CN106680113A - Method for evaluating pavement aging situation by adopting interlayer shear test - Google Patents

Abstract

The invention discloses a method for evaluating the aging condition of pavement by adopting an interlayer shear test. It includes the following steps: core sampling of the pavement on site, collecting pavement core samples of different service years that have not yet produced diseased road sections and road sections with corresponding service years; the core samples of road sections that have not yet produced diseased sections are subjected to interlayer shearing between the upper layer and the middle surface layer. Shear test, according to the data obtained from the test, make the relevant shear performance aging curve; carry out the interlayer shear test between the upper layer and the middle surface layer on the pavement core sample of the diseased road section, and use the obtained data and charts Carry out disease boundary condition processing to define the disease boundary condition of this section of road surface; conduct joint analysis to jointly evaluate the aging condition of the entire road section. The present invention proposes for the first time the method of joint analysis of the disease boundary condition and the aging curve to determine the aging condition of the pavement core sample, and all the analysis results are defined according to the detection data of the interlayer experiment. Compared with other methods, the evidence is stronger applicability.

Description

Method of Evaluating Pavement Aging by Interlayer Shear Test

technical field

The invention belongs to the technical field of construction, and in particular relates to a method for evaluating the aging condition of pavement by using an interlayer shear test.

Background technique

Due to its unique semi-flexible characteristics, asphalt pavement is prone to diseases under aging and special environments. One of the most important types of disease is rutting. Regarding the cause of rutting, the current research believes that this is mainly due to the interaction of factors such as the softening of asphalt materials in high temperature environments and the attenuation of shear resistance between layers.

Interlayer shear resistance is an important road quality index, which characterizes the ability of pavement to resist interlayer shear force. The interlayer shear test is a routine experiment to study the interlayer shear performance of asphalt mixture. This experiment tests the shear strength between layers to characterize the adhesion between different layers of the pavement. It is also used for To characterize the shear strength of the mixture itself. This test has multiple choices in the selection of the research object type. The selection of the research object of the present invention is to evaluate the aging situation of the road surface by detecting the shear performance of the core sample taken back from the road surface, so as to explore the different positions and different service years of the disease. The law of the interlaminar shear properties of the core samples. Although many studies on interlayer shear force have been carried out at home and abroad, and interlayer shear force tests with different sizes and different experimental methods have been carried out, but the interlayer shear test is used to retrieve the core by detecting the road surface. A method to evaluate pavement aging by using such shear properties has not yet been proposed.

Contents of the invention

The purpose of the present invention is to provide a method for evaluating the aging condition of pavement by using an interlayer shear test. The inventive method is not only simple to operate, scientific and effective, but also can obtain the attenuation of the interlayer shear resistance performance through the accurate test of the on-site core sample interlayer shear force, so as to accurately evaluate the pavement aging condition.

To achieve the above object, the present invention adopts technical scheme as follows:

The method for evaluating pavement aging by interlayer shear test includes the following steps:

On-site pavement core sampling, collect pavement core samples of road sections with different service years that have not yet had disease and road sections with corresponding service years;

Carry out the interlayer shear test between the upper layer and the middle surface layer on the core samples of different service years that have not yet produced diseased road sections, and make its relevant shear resistance performance aging curve according to the data obtained by the test; The shear performance aging curve diagram includes interlayer shear strength diagram, maximum strain diagram and shear stress-strain curve diagram; Severe, otherwise the aging is slight;

Carry out an interlayer shear test between the upper layer and the middle layer on the pavement core samples of the diseased road sections with corresponding service years, process the obtained data and charts with disease boundary conditions, and define the disease boundary conditions of this section of road surface; the boundary The conditions are the average interlayer shear strength, average maximum strain, and slope of the shear stress-strain curve of the diseased section of the corresponding service life; the greater the average interlayer shear strength, the smaller the average maximum strain, and the closer the stress-strain curve is to Type S means the aging is milder, otherwise the aging is severe;

Jointly analyze the shear resistance performance aging curves of the above-mentioned road sections with different service years that have not yet had disease and the disease boundary conditions of the diseased road sections with corresponding service years to jointly evaluate the aging of the entire road section.

According to the above-mentioned plan, the road sections with different service years that have not yet produced diseases are road sections on the same road to be tested, and the time span is half a year to one year.

According to the above scheme, the pavement core samples of the diseased road section with corresponding service years are core samples at different positions of the diseased road section, including core samples at non-ruts, ruts and road shoulders.

According to the above scheme, the interlaminar shear test comprises the following steps:

1) Insulate the core sample and the mold at 10°C for at least 5 hours;

2) Set the rising speed of the Marshall stability measuring instrument to 50mm/min, and adjust the level;

3) Take out the insulated mold and put it on the Marshall stability tester platform immediately, take out a core sample at the same time, put it into the mold and fix it;

4) Carry out the Marshall test according to the requirements of the Marshall test specification, and unload the sample immediately after the core sample test is completed, and move the mold back to the incubator to continue the heat preservation;

5) Adjust the machine, record the data, and proceed to the next core sample experiment.

Compared with prior art, the beneficial effect of the present invention is:

The invention starts from the direction of the formation mechanism of the disease based on the interlayer experiment, and evaluates the performance of the pavement from the angle of the anti-shear performance of the interlayer.

For the first time, the method of joint analysis of disease boundary conditions and aging curves is proposed to determine the aging condition of pavement core samples, and all analysis results are defined based on the detection data of interlayer experiments. Compared with other methods, it has stronger application sex.

Compared with other methods, it takes less time, is more efficient, and is more targeted.

Description of drawings

Figure 1: Variation of shear strength between layers of core samples under different service years;

Figure 2: The graph of the maximum strain change between layers of core samples under different service years;

Figure 3: The maximum strain change diagram between core samples under different service years;

Figure 4: The scatter point comparison chart of the average shear strength of the core samples according to the location;

Figure 5: The scatter point comparison diagram of the maximum strain average value of the core samples according to the location;

Figure 6: Comparison of shear stress-strain curves between layers of core samples in the first group;

Figure 7: Comparison of shear stress-strain curves between layers of core samples in the second group;

Figure 8: Comparison of shear stress-strain curves between layers of core samples in the third group;

Figure 9: Comparison of shear stress-strain curves between layers of core samples in group 4;

Figure 10: Comparison of shear stress-strain curves between layers of core samples in the fifth group;

Figure 11: Comparison of shear stress-strain curves between layers of core samples in group 6;

Figure 12: Comparative analysis of shear strength and boundary conditions between layers of core samples with different ages;

Figure 13: Comparative analysis of maximum strain and boundary conditions between layers of core samples with different ages.

detailed description

The following examples further illustrate the technical solutions of the present invention, but are not intended to limit the protection scope of the present invention.

The present invention adopts the method for evaluating pavement aging situation by interlayer shear experiment, and concrete steps are as follows:

On-site pavement core sampling, collect pavement core samples of road sections with different service years that have not yet had disease and road sections with corresponding service years;

Carry out the interlayer shear test between the upper layer and the middle surface layer on the core samples of different service years that have not yet produced diseased road sections, and make its relevant shear resistance performance aging curve according to the data obtained by the test; The shear performance aging curve diagram includes interlayer shear strength diagram, maximum strain diagram and shear stress-strain curve diagram; Severe, otherwise the aging is slight;

Carry out an interlayer shear test between the upper layer and the middle layer on the pavement core samples of the diseased road sections with corresponding service years, process the obtained data and charts with disease boundary conditions, and define the disease boundary conditions of this section of road surface; the boundary The conditions are the average interlayer shear strength, average maximum strain, and slope of the shear stress-strain curve of the diseased section of the corresponding service life; the greater the average interlayer shear strength, the smaller the average maximum strain, and the closer the stress-strain curve is to Type S means the aging is milder, otherwise the aging is severe;

Jointly analyze the shear resistance performance aging curves of the above-mentioned road sections with different service years that have not yet had disease and the disease boundary conditions of the diseased road sections with corresponding service years to jointly evaluate the aging of the entire road section.

Interlaminar shear test process of the present invention is as follows:

1) Insulate the core sample and the mold at 10°C for at least 5 hours;

2) Set the rising speed of the Marshall stability measuring instrument to 50mm/min, and adjust the level;

3) Take out the insulated mold and put it on the Marshall stability tester platform immediately, take out a core sample at the same time, put it into the mold and fix it;

4) Carry out the Marshall test according to the requirements of the Marshall test specification, and unload the sample immediately after the core sample test is completed, and move the mold back to the incubator to continue the heat preservation;

5) Adjust the machine, record the data, and proceed to the next core sample experiment.

On-site pavement core sampling was carried out, and pavement core samples from road sections with different service years that had not yet occurred disease and road sections with the same service life at different locations were retrieved, as shown in Table 1 and Table 2 for details.

Table 1 Classification of core samples according to different years of service

serial number year of milling Year of service Core sample quantity 1 2011 4 8 2 2012 3 8 3 2013 2 8 4 2014 1 8 5 2015 0 8

Table 2 Differentiate the core samples according to the different positions of the disease

Conduct interlayer shear tests on the retrieved core samples of different service years that have not yet produced diseased road sections, and draw the aging curves of their relevant shear resistance performance according to the relevant data obtained from the test, as shown in Figure 1, Figure 2, and Figure 3 shown.

Conduct interlayer shear experiments on the retrieved core samples with different service life and different diseases, process the obtained data and charts with disease boundary conditions, and define the boundary conditions of road surface diseases in this section as shown in Figure 4, Figure 5, Figure 6, Figure 7, Figure 8, Figure 9, Figure 10, Figure 11.

First analyze the aging curve. According to the change diagrams in Figure 1 and Figure 2, it can be seen that the shear strength and maximum strain of the core sample gradually decrease with the increase of service years, that is, they all have a certain degree of attenuation. The relationship between shear strength and maximum strain and the degree of aging of pavement.

According to Figure 3, with the increase of service years, the degree of slope change of the curve gradually decreases, and the flexibility of the surface pavement gradually loses with the passage of service years. At the same time, according to Figure 4, from the scatter plot, we can see that the average shear strength of the core sample at the rut is the lowest, which indicates that the material here has aged; then define the boundary conditions of the disease, and through calculation, in this In the research road section, the average interlayer shear strength of non-rutting, rutting and road shoulders is 2508MPa, 2446MPa and 2423MPa, which is the first boundary condition.

According to Figure 5, since the maximum strain can also be used as a judgment condition, the maximum strain represents the toughness of the material in the shearing process, the greater the maximum strain, the better the material performance, the closer to a semi-rigid material rather than rigid, and the core at the rut The maximum strain of the sample is smaller than that of the core sample at the non-rut and road shoulder, which also proves that the maximum strain of the diseased pavement is also a boundary condition, and boundary condition 2 is obtained.

According to the comparison diagrams of shear stress-strain curves between 1-6 groups of core samples shown in Figures 6, 7, 8, 9, 10, and 11, asphalt pavement is a semi-rigid material with a certain degree of flexibility, which is reflected in the On the stress-strain curve of interlaminar shear, the curve should present an "S" shape or an inverse "S" shape, while the shear stress-strain curve of rigid materials generally presents a straight line. In the six groups of graphs, the curves at the ruts tend to be straight lines, which indicates that the asphalt material has a high degree of aging at the ruts, while the situation at non-ruts and shoulders is slightly better, and it is determined whether the semi-rigid nature is lost. is also one of the boundaries, and boundary condition three is obtained.

Finally, combined with the comparison and analysis of the aging curve and boundary conditions, as shown in Figure 12 and Figure 13, the core samples that have been in service for 4 years are close to the core samples at the diseased site in terms of interlayer shear resistance. Comparing the three aspects of shear strength, maximum stress and slope of the stress-strain curve, compared with the boundary conditions defined in this study, the shear properties of the core samples in service for 4 years are close to those of the core samples in the diseased area, which shows that the core samples in service for 4 years The pavement where the core samples in 2010 is seriously aged and has the risk of rutting, which also shows that its residual life is relatively short. However, the performance of core samples in other service years decreases according to the increase in service years, but there is still a certain residual life. In the case of keeping the status quo unchanged, it can still serve for a long time.

The above is only a preferred embodiment of the present invention, it should be pointed out that for those of ordinary skill in the art, without departing from the creative concept of the present invention, some improvements and changes can also be made, and these all belong to the present invention scope of protection.

Claims (4)

1. using the method for interlayer shear experimental evaluation road surface aging conditions, it is characterised in that comprise the following steps：

To live road surface core boring sampling, the different Years Of Services of collection not yet produce disease section and phase Years Of Service Required disease road The road surface core sample of section；

Different Years Of Services are not yet produced with the interlayer shear-strength test that the core sample in disease section is carried out between upper layer and middle surface layer, Its related anti-shear performance aging curve figure is made according to the data obtained by test；The related anti-shear performance is aging Curve chart includes shearing strength at intersection shearing stress figure, maximum strain figure and shear stress-strain curve figure；Shear strength intensity is got over Low, maximum strain is bigger, load-deformation curve is more precipitous, represent it is aging more serious, otherwise it is then aging slight；

The interlayer shear-strength test between upper layer and middle surface layer is carried out to the road surface core sample in phase Years Of Service Required disease section, will To data and chart carry out disease boundary condition treatment, define the disease boundary condition of the road section surface；The boundary condition It is oblique for the average interlayer shear strength in phase Years Of Service Required disease section, average maximum strain and shear stress-strain curve Rate；Average interlayer shear strength is bigger, and average maximum strain is less, and load-deformation curve is then aging lighter closer to S types It is micro-, on the contrary it is then aging serious；

Above-mentioned different Years Of Services are not yet produced into the related anti-shear performance aging curve figure in disease section and corresponding clothes The disease boundary condition in labour time limit disease section carries out conjoint analysis, the common aging conditions for evaluating whole piece section.

2. as claimed in claim 1 using the method for interlayer shear experimental evaluation road surface aging conditions, it is characterised in that it is described not It is the section on same highway to be measured that disease section is not yet produced with Years Of Service, and temporal span was half a year to 1 year.

3. as claimed in claim 1 using the method for interlayer shear experimental evaluation road surface aging conditions, it is characterised in that the phase Core sample of the road surface core sample in Years Of Service Required disease section for diverse location at disease section, including non-rut, rut and curb The core sample at place.

4. as claimed in claim 1 using the method for interlayer shear experimental evaluation road surface aging conditions, it is characterised in that the layer Between shearing test comprise the following steps：

1) core sample and mould are incubated in the environment of 10 DEG C, temperature retention time is at least 5h；

2) the Marshall stability analyzer rate of climb is set for 50mm/min, and level-off；

3) it is placed on Marshall stability analyzer platform at once after take out the mould of good heat insulation, while a core sample is taken out, Fix in being put into mould；

4) Marshall Test is carried out according to Marshall Test code requirement, and carry out immediately unloading sample after this core sample off-test, And mould is moved back to into couveuse continuation insulation；

5) machine is adjusted, record data carries out the experiment of next core sample.