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Concrete is the mixture of cement, aggregate and water. Other added materials at the mixer are referred to as admixtures. It has been the most common building materials for many years now and will still be in decades to come. Concrete is widely used in domestic, rural, commercial, recreational and educational construction. Communities around the world tend on concrete as a safe, strong and simple building material.
Timber is a material gotten from trees and used for construction. It is one of the earliest materials used in construction or building especially in domestic dwelling and furniture. In the recent generation they are used in larger public, commercial and industrial building in the form of timber frames, trussed rafters and glued laminated sections has gotten higher.
Steel is the most important ferrous metal in building construction. It is an alloy of iron and carbon. Pure iron's strength remarkably increases when alloyed with carbon. The tensile strength increases with increasing carbon content but the ductility reduces. Steel having its properties because of the presence of carbon alone is called "Plain carbon steel". Its widespread application for structural uses is on account of the following properties:
Because the cement requires time to fully hydrate before it acquires strength and hardness, concrete must be cured once it has been placed and achieved initial setting. Curing is the process of keeping concrete under a specific environmental condition until hydration is relatively complete. Good curing is typically considered to provide a moist environment and control temperature. A moist environment promotes hydration, since increased hydration lowers permeability and increases strength resulting in a higher quality material. Allowing the concrete surface to dry out excessively can result in tensile stresses, which the still-hydrating interior cannot withstand, causing the concrete to crack.
Ability to retain stormwater.Paved surfaces tend to be impervious and can block natural water infiltration into the soil. This creates an imbalance in the natural ecosystem and leads to problems such as erosion, flash floods, water table depletion, and pollution. Pervious concrete is a special type of structural concrete with a sponge-like network of voids that water passes through readily. When used for driveways, sidewalks, parking lots, and other pavements, pervious concrete can help to retain stormwater runoff and replenish local water supplies.