Experimental Study of the Behavior of Cemented Paste Backfill under High Isotropic Compression

Deep and high-stress mining relies on backfill to support exposed host rock surfaces, but the backfill response to isotopic compression is virtually unknown. This paper studied the properties and behavior of a cemented paste backfill (CPB) for different cement contents (CCs) and specimen curing times (CTs), for isotropic stresses up to 6.5 MPa. The isotropic compressive behavior was characterized by an initial linear elastic preyield response quantified by the bulk modulus and a linear inelastic postyield response at high stress. The results showed that the postyield compression line loci depend on cement content and curing time of CPB, and fitting functions were determined to predict this evolving behavior based on cement content and specimen cure time. The results could form the basis for developing and calibrating the isotropic compression hardening laws for future constitutive models.