Experimental Investigation on Effect of Fire on Properties of Concrete with the Use of Admixture (original) (raw)
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This multidisciplinary research focuses on the effect of fire on structures due to the Boko Haram insurgency in Maiduguri, Northern Nigeria. It is aimed at giving a further contribution to understand the effect of fire with respect to the local aggregates, quenching methods and proposing an assessment methodology based on a suitable analytical procedure applied to reinforced concrete subjected to sustained fire. Cement, river sand, Bama gravel and water in standard proportion in accordance to BS1881 Part 101 were mixed to produce beams, slabs and cubes of different sizes and cured for 28 days. The samples were burnt in a designed fire simulation furnace using sugarcane bagasse as fuel with varying air velocities for 2 hours. Cooling of samples was carried out using water splashing, CO2 powder fire extinguisher and air cooling methods before the compressive strength tests using a Seidner Compressive Testing Machine and Non-destructive test with Rebound Hammer. The scanning electron m...
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Concrete is a composite construction material consisting basically of a binder, aggregates, water and with or without admixture to modify either or both its physical and chemical properties. The rate at which concrete structures especially buildings are gutted by fire hazards is on the increase and this has adverse effect on the strength, hence, the need to assess the post fire structural strengths of Normal Strength Concrete(NSC). NSC of grade 50 was produced and cast into specimens of sizes 150mm cubes and 100mm x 100mm x 500mm reinforced concrete beams. The concrete cubes and beams were subjected to elevated cyclic thermal loadings after 7, 14 and 28 days of curing, while the rate of heating was maintained at 1 o C/min until the target temperature of (100, 130, 160, 200 and 250) o C where attained and this was maintained for one hour and then allowed to cool at 1 o C/min to room temperature of 32 o C. Unstressed Residual Uniaxial Compressive Test (URUCT and Flexural Stre...
Effect of Admixture on Fire Resistance of Ordinary Portland Cement Concrete
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Ordinary Portland Cement (OPC) Concrete deteriorates considerably when exposed to aggressive environment such as fire or elevated temperatures. The addition of certain materials obtained from agricultural and industrial wastes to OPC concrete could improve its performance in this environment. This paper investigated the effect of Carbide Waste (CW) on the compressive strength of concrete when exposed to fire. This was achieved by partially replacing OPC with 5, 10, 15 and 20 percent (%) of CW to produce 150 x 150 x 150mm concrete cubes. Sample of 100% OPC were also produced and served as the control. The quantities of cement, fine aggregate and coarse aggregate used for the production of concrete specimens were obtained through absolute volume method of mix design. Water/cement (w/c) ratio of 0.65 was adopted for OPC/CW concrete and the control. For the purpose of the research, Ninety (90) concrete cubes were produced for the two specimens. The specimens produced were cured in ordinary water for 28 days after which they were heated in a furnace at varying temperatures of 200, 300, 400, 600, and 800 o C. Specimens were heated for 2 hours at each testing temperature to achieve the thermal steady state after which their compressive strengths were determined. Increase in compressive strength was observed in the control specimen up to 300 o C after which the specimen suffered severe loss with further increase in temperatures up to 800 o C. However, the compressive strength of CW concretes increases with increase in temperature up to 500 o C and then, decreases with further increase in temperatures. 10% replacement of OPC with CW performs satisfactorily better than other replacement level at all temperatures. Replacement of OPC by 10% CW increases concrete resistance to fire by 14% of OPC concrete.