Micro-surfacing pavement performance evaluation test method based on white-black composite test piece

Abstract

The invention discloses a micro-surfacing pavement performance evaluation test method based on a white-black composite test piece. The micro-surfacing pavement performance evaluation test method comprises the following steps: preparing a test material; manufacturing a micro-surfacing-cement concrete composite test piece; detecting pavement performance data at the micro-surfacing; recording and analyzing the data; evaluating the pavement performance of the micro-surfacing according to the data; according to the invention, the anti-rutting performance is evaluated according to the change of the width deformation rate and the rutting depth rate of the micro-surfacing-cement concrete composite test piece; the micro-surfacing-cement concrete composite test piece is subjected to a soaking thin slurry mixture rutting deformation test, and the change condition of the micro-surfacing during water damage is simulated, so that the water damage resistance of the test piece is measured; meanwhile, the designed accelerated loading type abrasion test can well evaluate the skid resistance and water damage resistance of various asphalt mixtures, so that the method is different from a traditional micro-surfacing detection method, the actual pavement condition can be more accurately simulated through the composite test piece, and the pavement performance of the micro-surfacing can be more accurately evaluated.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of road engineering material performance testing, in particular to a micro-surfacing road performance evaluation test method based on a white plus black composite test piece. BACKGROUND

[0002] Micro-surfacing is a thin layer with high skid resistance and durability, which is formed by special mechanical equipment to mix polymer modified emulsified asphalt, coarse and fine aggregates, fillers, water and additives according to the designed ratio, and is opened to traffic soon. It should be able to meet the requirements of paving different cross-sectional thicknesses, and the mixture with different asphalt contents and different paving thicknesses can resist traffic action and maintain good skid resistance performance within the service life after curing and initial traffic action.

[0003] At present, the road engineering industry in China is developing rapidly, and more and more roads are entering the maintenance period. Micro-surfacing technology, as a preventive maintenance method, mainly plays a role in waterproofing, wear resistance and filling of existing ruts, and can well extend the service life of old roads. Especially in rural roads, the road traffic volume is relatively small, and the main road diseases are ruts and cracks. By adding an asphalt concrete surface layer (black road surface) on the original cement concrete road surface (white road surface), the remaining strength of the old cement road surface is fully utilized to form a "white plus black" composite structure, which can effectively repair these diseases and restore the road use function, and at the same time achieve the goal of improving the aesthetic appearance. However, the increasing traffic volume and heavy-duty vehicles put forward higher requirements for the road performance of micro-surfacing. Accurate evaluation of the road performance of micro-surfacing is of great significance to ensure the long-term use performance and traffic safety of the road. The "white plus black" micro-surfacing is continuously subjected to the rolling and rubbing of the wheels after being formed, and the anti-rutting performance and water damage resistance of the road surface are in dynamic change. To explore the service life of micro-surfacing, it is necessary to detect the overall anti-rutting performance and water damage resistance of the "white plus black" micro-surfacing.

[0004] The test methods for testing the pavement performance of micro-surfacing uniformly prescribed in the prior art mainly include the Technical Specification for Highway Pavement Construction (JTGF40-2004), the Test Regulation for Highway Engineering Asphalt and Asphalt Mixture (JTGE20-2011) and the Technical Guide for Micro-surfacing and Slurry Seal, and related test items and standards. The Technical Specification for Highway Pavement Construction (JTGF40-2004) specifies the definition of micro-surfacing, the technical requirements of raw materials, the design method and technical indexes in detail, which is one of the basic bases for testing the pavement performance of micro-surfacing. The evaluation methods for micro-surfacing in the Test Regulation for Highway Engineering Asphalt and Asphalt Mixture (JTGE20-2011) mainly include the following aspects: the evaluation of anti-rutting ability, the evaluation of compatibility, the evaluation of demulsification time, the evaluation of cohesion and the evaluation of water damage resistance. These evaluation methods provide a scientific basis for the design and construction of micro-surfacing mixture, and ensure that it has good pavement performance and durability in actual application. The Technical Guide for Micro-surfacing and Slurry Seal provides specification and guidance for the development of micro-surfacing in China, which contains the technical requirements for micro-surfacing construction, quality control methods and performance test standards.

[0005] The "white plus black" micro-surfacing composite test piece relates to the composite structure of the cement concrete base layer and the asphalt surface layer, and the performance thereof depends not only on the micro-surfacing mixture itself, but also on the bonding quality between the base layer and the surface layer. However, these specifications lack special detection methods and evaluation indexes for the composite structure, and therefore the detection of the "white plus black" micro-surfacing composite test piece needs to combine special composite structure detection methods and evaluation indexes. By making the "white plus black" composite test piece, the composite structure of micro-surfacing and the original pavement can be better simulated, a more actual test model is provided for the evaluation of the pavement performance of micro-surfacing, and a test method for evaluating the pavement performance of micro-surfacing based on the "white plus black" composite test piece is developed, so as to improve the practicability and reliability of the micro-surfacing technology.

[0006] Based on this, in order to solve the above technical problems, the present application provides an improved test method for evaluating the pavement performance of micro-surfacing based on a white plus black composite test piece. SUMMARY

[0007] In view of the defects in the prior art, the micro-surfacing road performance evaluation test method based on the white plus black composite test piece is provided, the white plus black composite test piece is prepared, the composite structure of the micro-surfacing and the original pavement can be better simulated, a more actual test model is provided for the micro-surfacing road performance evaluation, and the anti-rutting performance is evaluated according to the width deformation rate and the rutting depth rate of the micro-surfacing-cement concrete composite test piece; the water damage resistance of the test piece is determined through the immersion slurry mixture rutting deformation test, and the problem that the existing test method cannot effectively evaluate the interlayer bonding performance, the anti-reflection crack ability and the overall performance of the white plus black composite test piece is solved.

[0008] Specifically, the technical problem to be solved by the present application is that, in view of the defects in the prior art, the micro-surfacing road performance evaluation test method based on the white plus black composite test piece is provided, and the method comprises the following steps: S1: preparing test materials; S2: preparing a micro-surfacing-cement concrete composite test piece; S3: detecting road performance data of the micro-surfacing; S4: recording and analyzing the data; S5: evaluating the road performance of the micro-surfacing according to the data.

[0009] Preferably, the step S2 specifically comprises the following steps: S21: determining the material composition of the micro-surfacing; S22: preparing a test mold; S23: preparing a cement concrete layer in the test mold; S24: preparing a micro-surfacing layer; S25: injecting the micro-surfacing layer prepared in step S24 onto the upper surface of the cement concrete layer.

[0010] S26: cooling to room temperature for standby.

[0011] Preferably, the road performance data in the step S3 comprises anti-rutting performance data and water damage resistance performance data, wherein the anti-rutting performance data is the width deformation rate and the rutting depth rate, and the water damage resistance performance data is the deformation rate of the test piece after the immersion rutting.

[0012] Preferably, the material composition of the micro-surfacing in the step S21 comprises polymer modified emulsified asphalt, coarse and fine aggregates, fillers, water and additives, and the proportion and ratio of the micro-surfacing material composition are determined according to the environment of the project and the performance requirements of the micro-surfacing.

[0013] Preferably, the step S2 specifically comprises the following steps: a) making a test mold; the internal dimensions of the test mold should be 380.0±1.0mm in length and 50.0±1.0mm in width, and a layer of lubricant is applied to the inside of the test mold when in use; b) after mixing and stirring the cement concrete layer components-cement, mineral aggregate and water respectively, pour them into the test mold; c) when the cement is cured to a certain extent, groove the surface of the cement; d) after the cement concrete is completely cured, inject the micro-surfacing sample; evenly spread the prepared micro-surfacing mixture on the surface of the cement concrete layer, use the spreading equipment and rolling equipment to spread and roll, form the micro-surfacing layer, and finally obtain the "white plus black" composite test piece; e) place the "white plus black" composite test piece in an oven for drying and curing, and take out the test piece to cool to room temperature for standby use.

[0014] Preferably, the anti-rutting performance data testing steps are as follows: First, record the sample width and rut depth of the composite test piece before rolling; Then, after demolding the composite test piece, place it in the load wheel load tester, and perform wheel rolling on the composite test piece. After removing the composite test piece, measure the sample width and rut depth after rolling. After the test, calculate the anti-rutting performance data according to the sample width deformation rate and rut depth rate formula in the "Highway Engineering Asphalt and Asphalt Mixture Test Procedures" (JTGE20-2011).

[0015] Preferably, the anti-rutting performance data testing steps are as follows: After demolding the composite test piece, place it in the load wheel load tester, and ensure that the test wheel is in good contact with the surface of the composite test piece. Before starting the load wheel load tester, add a certain amount of water to the surface of the composite test piece to simulate the changes when the micro-surfacing is damaged by water. Measure the width deformation rate and rut depth rate of the composite test piece before and after the test, and finally calculate the rut deformation rate; the rut deformation rate is the deformation rate of the test piece after immersion in water.

[0016] Preferably, after demolding the composite test piece, place it in the load wheel load tester, and perform multiple wheel rolling on the composite test piece. Pour a certain amount of water and stand for one day, and then perform rolling again. Finally, place the test piece in the sun for a certain period of time and perform wheel rolling again to simulate the damage of rain to the micro-surfacing.

[0017] Compared with the prior art, the positive effects of the present application are: (1) the present application can better simulate the composite structure of micro-surfacing and original pavement by making a "white plus black" composite test piece, and provide a more actual test model for the road performance evaluation of micro-surfacing; (2) the present application provides a comprehensive and scientific test method, which can effectively evaluate the road performance of the "white plus black" composite test piece, and can provide a scientific basis for road design and construction; (3) the method for detecting the road performance of micro-surfacing by making a micro-surfacing-cement concrete composite test piece. This method is different from the traditional micro-surfacing detection method, and can more accurately simulate the actual pavement condition through the composite test piece, so as to more accurately evaluate the road performance of micro-surfacing. At the same time, the test pieces of micro-surfacing with different thicknesses can be made for damage comparison to explore the differences in the damage forms of micro-surfacing with different thicknesses. This scientific detection method can reasonably determine the use range and thickness of micro-surfacing, avoid unnecessary waste, save maintenance cost, and has important significance for improving the quality and effect of road maintenance. BRIEF DESCRIPTION OF DRAWINGS

[0018] Figure 1 is a flow chart of the test method of the present application; Figure 2 is a three-dimensional structure schematic diagram of the composite test piece in the present application; Figure 3 is a physical map of the test test piece in the present application; Figure 4 is a physical map of the prepared cement concrete layer in the present application; Figure 5 is a physical map of the present application after simulating road grooving on the cement concrete layer; Figure 6 is a physical map of the prepared composite test piece in the present application; The marks in the drawings are: 1-cement concrete layer, 2-micro-surfacing layer, 3-test test piece. DETAILED DESCRIPTION

[0019] The present application will be further described below in combination with the specific embodiments. Figures 1-6 The present application will be further described below in combination with the specific embodiments.

[0020] The“white plus black”composite test piece generally refers to the structure of adding an asphalt surface layer on an old cement concrete pavement, that is, the combination of rigid base layer and flexible surface layer, and therefore the interlayer bonding performance is crucial to the stability of the overall structure. The Micro-surfacing and Slurry Seal Technical Guidelines mainly targets the slurry mixture, and the material properties are closer to semi-fluid or fluid state. The detection methods mainly target the indicators such as consistency, mixable time and slurry state of the slurry mixture. The above detection methods in the guidelines cannot effectively evaluate the interlayer bonding performance, anti-reflection crack capacity and the like of the overall“white plus black”composite test piece. The Highway Engineering Asphalt and Asphalt Mixture Test Regulations (JTGE20-2011) also lack special evaluation indicators and test methods for composite structures. For example, the test indicators of the micro-surfacing mixture mainly focus on mixable time, cohesion, rut deformation and the like, which cannot directly reflect the integrity of the composite test piece. The test methods in the regulations, such as rut test and Marshall test, mainly target the asphalt mixture of single material. The detection indicators of the micro-surfacing in the Highway Pavement Construction Technical Specifications (JTGF40-2004) mainly include mixable time, cohesion, wet wheel abrasion, load rut deformation and the like, which are mainly used for evaluating the construction performance and initial road performance of the micro-surfacing mixture, and cannot comprehensively reflect the overall performance of the“white plus black”composite test piece.

[0021] The“white plus black”micro-surfacing composite test piece involves the composite structure of the cement concrete base layer and the asphalt surface layer, and the performance thereof depends not only on the micro-surfacing mixture itself, but also on the bonding quality between the base layer and the surface layer. However, these specifications lack special detection methods and evaluation indicators for composite structures, and therefore the detection of the“white plus black”micro-surfacing composite test piece needs to be combined with special composite structure detection methods and evaluation indicators. By making the“white plus black”composite test piece, the composite structure of the micro-surfacing and the original pavement can be better simulated, and a more actual test model for the micro-surfacing road performance evaluation can be provided. A micro-surfacing road performance evaluation test method based on the“white plus black”composite test piece is developed, so as to improve the practicability and reliability of the micro-surfacing technology.

[0022] Based on this, the purpose of the present application is to provide a micro-surfacing road performance evaluation test method based on the“white plus black”composite test piece, which can comprehensively and accurately evaluate the overall road performance of the micro-surfacing, including the anti-rutting performance, water damage resistance and skid resistance and the like, and provide a scientific basis for the material design, construction quality control and road maintenance decision of the micro-surfacing.

[0023] The purpose of the present application can be realized by the following technical scheme: a design method for testing and analyzing the long-term road performance of micro-surfacing based on a“white plus black”composite test piece, the test method flow chart of which is shown in Figure 1 The method comprises the following steps: 1. determining the micro-surfacing material composition: Before the micro-surfacing material composition design research is carried out, the micro-surfacing material composition needs to be determined. Generally, the micro-surfacing material composition includes polymer modified emulsified asphalt, coarse and fine aggregates, fillers, water and additives, etc. The micro-surfacing material composition ratio and proportion need to be determined according to the environment where the project is located and the performance requirements of the micro-surfacing. On the basis of tests and analysis, the performance and service life of the micro-surfacing can be improved through the optimization of the micro-surfacing material composition, so as to improve the overall performance and service life of the pavement.

[0024] 2. Preparation of "white plus black" composite test piece: The specific test steps are as follows: 1) In the initial stage, the test mold required for the test needs to be made, and the internal dimensions should be 380.0 mm in length (error range ± 1.0 mm), 50.0 mm in width (error range ± 1.0 mm). In actual application, the size and shape of the test mold can be adjusted according to specific needs. In order to ensure the smooth progress of the subsequent demolding process, a layer of lubricant should be applied to the inside of the test mold.

[0025] 2) Preparation of cement concrete layer: select standard cement, aggregate, water and other raw materials, mix uniformly according to the designed mixing ratio, pour the mixed cement concrete into the test mold of specific size. When the cement solidifies to a certain extent (solidified to a certain extent that can be grooved without damaging the surrounding cement concrete when grooving), groove the surface to enhance the pavement skid resistance and make it more in line with the actual road; 3) Preparation of micro-surfacing layer: after the cement concrete is completely solidified, inject the micro-surfacing test sample, evenly spread the prepared micro-surfacing mixture on the surface of the cement concrete layer, use special paving and rolling equipment for paving and rolling, form the micro-surfacing layer, and finally obtain the "white plus black" composite test piece, then demold the test mold when it cools to room temperature for standby use.

[0026] 3. Micro-surfacing road performance research test: The specific detection scheme is as follows: The anti-rutting performance is evaluated according to the width deformation rate and rut depth rate of the micro-surfacing-cement concrete composite test piece; The slurry mixture rut deformation test can be used to measure the anti-rutting performance of the slurry mixture under high temperature conditions. The anti-deformation ability of the mixture is mainly evaluated by the rut deformation rate (rut depth rate, width deformation rate). The specific test process is as follows: first, record the width and rut depth of the test sample before rolling. After the test sample is demolded, it is placed in the load wheel load tester, and the wheel rolling is carried out on the test sample. After the test sample is removed, the width and rut depth of the test sample after rolling are measured. After the test is completed, the rut deformation rate is calculated according to the width deformation rate and rut depth rate formula of the test sample in the "Highway Engineering Asphalt and Asphalt Mixture Test Regulations" (JTGE20-2011).

[0027] The micro-surfacing-cement concrete composite specimens were subjected to rutting deformation test of immersion slurry mixture to determine the specimens' resistance to water damage.

[0028] The water damage resistance of micro-surfacing-cement concrete composite specimens can be determined through rutting deformation testing using a water-immersion slurry mixture. The specific test procedure is as follows: After demolding, the specimen is placed in a wheel-load tester, ensuring good contact between the test wheel and the specimen surface. Before starting the wheel-load tester, a certain amount of water is added to the specimen to simulate the changes in micro-surfacing caused by water damage. The rutting deformation rate (width deformation rate and rutting depth rate) is measured before and after the test, and the rutting deformation rate is calculated.

[0029] The accelerated loading abrasion test can well evaluate the anti-skid and anti-rutting performance of asphalt mixtures. In order to study the overall performance of micro-surfacing in a relatively short time, the present invention uses a load wheel tester for testing.

[0030] The steps for the load wheel test are as follows: 1) Set the thickness to The micro-surfacing-cement concrete composite specimen is put into the load wheel tester and the machine is turned on for continuous rolling. After rolling, a shallow layer of rutting marks is produced on the micro-surfacing. After rolling, the rutting marks on the micro-surfacing are only slightly deepened.

[0031] 2) To accelerate the destruction of the microsurfacing, water was poured into the surface after rolling and allowed to stand for a day before rolling again to simulate rain damage. After this second rolling, the rutting depth of the microsurfacing remained minimal, but the surface of the microsurfacing adjacent to the rutting became white, and more noticeable fine cracks appeared. Research indicates that "whitening" refers to "efflorescence," a process generally believed to be caused by materials such as calcium carbonate and silicates, derived from soluble substances in the cement concrete slurry. After immersion, flushing, and dissolution, the soluble substances in the cement concrete slurry of the bridge deck evaporate through the pores due to evaporation or wheel pressure. When the water evaporates, white crystals remain, resulting in "whitening."

[0032] 3) Finally, the specimens were placed outdoors to dry and then rolled over by wheels. The rutting depth of the specimens increased dramatically, and a large amount of aggregate was exposed.

[0033] 4) Set the thickness to The micro-surfacing-cement concrete composite specimen was put into the load wheel tester. After rolling, the specimen was The rutting depth of the specimen deepened slightly. Water was poured into it and it was left to stand for a day before rolling again. After rolling again, the rutting depth at the micro surface did not change much. The fine cracks were smaller than those at the thickness of After sun exposure, the wheel rolling was repeated several times, and the rutting depth increased dramatically.

[0034] The present application studies the long-term road performance of micro-surfacing and obtains the following conclusions: 1) In view of the insufficient detection methods related to micro-surfacing, a micro-surfacing-cement concrete composite test piece is prepared to detect the road performance of micro-surfacing.

[0035] 2) Through the "white plus black" micro-surfacing-cement concrete composite test piece, the whole process of "white plus black" micro-surfacing from paving to failure is simulated more completely, it can be seen that the micro-surfacing will form strength under the load of vehicles after paving, and normal vehicle rolling will not cause serious damage to the micro-surfacing, but under the double action of rain and vehicle load, the soluble substances in the cement concrete floating slurry of "white to black" road will flow out along the gap, forming white crystalline substances. This will reduce the effective content of asphalt, causing the adhesion of micro-surfacing to decrease, and more easily form cracks under the load of vehicles. In addition, the micro-surfacing becomes soft after being exposed to the sun, the self-healing of asphalt cracks decreases, but the asphalt on the surface will be taken away under the action of the wheels, and the exposed mineral aggregate will cause the road skid resistance to deteriorate and the driving noise to increase.

[0036] 3) By preparing test pieces of different thicknesses of micro-surfacing for damage comparison, the differences in the failure forms of micro-surfacing of different thicknesses are explored, it can be seen from the test that the rut depth of thicker micro-surfacing is slightly deeper, but the normal road driving load is relatively uniform. Considering comprehensively, it is suggested that the thicker road surface and the road surface filled with pits and grooves after construction be rolled once with a road roller, which will prolong the service life of micro-surfacing to a certain extent.

[0037] Compared with the prior art, the present application has the following advantages: The present application proposes a method for detecting the road performance of micro-surfacing by preparing a micro-surfacing-cement concrete composite test piece in view of the insufficient detection methods related to micro-surfacing. This method is different from the traditional micro-surfacing detection method, and can more accurately simulate the actual road surface condition through the composite test piece, so as to more accurately evaluate the road performance of micro-surfacing. At the same time, test pieces of different thicknesses of micro-surfacing can be prepared for damage comparison to explore the differences in the failure forms of micro-surfacing of different thicknesses. This scientific detection means can reasonably determine the use range and thickness of micro-surfacing, avoid unnecessary waste, save maintenance cost, and has important significance for improving the quality and effect of road maintenance.

[0038] Embodiment: The present application provides a micro-surfacing road performance evaluation test method based on a "white plus black" composite test piece. Micro-surfacing plays a role in repairing the road skid resistance, filling the rut, and sealing water. The original asphalt mixture road surface of micro-surfacing after paving and forming is continuously subjected to the rolling and rubbing of wheels, and the road skid resistance and water damage resistance are in dynamic change. To explore the service life of micro-surfacing, the road skid resistance and water damage resistance of micro-surfacing need to be detected.

[0039] The specific steps of the present invention are as follows: (1) the steps of micro-surfacing material composition are as follows: 1) Micro-surfacing material selection: Micro-surfacing places extremely high demands on its constituent materials. Stone must be strong, wear-resistant, and clean. Fine aggregate should be manufactured sand or clean stone chips from alkaline stone production. Oversized coarse aggregate must be screened out, and its adhesion to asphalt and polishing properties must meet design specifications. The sand equivalent of synthetic aggregate passing a 4.75mm sieve must be no less than 65%. The emulsified asphalt used must be polymer-modified. Micro-surfacing filler generally uses externally blended cement, with the cement content determined through testing.

[0040] 2) Technical indicators of micro-surfacing modified emulsified asphalt: For micro-surfacing, cationic polymer-modified emulsified asphalt should be used, and the modifier dosage should not be less than 3%.

[0041] 3) Minerals for micro-surfacing: It can be made by mixing coarse and fine aggregates of varying specifications with mineral powder, or by using large-sized boulders and pebbles crushed in multiple stages. Mineral materials can be mixed with fillers such as mineral powder, cement, and slaked lime. The fillers should be dry, loose, and free of lumps.

[0042] 4) Use of additives: The main function of additives is to adjust the construction performance of the slurry mixture, such as mixing time, demulsification speed, and opening time to traffic, and to change the road performance of the mixture to a certain extent.

[0043] 5) Micro-surfacing water requirements: The water used for micro-surfacing must not contain harmful soluble salts, substances that can cause chemical reactions and other pollutants, and drinking water can be used.

[0044] 6) Micro-surfacing mix design: To determine the asphalt-to-aggregate ratio of the micro-surfacing mixture, the aggregate composition must be designed first. The gradation ranges specified in the "Micro-surfacing and Slurry Seal Technical Guidelines" provide basic data for determining the micro-surfacing mix ratio.

[0045] (2) Preparation of micro-surfacing-cement concrete composite specimens. Preparation of micro-surfacing-cement concrete specimens is a key step in the study of micro-surfacing road performance. The specific steps are as follows: a) Make a test mold; b) Mix a certain type of cement, mineral material and water separately, stir them evenly and pour them into a container; c) Waiting for the cement to solidify to a certain extent, grooves are carved on its surface to make it more consistent with the actual road surface; d) After the cement concrete is completely solidified, inject it into the micro-surface specimen; e) After scraping, put into the oven to dry and keep healthy, and take out the test piece and cool to room temperature for standby; (3) Micro-surfacing road performance research test and analysis: Micro-surfacing road performance research needs to be tested and analyzed, including long-term skid resistance, durability, aging performance, fatigue resistance and other aspects of testing and analysis. According to the width deformation rate and rut depth rate of the micro-surfacing-cement concrete composite test piece, the anti-rutting performance is evaluated; the micro-surfacing-cement concrete composite test piece is tested by immersion in water slurry mixture rut deformation test, which simulates the change of micro-surfacing under water damage, so as to determine the water damage resistance of the test piece. Accelerated loading type abrasion test can well evaluate the skid resistance and water damage resistance of various asphalt mixtures, so the load wheel tester is used to evaluate the road performance of micro-surfacing. At the same time, in order to have a more clear and intuitive understanding of the road performance of micro-surfacing, a "white plus black" micro-surfacing-cement concrete composite test piece is made.

[0046] In order to have a more clear and intuitive understanding of the road performance of micro-surfacing, the present application makes a "white plus black" micro-surfacing-cement concrete composite test piece for wheel rolling.

[0047] The road performance of micro-surfacing is greatly affected by the gradation. The "Micro-surfacing and slurry seal guide" gives the suitable range of MS-2 and MS-3 type micro-surfacing mineral aggregate gradation. Considering that MS-3 type gradation has better performance, it is more commonly used in domestic applications. Finally, the average value of the upper and lower limits of MS-3 type gradation is taken as the mineral aggregate gradation for this research. After determining the mineral aggregate gradation, a series of tests are conducted to determine that the content of modified emulsified asphalt is 12% of the mass of the mineral aggregate, the content of cement is 1.5% of the mass of the mineral aggregate, and the content of water is 8% of the mass of the mineral aggregate. Mainly, mixing test, wet wheel abrasion test, and load wheel sand sticking test are conducted for verification.

[0048] After determining the composition of micro-surfacing, the micro-surfacing composite test piece is prepared. Before the test, the test mold is prepared. The size of the mold in the present application is: the internal size is 380.0mm long, 50.0mm wide; the external size is 384.0mm long, 54.0mm wide, and the depth is 40mm, as shown in Figure 3 . Each 1kg of high early strength cement, 1kg of mineral aggregate and 250g of water are mixed and stirred uniformly and then poured into the container. After the cement solidifies, it can be grooved without damaging the surrounding cement concrete when grooving, which enhances the skid resistance and makes it more suitable for actual roads as Figure 4 , 5 . After the cement concrete is completely solidified, the micro-surfacing sample is injected. The thickness of the micro-surfacing is controlled at 7mm and 10mm respectively. After scraping, it is put into a 60 degree oven to dry for more than 16h. The test piece is taken out and cooled to room temperature for standby as Figure 2 ,6 .

[0049] Then the 7mm thickness of micro-surfacing-cement concrete composite test piece is put into the load wheel instrument, 1000 times of load is taken as a test, and the micro-surfacing is constantly opened and rolled. After 1000 times of rolling, the micro-surfacing produces a shallow rut mark. After 10000 times of rolling, the micro-surfacing is only slightly deeper. In order to accelerate the damage of the micro-surfacing, 100g of water is poured after 10000 times of rolling and is left for one day before rolling again to simulate the damage of the micro-surfacing in rainy days. After 5000 times of rolling again, the rut depth of the micro-surfacing changes little, but the surface of the micro-surfacing beside the rut is white and small cracks are obvious. Through reference, the so-called "whitening" refers to "alkali bleeding". People generally believe that these calcium carbonate, silicate and other materials are derived from the soluble substances of the micro-surfacing of the cement concrete pavement. After immersion, washing and dissolution, the soluble substances of the micro-surfacing of the bridge cement concrete pavement flow out from the capillary pores under the evaporation or wheel extrusion, and the white crystalline substances are left after the evaporation of water, thus "whitening" occurs.

[0050] Finally, the test piece is placed outdoors for 3 hours, and 5000 times of wheel rolling is performed, and the rut depth of the test piece increases dramatically, and a large amount of aggregate is exposed. The 10mm thickness of micro-surfacing-cement concrete composite test piece is put into the load wheel instrument, and the same 1000 times of load is taken as a test to start rolling. After 10000 times of rolling, the rut depth of the test piece is slightly deeper than that of the 7mm thick test piece. 100g of water is poured and left for one day before rolling again. After 5000 times of rolling again, the rut depth of the micro-surfacing changes little, and the small cracks are slightly less than those of the 7mm thick test piece. After sun exposure, 5000 times of wheel rolling is performed again, and the rut depth increases dramatically.

[0051] It is worth noting that the above description is merely exemplary to facilitate understanding of the inventive concept according to the present disclosure. In addition, although each operation is described in a specific order, it should be understood that the operation is required to be performed in the specific order shown or in a sequential order, or all the illustrated operations should be performed to achieve the desired results. In certain circumstances, multi-tasking and parallel processing can be advantageous. Similarly, although several specific implementation details are included in the above discussion, these should not be interpreted as limiting the scope of the present disclosure. Certain features described in the context of separate embodiments can also be combined in a single implementation. Conversely, various features described in the context of a single implementation can also be implemented separately or in any suitable sub-combination.

[0052] Although the subject matter has been described in language specific to structural features and / or methodological acts, it is to be understood that the subject matter defined in the appended claims is not necessarily limited to the specific features or acts described above. Rather, the specific features and acts described above are disclosed as example forms of implementing the claims.

[0053] Embodiments of the present disclosure have been described above, as have examples of the disclosure. The description is illustrative and not exhaustive of the disclosure. Many modifications and variations will become apparent to those skilled in the art upon reading the above description. The embodiments described above are meant to be exemplary, and not exhaustive, of the disclosure. Many modifications and variations of the described embodiments will be apparent to those of ordinary skill in the art upon reading this description. The scope of the disclosure is defined by the appended claims, and equivalents thereto.

[0054] In conclusion, only the preferred technical solutions of the present application are embodied, and some changes made by the skilled in the art to some parts of them embody the principles of the present application and should be the technical scope of the present application.

Claims

1. A micro-surfacing road performance evaluation test method based on a white and black composite specimen, characterized in that: The steps include: S1: Prepare experimental materials; S2: Preparation of micro-surfacing-cement concrete composite specimens; S3: Detect road performance data at micro-surface; S4: record and analyze the data; S5: Evaluate the road performance of the micro-surfacing according to the data.

2. The micro-surfacing road performance evaluation test method based on a white-and-black composite specimen according to claim 1, characterized in that: The step S2 specifically includes the following steps: S21: Determine the material composition of the microsurfacing; S22: making a test mold; S23: preparing a cement concrete layer in the test mold; S24: preparing a micro-surfacing layer; S25: injecting the micro-surfacing layer prepared in step S24 into the upper surface of the cement concrete layer; S26: Cool to room temperature for later use.

3. The micro-surfacing road performance evaluation test method based on a white-and-black composite specimen according to claim 2, characterized in that: The road performance data in step S3 includes anti-rutting performance data and anti-water damage performance data, wherein the anti-rutting performance data is the width deformation rate and the rutting depth rate, and the anti-water damage performance data is the deformation rate of the specimen after rutting in water.

4. The micro-surfacing road performance evaluation test method based on a white-and-black composite specimen according to claim 3 is characterized in that: The micro-surfacing material composition in step S21 includes polymer-modified emulsified asphalt, coarse and fine aggregates, fillers, water and additives. The composition ratio and proportion of the micro-surfacing material are determined according to the project environment and the performance requirements of the micro-surfacing.

5. The micro-surfacing road performance evaluation test method based on a white-and-black composite specimen according to claim 3 is characterized in that: The step S2 specifically includes the following steps: a) Make a test mold; the internal dimensions of the test mold should be 380.0±1.0mm in length and 50.0±1.0mm in width. Apply a layer of lubricant on the inside of the test mold when using it; b) Mix the components of the cement concrete layer - cement, mineral aggregate and water - and pour them into the test mold; c) Wait for the cement to solidify to a certain extent and then make grooves on its surface; d) After the cement concrete is completely cured, inject the micro-surfacing sample; evenly spread the prepared micro-surfacing mixture on the surface of the cement concrete layer, and use paving equipment and rolling equipment to spread and compact it to form a micro-surfacing layer, ultimately obtaining a "white and black" composite specimen; e) Place the "white and black" composite specimen in an oven for drying and curing, and take out the specimen to cool to room temperature for use.

6. The micro-surfacing road performance evaluation test method based on a white-and-black composite specimen according to claim 5, characterized in that: The test steps for anti-rutting performance data are as follows: First, the specimen width and rutting depth of the composite specimen before rolling were recorded; The composite specimen is then demolded and placed in a wheel load tester, where wheels are rolled over the composite specimen. The composite specimen is removed and the width and rutting depth of the specimen after rolling are measured. After the test, the anti-rutting performance data is calculated based on the width deformation rate and rutting depth rate formulas in the "Test Procedures for Asphalt and Asphalt Mixtures in Highway Engineering" (JTGE20-2011).

7. The micro-surfacing road performance evaluation test method based on a white-and-black composite specimen according to claim 6, characterized in that: The test steps for water damage resistance performance data are as follows: After demolding the composite specimen, place it in a load wheel tester to ensure good contact between the test wheel and the surface of the composite specimen. Before starting the load wheel tester, add a certain amount of water to the surface of the composite specimen to simulate the changes caused by water damage to the micro-surface. Before and after the test, measure the width deformation rate and rutting depth rate of the composite specimen, and finally calculate the rutting deformation rate; the rutting deformation rate is the deformation rate of the specimen after rutting in water.

8. The micro-surfacing road performance evaluation test method based on a white-and-black composite specimen according to claim 7, characterized in that: After demolding the composite specimen, place it in the load wheel tester. After the composite specimen is rolled over several times by wheels, a certain amount of water is poured into it and it is left to stand for one day before being rolled over again. Finally, the specimen is placed outdoors in the sun for a certain period of time and then rolled over again by wheels to simulate the damage to the micro-surface caused by rainy days.

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