Effect of Curing Humidity on the Deformation and Mechanical Properties of Cemented Paste Backfill

The influence of underground humidity on the mechanical performance of cemented paste backfill (CPB) in metal mines is a problem that cannot be ignored. To this end, this paper conducted the curing experiments of CPB samples under different curing humidity (60%, 80% and 95%). Physical properties such as moisture content and dry density as well as mechanical properties such as uniaxial compressive strength, cohesion and internal friction angle of the CPB samples were monitored during fixed curing time (3, 7, 14 and 28 days). TGA/DTG, XRD and SEM were used to analyse the microstructure of CPB samples under different curing humidity at 3 and 28 days, and a BP neural network prediction model of CPB strength was established based on the obtained data. The results show that the curing humidity has a great influence on the physical and mechanical properties of the paste, and the amount of hydration products and the change of pore structure are the main reasons that affect the properties. In order to ensure the safety and economy of the CPB structure, the influence of environmental humidity on the paste should be considered in the filling design.