ABSTRACT
Factors that affect the strength and durability of concrete include quality and quantity of cement used in a mix, grading of aggregates, shape and surface texture of aggregates, Water/cement ratio, curing methods, admixture. A lot of researches were carried out to identify the best curing method for concrete. The aim of this research work is to assess the efficiency of different curing methods for concrete produced using rice husk ash (RHA) and sugarcane bagasse (SBA) ash as partial replacement of ordinary Portland cement. The objectives were achieved by determining the effects of curing methods on specimens, and by studying the micro structure of the specimens subjected to various curing methods. RHA and SBA were sourced locally and chemical test was carried out to check their chemical properties. The RHA and SBA were used to replace the mixing cement at 5% and 20% respectively. The targeted concrete strength value was 30N/mm2 at 28 days, which serves as the control value. 29.6 N/mm2 and 29.0 N/mm2 were obtained for RHA and SBA concrete respectively at 28 days under immersion method, while 29.2 N/mm2 and 19.0 N/mm2 were obtained for RHA and SBA under spraying method and 29.2 N/mm2 and 20.0 N/mm2 were obtained for RHA and SBA under polythene method. These indicated that immersion curing 7 method was the best curing method for both RHA and SBA specimens. The micro structure analysis also indicated that the specimens subjected to immersion curing method possessed less pores of 0.41 �m� with highest pore ratio of 287.49 �m� and less pores of 0.18 with the highest pore ratio of 257.33 �m� for RHA and SBA respectively. This contributed to higher strength of the RHA and SBA concrete specimens. Water immersion curing method is recommended as the best curing method but spraying method may appear to be more advantageous where water immersion method is difficult to achieve.