Measurement method of re-expansion rate of superabsorbent resin in simulated crack

Abstract

The invention provides a measurement method of reflation rate of super absorbent resin in a simulated crack. The method comprises the following steps: putting a container tube on a cover plate, putting single particle super absorbent resin at the center of the container tube and then pouring well mixed cement paste; covering the surface of the hardened cement paste with an adhesive tape and only exposing the position of the single particle super absorbent resin; putting the cover plate on the surface of a specimen, separating the cover plate from the specimen by using a steel needle and injecting small amount of a binder at the periphery for bonding; subsequently, taking out the steel needle to obtain the simulated crack. The reflation rate of the single particle super absorbent resin is obtained by measuring the area of crack filled by the immersed single particle super absorbent resin. The method is simple and effective and can be used for studying the reflation behavior of the highabsorbent resin in the hardened cement paste in the simulated crack; the influence of cement paste composition, environmental solution properties and crack width on the healing crack efficiency of thesingle particle super absorbent resin is favorably studied; in addition, the method also can be used for predicting SAP crack healing effect of the cement paste with certain composition in a specificenvironment.

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 using superabsorbent resin (SAP). 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 cracked concrete. In a high-humidity environment, SAP absorbs moisture in the environment and gives it to concrete, which can promote ...

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 expand again in cracked concrete. The above-mentioned technical operations are relatively complicated, and can only qualitatively evaluate the effect of SAP in promoting crack healing or verify the existence of healing products, and it is impossible to obtain a single particle of superabsorbent resin in cracks. Kinetic information of the re-expansion process, so that the mechanism of SAP healing cracks cannot be deeply analyzed

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