Method for testing shrinkage performance of polypropylene fiber cement stabilized gravel

Abstract

The invention provides a method for testing the shrinkage performance of a polypropylene fiber cement stabilized gravel. The method comprises the following steps: proportioning test pieces, presumingtest premises, maintaining the test pieces, constructing a measuring device and performing drying shrinkage test and temperature shrinkage test. The method provided by the invention has the benefits that through a fiber Bragg grating of the measuring device, a linear relationship between the central wavelength shift of the fiber Bragg grating and the sensing strain of the fiber Bragg grating can be utilized to accurately monitor the dry shrinkage strain and the temperature shrinkage strain of the polypropylene fiber cement stabilized gravel, so that the error of test results is greatly reduced; through placing several thin glass rods with the same cross-sectional diameter between a bottom plate and the test pieces, the test pieces freely expand and contract, so that the situation that thetest pieces can not reach the maximum free expansion and contraction during the test to affect the test results is avoided; through cushioning and placing non-absorbent boards under the test pieces, the support frame deformation caused by the influence of temperature change on the bottom plate can be reduced, so that the stability of the whole test and the scientific accuracy of the test results can be improved.

Description

technical field [0001] The invention relates to the field of road construction, in particular to a method for testing the shrinkage 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 i...

AI Technical Summary

Problems solved by technology

[0004] Polypropylene fibers have a good crack resistance effect on cement concrete and mortar. At present, there are few related studies. The indicators describing the drying shrinkage characteristics of semi-rigid base materials are mainly dry shrinkage strain and drying shrinkage coefficient, which describe the temperature shrinkage of semi-rigid base materials. The indicators of the characteristics are mainly temperature shrinkage strain and temperature shrinkage coefficient. The existing methods for measuring dry shrinkage and temperature shrinkage usually use the dial gauge method and the strain gauge method, but when these two methods measure the temperature shrinkage, The bracket used to place the test piece will also be deformed by the influence of temperature, resulting in inaccurate measurement results, and the free shrinkage of the test piece will be restricted during the test

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