Superhigh strength of geopolymer with the addition of polyphosphate

Abstract

Geopolymers (GPs) have an important applications in the construction and medical fields owing to their attractive physical and thermal properties. However, the compressive strength of GP is usually less than 80MPa; therefore, it should be further strengthened to improve the mechanical strength and structural properties of end products. This study presents a facile method to enhance the compressive strength of GP by incorporating aluminum dihydrogen triphosphate (ATP) into the GP matrix during the geopolymerization of metakaolin. The microstructure, thermal properties, and compressive properties of the doped GPs (D-GPs) are investigated. The results show that the ATP is transformed to many granules, bonded and surrounded by GP gel, and the unique microstructure increases the compressive strength of D-GP to 160MPa with an optimum 1.0wt% ATP, which is a 108% increase as compared to pure GP. The superhigh compressive strength of ATP-reinforced GP makes them potential alternatives for existing high-strength cement materials.