The Optimal Dose of the Super Plasticizer (B-V-F) With the Optimal Replacement Ratio of the Rice Husk Ash (RHA) and With Ordinary Portland cement

This study aims to an optimal dose of the superplasticizer (B-V-F) with the optimal replacement ratio of the Rice Husk Ash (RHA) and with ordinary Portland cement (OPC) and compares their results. This study generated RHA by burning rice husk in an appropriate iron container for about 24 hours. To improve pozzolanic activity, RHA was ground in a flour mill. The chemical composition and physical properties of RHA were studied. The experimental program consists of seven groups of concrete mixes with different doses of superplasticizer and replacement percentages of RHA. The first group mix contained four mixtures of OPC with different RHA weight replacements (0, 10%, 15%, and 20%). The second group contains six mixtures with a constant slump (15±3) cm and a water-cement ratio (0.51). The compressive strength of these mixtures was studded and compared with a control mixture (PURE OPC). The sixth group A.1, contains six mixtures with optimal RHA replacement (10%) of OPC with a constant slump of 23 cm, and different plasticizing doses were applied. The result shows that the optimum replacement of RHA was 10% which increased concrete compressive strength by about 32%. The optimal dose of superplasticizer with optimal RHA replacement (10%) was 15 L/m3 which increased compressive strength by about 76%