Performance of rice husk ash blended cement concretes subjected to sulfate environment

This work assessed the performance of rice husk ash (RHA)-based ASTM type I and type V (low tricalcium aluminate (C₃A)) blended cement concrete mixtures subjected to a mixed magnesium–sodium sulfate environment for an immersion period up to 48 months. The concrete mixtures comprised a combination of two Portland cements (type I and type V) and two RHA-blended cements with two water-to-binder ratios of 0·35 and 0·45. In addition to fresh and strength properties, X-ray diffraction, differential scanning calorimetry, mercury intrusion porosimetry and rapid chloride permeability tests were conducted on all concrete mixtures to determine phase composition, pozzolanic activity, porosity and chloride ion resistance. Deterioration of concrete due to mixed sulfate attack and corrosion of reinforcing steel were evaluated by assessing concrete weight loss and measuring corrosion potentials and polarisation resistance at periodic intervals throughout the immersion period of 48 months. Plain (type I/V) cement concretes performed better in terms of deterioration and corrosion resistance than RHA-based type I/V blended cement concrete mixtures in a mixed sulfate environment.