Complete triaxial stress-strain curves for geopolymer

摘要

Geopolymer is an emerging alternative to Portland cement and is made from fly ash - a waste stream from coal power stations. As a relatively new material, many mechanical properties of geopolymer are still unexplored. In this paper, the stress-strain characteristics of geopolymer under various levels of confining stresses have been studied. Based on triaxial laboratory tests, the relationships between axial-stress and axial-strain, as well as lateral-strain under active lateral confinement, have been developed for high- and low-strength geopolymers (85 MPa and 28 MPa). Tests were performed under a range of confining pressures from 0 to 35 MPa. Based on this work, a constitutive model describing the complete stress-strain behaviour of geopolymer is proposed. The model developed for the constitutive behaviour of geopolymer has many similarities to Portland cement binder; however, differences do exist namely in the form of increased stiffness or reduced ductility in geopolymer compared to Portland cement binder.