Comparative study of corncob ash-based lateritic interlocking and sandcrete hollow blocks

The high cost of conventional walling materials, increase in emission of CO2 due to cement production and improper disposal of corncob lead to persistent bottlenecks in low-cost and sustainable housing delivery, environmental pollution, and agricultural wastage respectively. This study investigates the use of corncob ash (CCA) as cement additive in producing lateritic interlocking blocks (LIB) and compares its physical characteristics and production cost with Sandcrete hollow block (SHB). Portland limestone cement (PLC) was replaced by CCA in varying percentages 5, 10 and 15%. The density, compressive strength and water absorption of the blocks were determined and compared with the Nigerian standard requirements and specifications. The experimental results showed optimal strength at 3% PLC and 10% CCA with a compressive strength of 4.13MPa, water absorption of 6.60% and density of 1869.47Kgm-3 at 28 days curing for LIB. For 450mm × 225mm × 225mm SHB, compressive strength, water absorption and density at 28 days curing were 3.86MPa, 4.69%, and 1849.95Kgm-3 respectively. All the blocks produced satisfied the recommendations of both the Nigerian Building and Road Research Institute and the Nigerian Industrial Standards. The cost per square meter of SHB and LIB was 4.62 USD and 2.35 USD respectively. The experimental results indicated that LIBs have better strength and are cheaper than SHBs. Recycling of CCA as a supplement material seems to be a feasible solution not only to the problem of adopting indigenous waste material in the production of LIB but also to the environmental problem