Effect of raw materials and proportion on mechanical properties of magnesium phosphate cement

Magnesium phosphate cement (MPC) cementitious material is a phosphate cement-based material with strengthformed by a serious of acid-base neutralization reactions among magnesium oxide, phosphate retarder and water,which has a high early strength and a broad application prospect in the field of pavement rehabilitation. Thisreview collects and organizes the latest progress in the field of research on the influencing factors of mechanicalproperties of magnesium phosphate cementitious materials worldwide in recent years, and discusses the possibilitiesof application in airport engineering.The type of phosphate has a great influence on the reaction products, and the strength of the reaction productsof ammonium salt is higher. Borax is the most commonly used retarder, and the retarding effect is related to theratio of boron to magnesium. However, borax retarders have an adverse effect on the strength of MPC. In terms ofthe influence of mineral admixtures on the properties of MPC, fly ash, silica fume and metakaolin, as commonmineral admixtures, have a positive influence on the mechanical properties of MPC, but the mechanism anddegree of the influence of the three materials on the strength of MPC are slightly different;Aggregates can alsoimprove the volume stability and mechanical properties of MPC by forming skeleton structure and slowing downthe exothermic reaction. In fiber reinforced MPC matrix, steel fiber is the most widely used and the bondingperformance between special-shaped steel fiber and MPC matrix is higher than that of straight fiber;basalt fiberhas also been proved to be used to improve the mechanical properties of MPC system.