Mechanical properties of magnesium potassium phosphate cement

Magnesium potassium phosphate cement (MKPC) is a kind of phosphate hydrate formed by super-burning magnesia, soluble phosphate, a retarder and water in a suitable ratio and neutralised by acid-base neutralisation. A new type of environmentally friendly cementitious material, MKPC has received increasing attention in the field of civil engineering, especially in the field of building structural repair and reinforcement engineering. In this paper, the preparation process and compressive strength of MKPC were studied, and the mechanism of the compressive strength of MKPC was revealed. The shear strength characteristics of MKPC and epoxy resin in the interface between glass fibre sheets and concrete were compared. The results showed that when the water-cement ratio was 0.12 and the composite retarder ratio was 8 %, the compressive strength of MKPC increased to a maximum of 81.4 MPa. The formed BO33- covered the surface of KMgPO4·6H2O and hindered the continuation of the reaction, which resulted in a slow increase in the early compressive strength. MKPC can well replace the epoxy resin in the field of reinforced concrete structure and can significantly improve the interface bonding performance between glass fibre sheets and concrete.