Hydrates and Paste Structure of Slag-Fly Ash Based Cementitious Materials

Cascade grinding mode is often applied to prepare Slag-Fly Ash Based cementitious materials with high volume of fly ash and slag and less cement clinker. This process has low water requirement and well fluidity, which is suitable to prepare HPC．When the W/C is 0.36, the 28d compressive strength is 58.93 Mpa, 28d flexural strength is 14.26 Mpa. By X-Ray diffraction analysis (XRD) and Scanning Electron Microscope (SEM) analysis the results show that main materials in grinded sample are well activated by mechanical force and chemical action; more Aft are produced and observed in 3 days hydration products and the great amount of C-S-H gel has continuously generated with the growth of hydration time. By Infrared(IR) analysis, the results show that in the hydration products, the network of Silicon Oxygen Tetrahedron and Aluminum Oxygen Tetrahedra have depolymerized significantly; in the hydration process and various raw materials mutually promoted each other to accelerate the hydration reaction. The hydrates and paste structure of slag-fly ash based cementitious materials were explained．