Experimental investigation on water absorption capacity of RHA-added cement concrete

In the recent past, partial replacement of cement by rice husk ash (RHA) in concrete is a prime focus of global researchers for sustainable development in energy and environmental aspects. The present investigation aims at testing the water absorption capacity of the different types and sizes of the RHA-incorporated cement concrete. A design of experiments (DOE) was conducted using the Taguchi method to develop an L₂₇ matrix to assess the individual effects of each variable. From the experimental study, decreasing the RHA size and increasing the RHA loading, higher bulk density, and surface area led to decreasing the water absorption capacity of the RHA-blended cement concrete during curing. Furthermore, 20 wt% replacement of cement by RHA in concrete furnishes the 3-fold decrease of water absorption capacity compared to normal concrete (without RHA). An empirical model was developed to predict the water absorption capacity of the RHA-incorporated cement concrete. The model indicates that RHA loading, silica content, and specific surface area are the key factors influencing the water absorption capacity of the concrete. And the model appears to be able to predict the water absorption capacity of concrete quite accurately with > 95% confidence level.