Experimental study of additive modification on cement-based permeable crystalline waterproof material

To investigate the technology of improving the impermeability of cement-based permeable crystalline waterproof material， a scheme of modifying cement-based permeable crystalline waterproof materials with supplementary additives was proposed. The modification patterns and characteristics of cement-based permeable crystalline waterproof material were studied by examining cement particle size， silica fume content and additive dosage. The particle size， physical and mechanical properties and impermeability of cement were evaluated experimentally， and the performance enhancement data of cement-based permeable crystalline waterproof material was obtained. The results indicated that： （1） The residual amount of cement particles directly influenced the performance of cement-based permeable crystalline waterproof materials， and the mechanical properties of cement‑based materials with low chloride ion content exhibited superior mechanical properties at the content of wollastonite content of 5%， and the cement-based materials with low chloride ion content were better when the content of water-reducing admixture of 0.1%. （2） In the single factor test， the maximum coating impermeability ratio reached 167%. （3） The optimum active additive composition in orthogonal test was 0.3% tartaric acid， 4% sodium silicate and 3% calcium formate. The 28 d compressive strength of the material was 30.5 MPa， the flexural strength was 6.2 MPa， and the water absorption was 6.5%. The research results can provide basis and reference for the popularization and application of cement-based waterproof and impermeability repair materials.