Comparative Study of the Effect of Ashes from Rice Husk, Sugarcane Bagasse and Corn Cob on Mortar Properties

Kenneth Marizane, Arao Manhique and Carvalho Madivate

Background and Objectives: Agro-industrial waste has a potential to be used as partial replacement of cement in mortars. Corn cob is the most abundant agricultural residue in countries where maize meal is the main corn. In this study the comparison of rice husk, sugarcane bagasse, corn cob ashes is carried out as replacement of cement in mortars was investigated. Materials and Methods: The mortars were prepared using ashes partially replacing Portland cement. The ashes were characterized by X-ray diffraction for mineralogical analysis and amorphous content. The mortars performance was determined by flexural and compressive strength. Results: Mineralogical analysis indicate the predominance of silica (quartz) in rice husk ashes, while in other ashes was present not in a dominant position. The mortars produced with rice husks showed the best performance with additions up to 15%, with mechanical properties surpassing those of the reference material, at 28 days of curing age. Corn cob ashes showed a good development of properties at earlier ages, 2 and 7 days with no further improvement in later ages. Sugarcane bagasse ash showed an intermediate performance, between rice husk and corn cob ashes. Conclusion: The study indicates that corn cob ashes did not likely perform as the other two residues. Results indicate for corn cob ashes a filler effect rather than the pozzolanic effect.

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