Structural Performance of Sugarcane Bagasse Ash Laterized Concrete

Abstract

The need to provide cheaper housing and find alternative to ordinary Portland cement in most part of the world has necessitated research in blending and replacing the constituent materials of concrete. Although many studies have been carried out to assess the suitability of blending cement with sugarcane bagasse ash and sand with laterite soil, however, no work have been done on the combine effect of the two materials on the properties of concrete. This research present the findings on strengths, permeability and structural behavior of concrete beams containing sugarcane bagasse ash and laterite soil to blend traditional concrete and produce sugarcane bagasse ash laterised concrete for low cost housing construction purposes. Sugarcane bagasse ash and lateritic soil were used as blenders and mixed with normal concrete ingredients by replacing partially (a) cement with sugarcane bagasse ash and (b) sand with laterite soil in the proportions 0, 5,10,15 and 20 and 0, 5, 10, 15, 20 and 25% by mass respectively. Concrete mix of 1:2:4 (cement: sand: aggregate) with a water-cement ratio of 0.55 was used to determine the effect of material replacement levels on workability and compressive strength of concrete. The same mix but with a constant slump of 30mm±3mm was used to determine effect of combine material replacement levels on concrete properties and behavior of structural beams. Results of the investigation showed that (a) sugarcane bagasse ash and laterite soil reduces workability of concrete, therefore sugarcane bagasse ash laterised concrete required higher water contents to produce a workable concrete (b) the strengths of concrete was observed to decrease with increase in combine material replacement levels of cement and sand (c) replacement of 20% of cement and 25% of sand by sugarcane bagasse ash and laterite soil respectively, SB-LA-20-25C gave a little higher than the design strength of 20MPa at 28 days, thus indicating the possibility of using laterite soil and sugarcane bagasse ash as replacement for sand and cement respectively in concrete and (d) the permeability of hardened sugarcane bagasse ash laterised concrete was observed to improve as the replacement level of cement and sand increases. Structural performance of 12 reinforced beam specimens SB-LAB-00-00ns1.8-00, SB-LAB-15-20ns1.8-01 and 02, SB-LAB-00-00ns1.2-00, SB-LAB-00-00ns1.2-01 and 02, SB-LAB-05-05ys1.2-01, SB-LAB-10-15ys1.2-01, SB-LAB-10-15ys1.2-02, SB-LAB-15-20ys1.2-01 and SB-LAB-15-20ys1.2-02 with a shear span/effective depth ratio of 1.5 for 1.2m beams and 2.0 for 1.8m beams showed that (a) the presence of the sugarcane bagasse ash and laterite soil improves the deflection at ultimate applied load and shows a superior post cracking behaviour in comparison with the control specimen (b) the ultimate cracking load reduces as the material replacement levels increases and the presence of shear reinforcement also increases the ultimate cracking load (c) the mode of failure of a beam is affected by the material replacement levels and the presence of shear reinforcement and finally (d) the ultimate shearing stress reduces as the material replacement levels increases and was also observed that the presence of shear reinforcement increases the shear stress, however, all the beams satisfied the preliminary shear requirement by BS8110-1:1990.