A method for measuring the re-expansion rate of superabsorbent resin in hardened cement slurry

Abstract

The invention provides a measuring method of the re-expansion rate of high-water-absorption resin in hardened cement slurry. Firstly, a container pipe is put onto a glass plate; single particle high-water absorption resin is put into the center of the container pipe; then, stirred cement slurry is cast; the surface of the hardened cement slurry is covered with adhesive tape; only the single particle high-water-absorption resin is exposed. Next, a test sample is soaked into a test solution. The quality difference of the test sample containing the single particle high-water-absorption resin before and after the soaking is measured; the increased volume after the re-expansion is calculated, so that the re-expansion rate of the single particle high-water-absorption resin is obtained. The method is simple and effective, can be used for studying the re-expansion behavior of the single particle high-water-absorption resin in the hardened cement slurry, is favorable for studying the influenceof factors including the cement slurry composition, environment solution property, single particle high-water-absorption resin type and the like on the re-expansion behavior of the single particle high-water-absorption resin, and can also be used for predicting the crack healing effect of the single particle high-water-absorption resin in the cement slurry with the certain composition in a specific environment.

Description

technical field [0001] The invention belongs to the field of cement concrete, in particular to the technical field of improving the self-healing ability of concrete by adopting single-particle superabsorbent resin (SAP), and relates to a method for measuring the reexpansion rate of superabsorbent resin in hardened cement slurry. Background technique [0002] In water environment and high humidity environment (such as 90% humidity), SAP can promote the self-healing of concrete cracks. When SAP is mixed with concrete, it absorbs the mixing water in the concrete and expands; when the concrete hardens, SAP releases the absorbed water and shrinks, thereby leaving initial holes in the concrete, which are equivalent to macroscopic defects. When the external load is high, cracks are generated along the SAP initial pores. In the presence of water, the SAP at the crack can absorb a large amount of water, expand and plug the crack, thereby reducing the water permeability of the cracke...

AI Technical Summary

Problems solved by technology

[0006] The disadvantages of the above-mentioned technologies are: all cracks need to be prefabricated in concrete, but the width and curvature of the cracks are difficult to control; at the same time, the process of prefabricating cracks may cause SAP particle damage, thereby affecting the crack healing ability of SAP

In addition, the neutron diffraction photography test needs to dry the sample for a long time to discharge the moisture inside the concrete; for the concrete with low porosity, the drying period is longer

Processing of tomography test results is time consuming and difficult for large number of repeat tests

In addition, the key to SAP healing cracks is that it can re-expand in cracked concrete. The above-mentioned technical operations are relatively complicated, and can only qualitatively evaluate the effect of SAP on promoting crack healing or verify the existence of healing products, and cannot obtain the dynamics of the single-particle SAP re-expansion process. Therefore, it is impossible to deeply analyze the mechanism of SAP healing cracks

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