CONCRETE

1.) Introduction to Concrete

Introduction-to-Concrete

Plain concrete, commonly known as concrete, is an intimate mixture of binding material, fine aggregate, coarse aggregate and water. This can be easily moulded to desired shape and size before it looses plasticity and hardens. Plain concrete is strong in compression but very weak in tension. The tensile property is introduced in concrete by inducting different materials and this attempt has given rise to RCC, RBC, PSC, FRC, cellular concrete and Ferro cement.

2.) Preparing and Placing of Concrete


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Preparing and Placing of Concrete

The following steps are involved in the concreting:

 Batching

↯ Mixing

↯ Transporting and placing and

↯ Compacting


↯ Batching: The measurement of materials for making concrete is known as batching. The following two methods of batching is practiced:

3.) Shrinkage Reducing Concrete Admixture

shrinkage-reducing-concrete-admixture
shrinkage-reducing-concrete-admixture

Shrinkage-reducing concrete admixture promote expansion of the concrete at about the same volume that normal drying shrinkage is contracting it. The net change in length of the hardened concrete is small enough to prevent shrinkage cracks.

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4.) Design OF Lightweight Aggregate Concrete

design-of-lightweight-aggregate-concrete
design-of-lightweight-aggregate-concrete
Mix design methods applying to normal weight concrete are generally difficult to use with light weight aggregate concrete. The lack of accurate value of absorption, specific gravity, and the free moisture content in the aggregate make it difficult to apply the water/cement ratio accurately for mix proportioning.