Carbonation Resistance of Rice Husk Ash Concrete: Interplay Between Replacement Level, Transport Properties, and Carbonation DepthPages 399-408
Binyamien I. Rasoul Abstract:
A systematic parametric experimental investigation was conducted to evaluate the influence of rice husk ash (RHA) incorporation on the durability performance of concrete composites. Six RHA replacement levels, namely 5%, 10%, 15%, 20%, 25%, and 30%, were considered to assess the effects of increasing RHA content on key durability-related properties. Particular emphasis was placed on water permeability and carbonation resistance, which are critical indicators governing the long-term durability and service performance of cement-based composites. The experimental results demonstrated that the incorporation of RHA considerably enhanced the resistance of concrete to water penetration and carbonation. With increasing RHA replacement, the depth of water penetration and carbonation depth progressively decreased. These reductions, together with SEM observations of a denser cementitious matrix, are consistent with refinement of the transport network and reduced pore connectivity. Because pore-size distribution and pore connectivity were not directly quantified, pore refinement is interpreted as a plausible mechanism inferred from the combined permeability, carbonation, and microstructural evidence. These improvements may be attributed to the highly reactive silica present in RHA, which promotes pozzolanic reactions and the formation of additional cementitious hydration products, together with the physical filler effect of the fine RHA particles. Overall, the findings indicate that appropriately proportioned RHA can serve as an effective supplementary cementitious material for improving the durability and long-term performance of concrete composites.
Keywords:
Rice husk ash,
Concrete composites,
Durability,
Carbonation resistance,
Water permeability,
Carbonation depth
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