SYNTHESIS AND CHARACTERIZATION OF HIGH BELITE SULFOALUMINATE CEMENT THROUGH RICH ALUMINA FLY ASH AND DESULFURIZATION GYPSUM

摘要

The objective of this study was the preparation and characterization of high belite sulfoaluminate cement (HBSC) fromindustrial residues. HBSC promises eco-friendly building materials with great mechanical performance at earlier agesthan Ordinary Portland Cement (OPC). Preliminary results show the formation of main phase dicalcium silicate (C_(2)S)and ye’elimite (C_(4)A_(3)$) at 1250~(o)C, as determined by X-ray diffraction (XRD), are promising. The formation of minerals inthe clinker was analyzed by differential scanning calorimetry-thermogravimetry (DSC–TG). Likewise, Scanning electronmicroscope (SEM) and XRD were used to carry out the analysis of the micro-structural and hydration products. The mainHBSC hydration products, Ettringite and amorphous Al(OH)_(3), were formed in the early stages; however, during the laterstages, monosulfate and Str?tlingite were formed. Isothermal conduction calorimetry measurements indicate that hydrationproperties of the cements are comparable to OPC; the total hydration heat after 3 days was 438 J/g. The optimum compressivestrength values of the mortars after 1-,3-,7-, and 28-days were 24.9 MPa, 33.2 MPa, 35.6MPa and 52.8 MPa which can meetthe requirement of special structures.