Hydration and phase formation of blended cementitious systems incorporating chemically transformed rice husk ash

Rice husk ash (RHA) has been used as a supplementary cementing material (SCM). However, because RHA contains a cellular, honeycomb-like morphology, the use of RHA in concrete results in reduced workability and increased water requirements. Reduced workability and increased water requirements can be mitigated by reducing the RHA particles. Smaller RHA particles can be obtained with mechanical grinding. However, mechanical grinding is inefficient because significant energy is required. A recent study assessed a chemical transformation process (“chemical grinding”) and reported that using this process results in reduced RHA particle sizes and an altered cellular morphology. This paper provides results on the early-age hydration and phase formation of the cementitious systems containing chemically transformed RHA (t-RHA). Results indicate that the hydration and phase formation of the t-RHA system is different from the as-received RHA (AR-RHA).