Mechanical properties of polyethylene fiber reinforced red mud-alkali slag composite

To develop the resource utilization of red mud (RM), RM mixed with slag and silica fume along with addition of polyethylene fibers was used to prepare moderate-to-high strength and high ductile alkali-activated composite, and the macroscopic uniaxial tensile and compressive properties were investigated. The mechanisms of high ductility were explored by meso-scale experiments including three-point bending and single crack tensile tests. Meanwhile, the products of hydration reaction were analyzed through microscopic characterizing. The results show that the tensile strength of the studied material could be up to 2.4 MPa, along with a relatively high tensile strain capacity of 3.5%. The compressive strength could reach around 50 MPa. The larger pseudo strain-hardening P_SH indices obtained by meso-scale tests correspond to the higher tensile strain. Apart from calcium silicate hydrate (C-S-H) or calcium aluminosilicate hydrate (C-A-S-H) gels, the hydration products also contain alkaline aluminosilicate (N-A-S-H) gel.