Durability of Concrete Containing Black RHA from Rice Mill

Abstract

The objective of this research was to study durability characteristics of Black Rice Husk Ash (BRHA). Those characteristics were drying shrinkage, autogeneous shrinkage, depth of carbonation reaction, and weight loss of specimens cured in hydrochloric (HCI) and sulfuric (H2SO4)acid solutions. In this study, the replacements of BRHA for cement were 20% and 40% by weight of cementitious materials. The ratios of paste volume to the volume of void content in compacted aggregates (γ) were 1.2, 1.4, and 1.6 while the water to binder (Portland cement and BRHA) ratios were 0.6, 0.7 and 0.8, respectively.

The tested results showed that the drying shrinkage and depth of carbonation reaction of BRHA concrete appeared to be higher than those of the normal concrete, For 20% RRHA concrete, the drying shrinkage was increased more than 40%. In addition, the depth of carbonation was directly varied with ratio of (SiO₂ +Al₂ O₃ +Fe₂O₃) to CaO. However, an autogeneous shrinkage and weight loss due to acid solutions of BRHA concrete were less than those of the normal concrete.