Friday, August 19, 2016
Brief overview of Reinforced Concrete Materials
Concrete is a artificial product formed by solidifying the mixture of cement, sand, gravel and water in prearranged ratios. Once these compounds are blended, a plastic mass is developed that can be poured in appropriate moulds known as forms and placed standing into rigid solid mass. The chemical reaction of cement and water, in the alloy, is comparatively sluggish and needs sufficient time and perfect temperature for it completion. This time is also called ‘setting time’ and it is segregated into three separate stages. The first stage is labeled as time of initial set that tooks 30 to 60 minutes to be completed. Throughout this stage, the mixed concrete reduces its plasticity and forms apparent resistance to flow. The second stage is called final set and it takes 5 to 6 hours once the mixing process is completed. Throughout this stage, concrete becomes comparatively soft solid devoid of surface rigidity. The third stage contains progressive hardening and the strength is increased significantly. The method is very fast in the primary phase, till around one month once the mixing is completed. In this period, the concrete achieves the maximum capacity for hardness and strength.
Based on the quality and ratios of the compounds utilized in the mix, the properties of concrete differ. Concrete contains sufficient strength in compression but fewer strength in tension. Because of this, concrete becomes feeble in bending, shear and torsion. Therefore, application of plain concrete is restricted where strong compressive strength and weight are mostly required as well as tensile stresses are either completely missing or considerably low. So, in order to apply cement concrete for general structures like beams, slabs, retaining structures etc. steel bars are arranged at tensile zones of the structure which are concreted later on. The steel bars also called steel reinforcement, is implanted in the concrete and acquire the tensile stresses. The produced concrete is called as reinforced cement concrete generally shortened as RCC.