Assessment of Chloride Ion Penetration of Coconut Shell and Rice Husk Ash Modified Concrete

Abstract

This is because the corrosion of embedded steel reinforcements in concrete because of the ingress of chloride ions is one of the most important durability factors in the construction sector. This experiment was used to test the efficacy of Coconut Shell (CSh) as a partial substitute to coarse aggregate and Rice Husk Ash (RHA) as a partial substitute to cement to minimize chloride ion induced corrosion in reinforced concrete. The research was a response to the necessity to find long-term building material and discuss its usefulness in the sustainable construction, by substituting the 1:2:4 mix ratio CSh with RHA by weight at 0%, 5%, 10%, 15% and 20%. Prism samples 100 x 100 x 500 mm of reinforced concrete were placed in a solution of 5.844g/L NaCl to replicate a chloride rich environment and 150 mm cube samples were left to cure under normal laboratory conditions. The ingress of chloride ions was measured using the gravimetric analysis of the weight loss of the steel reinforcement, compressive strengths were measured at 7, 14, and 28 days. The findings indicated that compressive strength reduced progressively with the replacement rates with the 10 per cent mix providing a good compromise of 16.09 MPa at 28 days. The corrosion rates reduced considerably to 18.52 mm/year in the control mix and 6.17 mm/year in 10 percent replacement, which demonstrates the beneficial effect of RHA and CSh on the corrosion resistance of concrete. Nonetheless, corrosion rates were higher in 15-percent and 20-percent levels, meaning that the matrix integrity was reduced with the increase in the replacements