Investigation into The Durability of Laterite Based Interlocking Blocks Blended with Corn Cob Ash in Acid Prone Environment

One of the major aims of a building is that it should satisfy the purpose for which it is built. This can be achieved by the choice of materials that can stand the test of time. The durability of Laterite Interlocking Block (LIB) produced by incorporating Corn Cob Ash CCA was considered in this study. Grain size analysis and Atterberg Limits tests was carried out on the laterite sample. Corn Cob was burnt into ashes to obtain Corn Cob Ash (CCA). CCA was used to replace OPC in five varied percentages of 20, 40, 60, 80 and 100. laterite soil sample with 100% Ordinary Portland Cement (OPC) was used as control sample. LIB of size 225 x115 x 225 mm were produced using laterite, cured and tested for compressive strength before and after immersion in magnesium sulphate - water solution, Density and water absorption were also determined. The % passing sieve No 200 is 20.36%. The coefficient of uniformity (Cu) and coefficient of curvature (Cc) were 5.44 and 0.77. Natural and optimum moisture contents are 12.34 and 9.98% respectively, while maximum dry density is 2.05kg/dm3. 9.40 and 8.57%. Liquid Limit (LL) and Plastic Limit (PL) were 36.00% and 18.88% respectively. Plasticity Index (PI) was 17.12. The soil sample is classified as A – 2 – 6 (0) (AASHTO). The specific gravity is 2.50. CCA was classified as Class - C pozzolan. The 56th day compressive strength at the control and at 20, 40, 60, 80 and 100% CCA replacements before immersion in MgSO4 solution was 7.16, 6.30, 6.35, 5.78, 5.13 and 4.73Nmm-2, respectively; compressive strength after immersion was 3.63, 3.05, 2.86, 2.56, 1.51Nmm-2 respectively and LIB dissolved at 10% CCA replacement. The densities of LIB for control and 2, 4, 6, 8, 10% CCA replacement were 2061.80, 2001.70, 2062.90, 2069.77, 2080.08 and 2093.82Kgm-3, respectively; while water absorptions were 6.58, 5.90, 7.96, 7.20, 7.41,.and 9.69%, respectively. CCA inclusion in LIB production at up to 80% replacement of cement can be used in a non-acidic prone environment. The use of LIB with CCA is not advisable in acid prone environment.