In road engineering construction, asphalt mixture is a key structural material, and its mechanical properties directly affect the service life and performance of roads. Therefore, it is a necessary means to ensure the quality of road engineering to detect the mechanical properties of asphalt mixture through various tests.
Uniaxial compression test of asphalt mixture (prismatic method)
Purpose and Scope of Application
The uniaxial compression test is used to determine the mechanical properties of the hot mix asphalt mixture at a specific temperature and loading rate, and the test can be used to analyze the compressive strength, compressive deformation and stiffness modulus of the asphalt mixture during the compression to failure. In this test, 40mm×40mm×80mm prism specimens are usually used, and the relevant data are obtained by compression until they are broken.
Instruments & Materials
The main instruments used include universal materials testing machines or presses, displacement measurement equipment such as LVDT displacement meters, data acquisition systems or X-Y recorders, and thermostatic water tanks or environmental incubators. The test temperature and loading rate need to be determined according to specific requirements, and the conventional rate is 50mm/min.
Test procedure
Specimen preparation – The specimen is cut from wheel-rolled asphalt mixture plates and kept warm in a thermostatic sink or airbox until the specified temperature is reached.
Test operation - after the test piece is removed from the insulation equipment, it is immediately placed on the pedestal of the testing machine and loaded until it is destroyed.
Data acquisition – The load and deformation curves during the loading process are recorded by the data acquisition system in order to calculate the maximum load and the corresponding failure deformation.
Result calculation
Through the load-deformation curve, the compressive strength, compressive failure strain and compressive stiffness modulus of the asphalt mixture were calculated, and the data were statistically analyzed, and the test results were finally obtained.
Bending test of asphalt mixture
Purpose and Scope of Application
The flexure test is designed to evaluate the flexural failure characteristics of a hot-mix asphalt mixture at a specific temperature and loading rate. Especially in cold environments, this test is often used to analyze the low-temperature tensile properties of asphalt mixtures.
Instruments & Materials
The instrumentation required for flexure testing is similar to that for uniaxial compression testing, and typically includes universal materials testing machines, LVDT displacement sensors, data acquisition systems, and thermostatic equipment. The test temperature is generally set at 15°C or -10°C in a low temperature environment.
Test procedure
Preparation of the specimen - the specimen is cut into a trabecular by the asphalt mixture plate formed by wheel rolling, and the specifications are 250mm×30mm×35mm.
Loading and data acquisition - the specimen is bent loaded at a specified temperature at a loading rate of 50mm/min, and the load and mid-span deflection curves are recorded.
Data processing and analysis
According to the load-deflection curve, the bending strength, deformation and other relevant parameters of the asphalt mixture are calculated to evaluate its bending properties.
summary
The mechanical properties of asphalt mixtures under different temperature and loading conditions can be systematically analyzed by methods such as uniaxial compression tests and flexure tests. These test methods not only help to evaluate the compressive strength, flexural strength and stiffness modulus of materials, but also provide reliable technical support for road design and construction quality.
