Method for testing fracture property of polypropylene fiber cement stabilized gravel

Abstract

The invention provides a method for testing the fracture property of a polypropylene fiber cement stabilized gravel. The method comprises the following steps: proportioning test pieces, measuring a fracture leading edge strain field of each of the test pieces, fracture-cutting, performing complementary cutting, sticking strain gauges, acquiring data through a strain acquisition instrument, measuring the mid-span deflection delta of each of the beam test pieces, performing data acquisition, measuring the load of each of the cement stabilized gravel test pieces and calculating the fracture toughness. The method provided by the invention has the benefits that by adopting the middle beam test pieces as test samples, the discreteness existing in test results can be reduced; the rigidity of a test machine can be ensured during the rigid component test between upper and lower pressure plates of the test machine, and the test machine is prevented from releasing the elastic deformation energy accumulated in a test machine body to the test pieces when the test pieces are fractured, so that after the load reaches a peak value, the corresponding test piece is broken immediately, and a full fracture curve cannot be determined; the test results are high in accuracy and reliability; the test is performed through a three-point bending method, so that the production requirements of the test forthe test machine and the test pieces can be reduced; external influence factors are small.

Description

technical field [0001] The invention relates to the field of road construction, in particular to a method for testing the fracture performance of polypropylene fiber cement stabilized gravel. Background technique [0002] Cement-stabilized crushed stone uses graded crushed stone as aggregate, uses a certain amount of cementitious material and sufficient mortar volume to fill the gaps in the aggregate, and paves and compacts according to the principle of embedded extrusion, and its compactness is close to the density. The strength mainly depends on the principle of interlocking and locking between crushed stones. At the same time, there is enough mortar volume to fill the gaps in the aggregate. Its initial strength is high, and the strength increases with age and quickly forms a board, so it has a high The strength, impermeability and frost resistance are good. After the cement stabilized gravel survives, it will not be muddy in the rain, and the surface is solid. It is an id...

AI Technical Summary

Problems solved by technology

[0003] The fracture toughness of concrete is an important index to describe the mechanical properties of concrete. It is an important basis for fracture analysis of concrete materials and reflects the ability of concrete to resist crack expansion. Due to the size effect of the fracture toughness of brittle materials in the test process, the test results of small beam specimens for semi-rigid materials have great dispersion. Therefore, as an attempt to fracture test of semi-rigid materials, There are still deficiencies. At the same time, the best method for measuring the fracture parameters of cement-stabilized gravel is the uniaxial direct tension method. The rigidity, the height of the upper and lower fixtures are centered, and the size of the specimen must be very accurate. Machines with slightly poorer stiffness often cannot measure the descending section of the load-displacement curve, so the fracture energy cannot be calculated, and the centering of the upper and lower fixtures is not good. Or the inaccurate size of the test piece will lead to uneven stress distribution on the tension section of the direct tension test piece, which will seriously affect the accuracy and reliability of the test results

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