The Impact of Rice Husks Ash on Some Mechanical Features of Reactive Powder Concrete with High Sulfate Content in Fine Aggregate

The sulfate issue in fine aggregate grows with time and it is not easy to gain a fine aggregate with sulfates amount within the specifications of Iraqi standard. Internal sulfate attack is regarded as a significant problem in concrete construction in Iraq and the Middle East countries. One of the modern generations in ultra-high performance concrete is Reactive powder Concrete (RPC) that has been prepared for cemented materials using microstructure improvement methods. RPC has gained attention from both academia and engineering fields with extensive applications. This study presents an experimental research on the impact of Rice Husks Ash (RHA) as replacement percentage of cement upon some mechanical features of RPC with high sulfate content in fine aggregate (Three percentages of SO3 = 0.16, 0.5 and 1.2%). Three percentages of RHA (0, 10 and 15%) as a partial substitution of cement weight have been used in this research. The compressive and the flexural strengths have been adopted to attain the impact of adding RHA. The outcomes have showed that the incorporation of RHA has an important influence on the compressive-strength for both with and without internally sulfate attacking. The result has indicated that using 10% of RHA as a partial cement substitution has increased the effectiveness of RPC by its mechanical features (compressive and flexural-strengths) without internal sulfate attacked