Influence of Nanomodified Waterproofing Agent on the Performance of Rigid Waterproof Concrete in Underground Engineering

Abstract

Waterproof and impermeable problems seriously affect the safe use, normal structure, and working life of concrete projects. The waterproof performance of concrete can be improved by mixing with a proper amount of waterproofing agent; nevertheless, the early strength of concrete will be seriously affected. With the development of complex structures such as larg e spans in soil and water engineering and the increasingly complex engineering environment, people have put forward higher requirements for the working performance, strength, impermeability, durability, and intelligence of cement-based materials required. This article compares the changes in compressive strength, fluidity, and water permeability of mixed concrete by controlling the two variables of waterproofing agent and nanosilica. Combining the results of XRD microstructure analysis, the influence of nanosilica and waterproofing agent on the performance of concrete is explored. Moreover, it is hoped that other excellent properties of concrete can be improved, and a waterproof material with good opacity can be found. The test results show that after adding waterproofing agent alone, the 3 d compressive strength of concrete is decreased by 14.81%, the water permeability is reduced by 71.6%, and the depth of carbonic acid molecules at 28 d is also decreased by 37.3%. On the other hand, compared with concrete using waterproof coating alone, after adding in nanosilica, the 3 d compressive strength is increased by about 30%, and the water immersion height is decreased. The results show that the addition of polymer has a great influence on the compressive strength and carbonic acid resistance of concrete.