Category: Concrete

Water is an important ingredient of concrete. As a general guidance, if the water is fit for drinking, it is fit for making concrete. However, some water containing small traces of sugar is not suitable for concrete. Another yardstick adopted is that if the pH is between 6 and 8 the water is considered to be suitable.…

Fine aggregate is sand, which is usually obtained from rivers or lakes. Sometimes beach sand is also used. In places where sand is not available or a large quantity of sand is needed, crushed stone dust is used. The fineness modulus (F.M.) of sand should be around 2 to 3.2. The following limits may be…

As stated above, coarse aggregates are produced by the disintegration and crushing of rock. Coarse aggregates are usually those particles which are retained on an IS 4.75 mm sieve. Stones that are hard and durable such as granite, basalt, quartzite provide good coarse aggregate. Naturally available river gravels and shingle obtained from sea beaches after…

Aggregates may be classified as (i) normal weight aggregates, (ii) light-weight aggregates and (iii) heavy-weight aggregates. Normal weight aggregates can be further classified into natural and artificial aggregates. They are also classified as coarse or fine aggregates depending on the size. Natural and artificial aggregates are as follows:

Aggregates are the major and important constituent of concrete. They form the body of the concrete as it occupies 70–80% of the volume of concrete. Although aggregates were originally considered to be inert material, they have recently been found to be chemically active to some extent. Cement is the only factory-made component, whereas aggregates (both…

Cement concrete is prepared to a plastic consistency by adding water and this hardens on curing. Plastic concrete is called fresh concrete, which is a freshly mixed material that can be moulded into any shape. The concrete formed to the required shape and cured is said to be hardened concrete. The properties of the concrete, in both…

Concrete is an important construction material consisting of ingredients that are inert materials, viz., coarse and fine aggregates and binding materials, viz., cement or lime. Cement concrete is widely used as plain concrete, reinforced concrete, pre-stressed concrete and precast concrete members. Properties of coarse and fine aggregates and the quality of water to make quality…

The concrete used for the casting of various structural components with or without reinforcement is called precast cement concrete. Fresh concrete is placed and compacted in moulds made for different structural units. After setting and curing they are removed from moulds and used.

cThis concrete has less density compared to the conventional concrete. Light-weight concrete may be prepared (i) by omitting the fine aggregate, (ii) by using light-weight concrete or (iii) by aerating concrete. The concrete prepared by omitting the fine aggregate is called no-fine concrete. It has low drying shrinkage. This is used for cast-in-situ external load-bearing walls,…

Here high tensile steel wires are used as reinforcement instead of mild steel bars. High tensile steel wires are stretched initially to the desired level and concrete is placed. After setting and completion of curing, the concrete is put into use. As the steel wires are initially stretched, the concrete so casted is known as…