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![]() The strength of concrete is designated as the Characteristic compressive strength of 150mm cube at the age of 28 days when tested with the universal testing machine in N/mm 2.Īs grades of concrete vary between 15 to 80 N/mm 2. The hardened concrete should possess following properties Compressive Strength / Concrete grades: The concrete gains 95% of desired compressive strength within 28days by periodic curing. Learn more about causes of Segregation and Bleeding in concrete & methods to minimize Properties of concrete during its hardened stage: A good concrete should possess no to less bleeding. Separation of water from freshly mixed concrete is called Bleeding. Excessive segregation leads to honeycombing and decreasing in the density of concrete and ultimately loss of strength of hardened concrete. A good concrete should show no to less segregation after mixing. Separation of coarse aggregate from the concrete mix is called Segregation of concrete. ![]() We usually perform Slump test to check workability of concrete. The factors which influence workability of concrete:Ĥ. Workability in concrete possess required lubrication for handling concrete without segregation, and it should be placed in position without losing its homogeneity, compacted with minimum effort and shall be finished easily. A good workable concrete should not show any segregation and bleeding after compaction. The workability of freshly mixed concrete determines the ease and homogeneity with which it can be mixed, placed, compacted and finished. Workability is a complex property of concrete. The Fresh concrete should possess following properties Workability of Concrete: Fresh concrete will be plastic so that it can be moulded to any desired shape. The chemical interaction between cement and water binds the aggregate into a solid mass. Properties of concrete during its plastic stage:. Properties of concrete are controlled and influenced by the various factors, out of them mix proportions plays an important role in concrete strength and these proportions control the properties of strength. It is necessary to know about important properties of concrete for every civil engineer to design a structure. So, the steel bars are accommodated in concrete for tension requirements as steel have a similar value of compression and tension. So under tension, this zone will act as a weak link and concrete will fail at a lower force. The glue which holds the whole system is significantly weaker than aggregates.ĭue to the applied pull force, the glue which holds different constituents of concrete together will break. The aggregates will pull away from each other. In technical terminology, the glue is called as an Interfacial Transition Zone. When force is applied to a concrete member, this glue transfers compressive stresses from one aggregate to another. Aggregate plays an important role to carry compressive forces, and remaining mixture (Cement, Sand, Water) acts as glue to join these aggregates. Now to be specific, concrete is made by mixing Cement, Sand, water, and aggregate. Well, concrete is strong in tension, but compressive nature of concrete is ten times stronger than tension.Ĭompression force in concrete = 10 x Tension force of Concrete ![]() Now the question runs in your mind? Why is concrete weak in tension? Thus the concrete is strengthened by steel, and resultant composite mass is called Reinforced Cement Concrete. To compensate low tensile strength in the concrete reinforced bars are inserted. Why is reinforcement inserted in concrete?Ĭoncrete is very strong in compression but weak in tension. Reinforced bars are inserted in the concrete to make a structure strong enough. Why is concrete extensively used in civil engineering construction?Īs there is no material which competes with the concrete concerning its high compression strength, its flexibility to take any form and shape, highly resistant to fire and no corrosion with negligible maintenance cost.Īs we know that, Concrete alone is not used in the construction structure. Concrete has become a universal building material which is extensively used in civil engineering construction. Compressive Strength / Concrete grades:Ĭoncrete is a composite material obtained by mixing Cement, sand, aggregates, and water in suitable proportions. ![]()
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