Experimental Study on the Properties of Phosphate-Based Materials for Rapid Repair of Concrete Cracks

This article studies rapid repair materials by mainly carrying out macro- and micro-performance impact tests. The static volumetric method was used to conduct pore volume-aperture analysis and prove the impact of the durability and repair performance of materials. The results show that 1) material impermeability can be effectively improved by increasing the ratio of active ingredients A:B and reducing the water-to-binder ratio. Adding an appropriate amount of fine aggregate can enable one to adjust the microstructure of the repair material, improve the compactness of the material, and effectively improve the impermeability. 2) An increase in the proportion of active ingredient A, water-binder ratio, sand-cement ratio and fly ash content will reduce the self-shrinkage of the specimen; with increasing NS and silica fume content, shrinkage increases. 3) Through analysis of pore size and pore volume, the total pore volume of the repair material is found to be reduced by 16.0% compared with cement mortar. Within a pore diameter range of 2.00–10.00 nm, the volume of the repair material increases by 78.9% compared to that for cement mortar. The total volume of the mesopores (2–50 nm) in the repair material accounts for 87.7% of the total volume, and the total volume of the mesopores in the cement mortar accounts for 81.23% of the total volume, which further illustrates the excellent macroscopic properties of the repair material.