CN106644933A - Testing method of interlayer bonding power of asphalt pavement - Google Patents

Abstract

The present invention relates to a kind of test method of asphalt pavement interlayer cohesive force, and it comprises the following steps: prepare test piece: the cement concrete test piece of lower layer is bonded with the bituminous concrete of upper layer through adhesive layer oil; (2) install test piece, Place the specimen to be tested in the lower fixture, slowly lower the indenter, and continue to lower the indenter so that the upper and lower fixtures are tightly attached, and fix the upper and lower fixtures with the specimen respectively; (3) Start the test and turn on the press , adjust the speed, start the pull-out test, the force value and displacement on the display begin to change, when the test piece is pulled apart, the force value reaches the peak value, record. The test method for interlayer cohesion of asphalt pavement can truly simulate the vertical load of asphalt pavement, obtain cohesion cohesion parameters, and facilitate the evaluation of interlayer material adhesion performance.

Description

A test method for interlayer cohesion of asphalt pavement

technical field

The invention relates to a test fixture for measuring interlayer cohesive force, in particular to a test method for interlayer cohesive force of asphalt pavement.

Background technique

The current asphalt pavement design in my country is based on the theory of elastic layered systems. When calculating and analyzing the stress-strain response of the pavement structure, it is assumed that each layer of the asphalt pavement is a continuous elastic body. It is difficult to achieve complete continuity. Under the action of traffic and environmental factors, interlayer damage often occurs due to insufficient interlayer bonding and it is difficult to resist the shear force generated by wheel loads, resulting in various diseases such as shifting, rutting, and wrapping on the road surface. Therefore, improving and strengthening the bonding between asphalt pavements is of great significance for increasing the shear strength of interlayer materials and preventing such diseases.

However, there are no clear regulations on the evaluation method of the bonding performance of asphalt pavement interlayer materials in the current specifications of our country, and there is a lack of corresponding testing methods. The bonding performance of modified asphalt and emulsified asphalt is only determined by the Engra and standard viscosity to evaluate. A large number of research data show that the interlayer of asphalt pavement is mainly affected by compressive stress, tensile stress and shear stress, while tensile stress and shear stress are not conducive to the bonding between layers, and shear stress is the main factor causing interlayer damage One, especially the shear stress at high temperature. Therefore, the bonding performance of interlayer materials can be evaluated by measuring the bonding shear strength at different temperatures. For this reason, the author of this paper uses the multi-functional shear instrument developed by the research group to study the bonding properties of ordinary asphalt, modified asphalt and modified emulsified asphalt, which are commonly used adhesive layer materials, under different temperature and spraying amount conditions. In the test research, the bond shear strength at different temperatures is proposed as the evaluation index of the bond performance of interlayer materials.

At the current stage, there are many interlayer shear strength test methods used in engineering, but there are many shortcomings, which have a great impact on the test results. The main problems are as follows: ① The working environment of the road surface cannot be truly simulated, that is, the obtained data are not The utilization value is mainly manifested in: vertical load is not considered; ② There is no automatic data collection equipment during the test, and the test accuracy is seriously affected by manual measurement and recording; Situational test results have low accuracy and poor operability.

At present, there is no test method for evaluating the adhesion performance of asphalt pavement interlayer materials.

Contents of the invention

The present invention overcomes the deficiencies of the prior art and provides a method for testing the interlayer cohesion of asphalt pavement, which can truly simulate the vertical load of the asphalt pavement, obtain cohesion cohesion parameters, and facilitate the bonding of interlayer materials performance evaluation.

A test method for interlayer cohesion of asphalt pavement, characterized in that: comprising the steps of:

(1) Preparation of test piece: Prepare the cement concrete test piece, put it in the mold, apply the sticky layer oil evenly, wait for the sticky layer oil to reach the surface dry, and use the wheel rolling method to form asphalt concrete with the same size on it The test piece, the test piece is demoulded after curing to obtain a complete test piece with two layers bonded together. After the test piece is cooled, cut the applicable size, mark it, and prepare for the pull-out test;

(2) To install the test piece, first fix the lower fixture of the test device on the base of the press through nut connection, then place the test piece to be tested in the lower fixture, and at the same time fix the upper fixture of the test device on the press through nuts On the indenter, slowly lower the lowering head, adjust the upper fixture to match the test piece, after the adjustment, continue to lower the indenter, so that the upper and lower fixtures are close, and the upper and lower fixtures are respectively clamped and fixed on the test piece. The installation is complete;

(3) Start the test, turn on the press, adjust the speed, start the pulling test, the force value and displacement on the display begin to change, when the test piece is pulled apart, the force value reaches the peak value, record, the peak value at this time is Calculate the maximum destructive force of the pulling strength, and disassemble the test piece after the test is completed.

Moreover, the test device includes a press and a test fixture. The test fixture includes an upper fixture and a lower fixture. The lower fixture is composed of a horizontal bottom plate and three fixed enclosures on its periphery and a movable plate. The upper fixture is composed of a horizontal The top plate and its outer periphery are composed of three fixed enclosures and one movable panel. The movable panels of the lower fixture and the upper fixture are located on the same side corresponding to the upper and lower sides. The movable panels and the fixed enclosures opposite are connected by parallel screws.

Moreover, the center of the horizontal bottom plate of the lower fixture is provided with a screw hole, which is connected to the base at the axis of the working platform of the press by screws.

Moreover, a nut is welded at the center of the horizontal top plate of the upper fixture, and the pull-out force sensor fixed at the lower part of the axis of the press head is connected through the nut.

Advantage of the present invention and beneficial effect are:

1. The test method for the interlayer adhesion of asphalt pavement adopts a special test fixture. During the test, the test specimen is placed between the upper fixture and the lower fixture. The upper fixture and the lower fixture are respectively equipped with adjustable spaces. Through parallel The screw is loose and tight to adapt to the size of the test piece. The advantages are: the fixture can adapt to the size error of the test piece, ensuring that the test piece can be clamped within a reasonable size range; it can effectively simulate the actual interlayer bonding force on site, and provide real reference data for the application; It is easy to use, and only needs a common pressure testing machine for testing, and it has a wide range of applications.

2. In this test method for interlayer cohesion of asphalt pavement, the test fixture can adjust the movable plate through parallel screws to ensure that the test piece is clamped without damaging the test piece. Through this fixture, the original pulling The strength test results are single, the test area is too small and the error is too large, etc., no matter what kind of structure the pull-out force between layers, including between asphalt concrete and asphalt concrete, between asphalt concrete and cement concrete, between cement concrete and cement concrete As long as the test needs, the corresponding test piece can be formed to measure the adhesion between layers of different material structures.

3. In this test method for interlayer cohesion of asphalt pavement, the center of both ends of the upper and lower fixtures of the test fixture are screwed to connect the pressure testing machine. Being on the same axis, the test process is highly automated and the data is accurate and reliable.

4. The test method for interlayer cohesion of asphalt pavement, the test fixture is flexible and adjustable according to the size of the test piece, and realizes the measurement of interlayer cohesion of each structural layer of the pavement, which has high precision, good authenticity and reliability good sex.

5. The test method for interlayer cohesion of asphalt pavement can truly simulate the vertical load of asphalt pavement, obtain cohesion cohesion parameters, and facilitate the evaluation of interlayer material adhesion performance.

Description of drawings

Fig. 1 is the structural representation of the testing device that the present invention adopts;

Fig. 2 is a view along the direction A of Fig. 1 .

Reference signs:

1-press head, 2-pull force sensor, 3-upper fixture, 4-press, 5-lower fixture, 6-base, 7-working platform, 8-motor, 9-base, 10-level Bottom plate, 11-movable plate, 12-parallel screw rod, 13-screw hole, 14-fixed enclosure.

detailed description

The present invention will be further described in detail below through the specific examples, the following examples are only descriptive, not restrictive, and cannot limit the protection scope of the present invention with this.

A test method for interlayer cohesion of asphalt pavement, comprising the steps of:

(2) Preparation of test piece: Prepare a cement concrete specimen with a length × width × height of 30cm × 30cm × 5cm, put it in a mold of 30cm*30cm*10cm, apply the sticky layer oil evenly, and wait for the sticky layer oil to reach After the surface is dry, the asphalt concrete with the size of 30cm*30cm*5cm is formed on it by wheel rolling method, and the specimen is demoulded after curing to obtain a complete specimen with two layers bonded together. After the specimen is cooled, it is cut. After cutting, the size of the test piece is 10cm*10cm*10cm, marked and ready for pull-out test;

(2) To install the test piece, first fix the lower fixture of the test fixture on the base of the press through nut connection, then place the test piece to be tested in the lower fixture, and at the same time fix the upper fixture of the test fixture on the press through nuts On the indenter, slowly lower the lowering head, adjust the upper fixture to match the test piece, after the adjustment, continue to lower the indenter, so that the upper and lower fixtures are close, and the upper and lower fixtures are respectively clamped and fixed on the test piece. The installation is complete;

(3) Start the test, turn on the press, adjust the speed, start the pulling test, the force value and displacement on the display begin to change, when the test piece is pulled apart, the force value reaches the peak value, record, the peak value at this time is Calculate the maximum destructive force of the pulling strength. After the test, disassemble the test piece. When not testing, maintain the fixture, clean it and apply a layer of oil for protection.

As shown in Figure 1 and 2, the test device of the cohesive force between asphalt pavement layers used in the present invention comprises a press and a test fixture, the test fixture comprises an upper fixture 3 and a lower fixture 5, and the lower fixture consists of a horizontal base plate 10 and a test fixture. Three fixed enclosures 14 and one movable panel 11 on its outer periphery are formed, and parallel screw rods 12 are used to connect the movable panel with the fixed enclosures opposite to each other. The upper fixture is composed of a horizontal top plate and three fixed enclosures on its outer periphery and one movable plate, which is the same structure as the lower fixture. The movable plates of the lower fixture and the upper fixture are located on the corresponding same side up and down.

The center position of the horizontal bottom plate of the lower fixture is provided with a screw hole 13, which is connected to the base 6 at the axis of the working platform 7 of the press 4 by screws. A nut is welded at the center of the horizontal top plate of the upper fixture, and the pull-out force sensor 2 fixed at the lower part of the axis of the pressure head 1 of the press is connected through the nut. The pressure head of the press relies on the motor 8 in the base 9 and the screw drive mechanism on both sides to drive up and down.

During the test, the test specimen is placed between the upper fixture and the lower fixture. The upper fixture and the lower fixture are respectively provided with adjustable spaces, and the parallel screw is tightened to adapt to the size of the specimen.

Although the embodiments and accompanying drawings of the present invention are disclosed for illustrative purposes, those skilled in the art will understand that various alternatives, changes and modifications are possible without departing from the spirit and scope of the present invention and the appended claims Therefore, the scope of the present invention is not limited to the contents disclosed in the embodiments and drawings.

Claims (4)

1. a test method for asphalt pavement interlayer cohesive force, is characterized in that: comprise the steps: (1) Preparation of test piece: Prepare the cement concrete test piece, put it in the mold, apply the sticky layer oil evenly, wait for the sticky layer oil to reach the surface dry, and use the wheel rolling method to form asphalt concrete with the same size on it The test piece, the test piece is demoulded after curing to obtain a complete test piece with two layers bonded together. After the test piece is cooled, cut the applicable size, mark it, and prepare for the pull-out test; (2) To install the test piece, first fix the lower fixture of the test device on the base of the press through nut connection, then place the test piece to be tested in the lower fixture, and at the same time fix the upper fixture of the test device on the press through nuts On the indenter, slowly lower the lowering head, adjust the upper fixture to match the test piece, after the adjustment, continue to lower the indenter, so that the upper and lower fixtures are close, and the upper and lower fixtures are respectively clamped and fixed on the test piece. The installation is complete; (3) Start the test, turn on the press, adjust the speed, start the pulling test, the force value and displacement on the display begin to change, when the test piece is pulled apart, the force value reaches the peak value, record, the peak value at this time is Calculate the maximum destructive force of the pulling strength, and disassemble the test piece after the test is completed. 2. The test method of a kind of interlayer cohesion of asphalt pavement according to claim 1, is characterized in that: described test device comprises press and test fixture, and test fixture comprises upper fixture and lower fixture, and described lower The fixture is composed of a horizontal bottom plate and three fixed fences on its periphery and one movable plate. The upper fixture is composed of a horizontal top plate and its three fixed fences on its periphery and one movable plate. On the same side, the movable plate is connected with the opposite fixed enclosure by parallel screws. 3. the method for testing the cohesive force between a kind of asphalt pavement according to claim 2, is characterized in that: the center position of the horizontal bottom plate of described lower fixture is provided with screw hole, is connected on the working platform of press by screw. on the base of the axis. 4. A method for testing the cohesive force between asphalt pavement layers according to claim 2, characterized in that: the center of the horizontal top plate of the upper fixture is welded with a nut, and the lower part of the axis of the pressure head of the press is connected by the nut The fixed pulling force sensor.