterized in that, in the second step, the asphalt is heated and then poured into the shear box coated with the asphalt release agent slowly, and the heated asphalt is ensured to completely fill the large-diameter round hole of the lower box (2) in the shear box.
6. The asphalt cohesion determination method according to claim 1, characterized in that the measuring range of the dynamometer (6) in step three is 10mm, and the division value is 0.01 mm.
7. The asphalt cohesion determination method according to claim 1, characterized in that the rotation speed of the hand wheel (8) in step four is 10 s/week.
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