Physical-mechanical assessment for soil-cement blocks including rice husk ash

Despite its pozzolan properties, a great percentage of rice husk ash (RHA) is disposed as waste, thus generating adverse environmental impacts. This study was intended to assess compressive strength and absorption in soil-cement block when including RHA as a substitute for Portland cement (PC). This methodology consisted on preparing three mixtures of soil-cement including different RHA percentages as a substitute for PC: M1 (10% PC + 0% RHA), M2 (7.5% PC + 2.5% RHA) and M3 (5% PC + 5% RHA). Results show that compressive strength decreases 12.64% and 26.78% in M2 and M3, respectively. Regarding water absorption, it increases when adding RHA. M2 reported the best results for analyzed properties. However, for both properties, values are present within ranges recommended to be used in construction sector based on Brazilian and Bolivian codes, NBR 10834 and NB 1211003, respectively. Using RHA is viable in order to produce soil-cement blocks as a substitute for PC; however, further tests (e.g. durability, flexural strength, tensile strength, etc.) -in order to determine optimal replacement percentages for quality assurance in produced material- are required. (C) 2021 The Author(s). Published by Elsevier Ltd.

Automated summary

This study evaluated the effects of adding rice husk ash as a substitute for Portland cement in soil-cement blocks, finding that the inclusion of RHA led to decreased compressive strength but increased water absorption. It is concluded that using RHA as a substitute for PC is feasible, although further testing is needed to determine the optimal replacement percentages for quality assurance.