Published by: Harga Besi Beton
Almost all concrete structures are made from steel reinforcements. In almost all situations, it's not possible to find out the steel since it is inside the concrete. Concrete structures created without steel reinforcement won't last long under the forces that will be performing on it over its lifetime.
Composition of Concrete
Under standard conditions, concrete generally includes material for instance sand, crushed stone or gravel, typically known as aggregates, and cement to bind them together. Water is then added to make the mixture plastic enough for form work. For the concrete to get correctly shaped accordingly, it ought to be in a plastic condition during combining. The mixture is then put into forms depending on the shape that is wanted. These forms could be made from wood or steel. Within the forms steel reinforcement might be put depending on strength needed. The cementing material will later harden to provide the concrete the look of a natural stone. The cementing material can be a finely - ground powder manufactured by cement companies. Because of the chemical response with water, the cement later hardens. The mass starts to stiffen in about 45 minutes, and after that is constantly on the harden consistently.
Steel Reinforcement
Concrete beams reinforced with steel can be viewed as a beam if two materials. To know how the two materials will act under stress or strain, it's important to change the composite beam into an equivalent beam of one material. It is very important to realize that the strength of concrete is a lot greater in compression than in tension. It's strong in resisting compressive forces (those that usually crush it) but weak in resisting tensile forces (those that often pull it apart). Hence concrete is the greatest material to use for members that are subjected compressive forces like posts or beams. Whenever a slab or a beam is filled, it deflects, so it features one convex surface and one concave surface. For beams supported on both ends like a floor slab, the top surface will be the concave side while bottom surface would be the convex side. In any beam, the material about the convex side is going to be extended therefore in tension while the material on the concave side is going to be shortened and therefore in compression. Compressive forces is going to be acting on the concave side of the concrete slab while tensile forces will be acting on the convex side. Hence a rectangular beam of concrete will certainly crash from the tensile stresses on the convex. The beam could be greatly strengthened by imbedding steel bars on the convex side. Given that concrete grips the steel powerfully, it will have no sliding of the steel bars with respect to the concrete throughout bending. In practice, the cross-sectional part of the steel bars is generally such that the tensile strength of the concrete on the side is overcome prior to yielding of the steel starts, as well as at greater loads the steel alone requires practically all the tension. Therefore in creating the bending stresses in reinforced-concrete beams, the assumption is that all the strain is used by the steel and all the compression by the concrete.
To produce concrete resist the forces which will act on it, steel is inserted in it for the purpose of resisting the tensile forces. Reinforced concrete is a mix of concrete and steel. The steel is set up so that the two materials behave together like a unit to carry the loads. To shield the steel from harm by fire, the reinforcement in beams and also columns shouldn't be put closer to the exposed surface. Make sure you leave a clearance of about 1.5 inches or around 4 cm. This specs fixes a lower limit for the depth of concrete beneath the reinforcing bars.
