Evaluation of blended cement mortar, concrete and stabilized earth made from ordinary Portland cement and corn cob ash

Abstract

A study was conducted to determine the effect of using corn cob ash ( cca) (pozzolanic waste by-product of corn cobs) as a cost-reducing additive in blended cement. Various percentages of the blended cement were used to stabilize laterite and clay. The effects of the blended cement in various concrete mixes, mortar and roofing sheets were also analysed. The results show that replacing 50.0 and 20.0% respectively of ordinary Portland cement ( opc) by weight with cca produces stabilized clay and laterite exhibiting greater strength, lower thermal conductivity and lower water absorption than plain cement stabilized earth. The results also indicate that replacing 20.0% of cement with cca in concrete mix and mortar improves water absorption and durability of the specimens while there is no significant difference between the strength of concrete produced with 0.0 and 20.0% cca. Roofing sheets of high quality which comply with BS 690 specifications have been fabricated from clay and laterite stabilized with the blended cement and corn cob fibre ( ccf). The roofing sheets are superior to asbestos roofing sheets which are commercially available in the Nigerian market.