Device and method for synchronously testing stretching, compression and bend-stretching rebound moduli of pavement material

Abstract

The invention discloses a device and method for synchronously testing stretching, compression and bend-stretching rebound moduli of a pavement material. The method comprises the steps of affixing resistance strain pieces to the upper and lower surfaces in a test piece span, testing the compression strain and stretching strain of a test piece, testing the deflection in a girder span by virtue of a displacement sensor, and substituting the deflection into a formula, so as to obtain bend stretching, stretching and compression modulus test results of the material. By virtue of the method, three moduli of the material can be simultaneously tested through a single test, so that the accuracy and testing efficiency of the modulus test of the pavement material are improved, the laboratory test cost is lowered, and accurate design parameters are provided for the scientific design, considering the difference between the stretching and compression moduli, of durable pavements.

Description

technical field [0001] The invention relates to a technical method for indoor testing of modulus of road materials in the field of road engineering, in particular to a device and method for testing tensile, compressive and bending elastic modulus of semi-rigid base materials and asphalt mixture beams. Background technique [0002] At present, the design method of asphalt pavement in my country adopts the elastic layered system theory with the assumption of isotropy of structural layer materials, and simply adopts the unconfined compressive resilience modulus as the design parameter in the design of pavement structure. However, it has been proved by a large number of experiments that semi-rigid base materials and asphalt mixtures for road use have anisotropic properties with different tensile and compressive moduli, and the compressive moduli are generally much larger than the tensile moduli. In the actual stress of the pavement structural layer, there are generally both tens...

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Problems solved by technology

The compressive modulus of resilience test is mainly divided into the top surface method or the bearing plate method, both of which are tested under unconfined unidirectional compression; the splitting modulus of resilience is an indirect tensile test, and its The stress state is relatively close to the real stress state of the pavement structural layer; while the flexural-tensile modulus test considers that the material of the pavement structural layer is actually in the stress state of the upper part under compression and the lower part under tension, but the modulus calculation theory is based on the mixed The assumption that the tensile and compressive modulus of the material are the same, and the influence of the shear action on the deflection is not considered, resulting in a large error in the calculated flexural and tensile modulus, which cannot accurately reflect the real mechanical properties of the material

In addition, the three moduli can only be obtained by making test pieces of different shapes and sizes and conducting corresponding tests respectively, resulting in the waste of materials, manpower and other resources and large errors in the test results, which in turn leads to modulus test results. It cannot objectively and truly reflect the deformation resistance of materials or structures

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