Effect of limestone powder on fracture and flexural benaviour of PVA fibre-reinforced sulfoaluminate cement

In this paper, the effect of the partial substitution of cements with limestone powders (LSPs) with different replacement levels and fineness on the fracture and flexural properties of non-oil-coated polyvinyl alcohol (PVA) fibre-reinforced sulfoaluminate cement (SAC) was experimentally investigated. The properties of the matrix, including the pore structure and fracture behaviour, were evaluated by means of mercury intrusion porosimetry and the double-K fracture model, respectively. The fibre–matrix bonding properties were measured and characterised using pull-out tests on fibre bundles and scanning electron microscopy. The test results show that an LSP replacement level of 20% significantly increases the flexural strength of the PVA fibre-reinforced SAC, while no increase in the ductility is found. In comparison, a higher LSP replacement level – that is, 40% – is more efficient in improving the ductility of the composite in terms of the deformation capacity and pseudo strain-hardening effect; however, this replacement level results in a reduction in the flexural strength of the composite. By utilising a finer LSP with a replacement level of 40%, an improvement in both the flexural strength and ductility of the composite is achieved in comparison to that of the reference samples.status: publishe