COMPARATIVE STUDY OF CORNCOB ASH-BASED LATERITIC INTERLOCKING AND SANDCRETE HOLLOW BLOCKS

Abstract

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.