Influence of fine cement sand paste in preparation of cementitious materials

The fine cement replacement in conventional cement plays an important role in the microstructure development. To date, no studies have been done to analyze the mixing of fine cement, sand, and water under partial replacement of conventional cement. Therefore, this paper explores the influence of fine cement sand paste on cementitious materials. In this study, the fine calcium sulfoaluminate cement (CSA) cement was prepared to have an average diameter of 2.4 mu m. Furthermore, its partial replacement at different percentages was investigated and compared to the ordinary Portland cement (OPC) system. For mortar preparation, a new method is proposed in this paper. First of all, the fine cement, sand, and water are mixed to form a paste and then conventional cement is added. Results emphasized that strength, porosity, permeability, and crack widths in the interfacial transition zone (ITZ) are more affected by this technique. It is concluded that partial replacement of 20% fine CSA content results in improved strength by 30%-35% as compared to the OPC system. Moreover, porosity and permeability were also reduced by 60%-70%. Also, the crack widths at the interfacial transition zone (ITZ) were also reduced up to 60%. This new technique for mortar preparation of fine cement can be applied to form a good microstructure network in cementitious composites. (C) 2019 Elsevier Ltd. All rights reserved.