Synthesis of belite cements at low temperature from silica fume and natural commercial zeolite

The paper herein proposes a new simple method for the synthesis of two reactive belite cements at low temperature (1000 degrees C). Silica fume, as subproduct of metallurgic industry and commercial natural zeolite were utilized as raw materials. The implemented raw materials were utilized with no additional purification process. Belite cements properties were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS) and gas sorption by BET (Brunauer, Emmett, and Teller) techniques. Hydration capacity of belite cements was calculated while the mechanical strength was determined in ordinary Portland cement pastes (PC) and gypsum pastes, respectively, using in each case a 10% partial replacement of the belite cements obtained. Results showed belite cements presented relatively high surface areas, at early ages mechanical strengths similar to those of alite cement and comparable to strengths of belite cements obtained by different synthesis methods. Cements obtained in this work showed good hydraulic reactivity properties.