Research on the Performance of Geopolymer Cementitious Materials Based on Orthogonal Experiments
The optimal ratio of geopolymer cementitious materials was determined based on orthogonal and optimization experiments using fly ash and slag as raw materials.The mass ratio of fly ash to slag is 1∶2,the amount of alkali activator is 12%,and the modulus of water glass is 1.2.The reaction mechanism of geopolymer is discussed based on microscopic tests.The results show that the geopolymer cementation system contains C-S-H(calcium silicate hydrate),C-A-S-H(calcium aluminosilicate hydrate),N-A-S-H(sodium aluminosilicate hydrate),which interweave to form a dense microstructure.The reaction products of water mud based cementitious materials are mainly Ca(OH)2,ettringite,SiO2,etc.In addition,the structure layer formed by obvious layered superposition of Ca(OH)2,needle shaped ettringite and other substances can be seen in the interface of cement-based cementitious materials,and the cement-based cementitious materials have many pores,leading to the weaker performance of cement-based cementitious materials than geopolymer cementitious materials.
geopolymercementitious materialsorthogonal testmechanical propertiesmechanism of hydrationmicrostructure