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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. In this chapter proportioning, mixing,
curing, properties, tests and uses of plain concrete is dealt in detail. The other improved versions of
concrete are explained and their special properties and uses are pointed out.

Copper

It is a naturally available metal in the form of ores which contain small amount of iron and sulphur. After removing impurities, it is processed electrolytically to get purest metal. This metal is almost indestructible. Copper scrap can be processed to get original copper. Properties of Copper 1. It is having reddish brown colour. 2. Its  Full Article…

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Ferro-Cement

The term ferro-cement implies the combination of ferrous product with cement. Generally this combination is in the form of steel wires meshes embedded in a portland cement mortar. Wire mesh is usually of 0.8 to 1.00 m diameter steel wires at 5 mm to 50 mm spacing and the cement mortar is of cement sand ratio of 1:2  Full Article…

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Cellular Concrete

It is a light weight concrete produced by introducing large voids in the concrete or mortar. Its density varies from 3 kN/m3 to 8 kN/m3 whereas plain concrete density is 24 kN/m3. It is also known as aerated, foamed or gas concrete. Properties of cellular concrete It has the following properties: 1. It has low weight. 2.  Full Article…

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Fibre-Reinforced Concrete (FRC)

Plain concrete possesses deficiencies like low tensile strength, limited ductility and low resistance to cracking. The cracks develop even before loading. After loading micro cracks widen and propagate, exposing concrete to atmospheric actions. If closely spaced and uniformly dispered fibres are provided while mixing concrete, cracks are arrested and static and dynamic properties are improved. Fibre reinforced concrete can  Full Article…

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Prestressed Concrete (PSC)

Strength of concrete in tension is very low and hence it is ignored in R.C.C. design. Concrete in tension is acting as a cover to steel and helping to keep steel at desired distance. Thus in R.C.C. lot of concrete  is not properly utilized. Prestressing the concrete is one of the method of utilizing entire concrete.  Full Article…

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Reinforced Brick Concrete (RBC)

It is the combination of reinforcement, brick and concrete. It is well known fact that concrete is very weak in tension. Hence in the slabs, lintels and beams the concrete in the portion below the neutral axis do not participate in resisting the load. It acts as a filler material only. Hence to achieve economy the concrete in  Full Article…

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Reinforced Cement Concrete (R.C.C.)

Concrete is good in resisting compression but is very weak in resisting tension. Hence reinforcement is provided in the concrete wherever tensile stress is expected. The best reinforcement is steel, since tensile strength of steel is quite high and the bond between steel and concrete is good. As the elastic modulus of steel is high, for the same  Full Article…

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Uses of Concrete

1. As bed concrete below column footings, wall footings, on wall at supports to beams 2. As sill concrete 3. Over the parapet walls as coping concrete 4. For flagging the area around buildings 5. For pavements 6. For making building blocks. However major use of concrete is as a major ingradient of reinforced and  Full Article…

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Desirable Properties of Concrete

Appropriate quality and quantity of cement, fine aggregate, coarse aggregate and water should be used so that the green concrete has the following properties: (a) Desired workability (b) No seggregation in transporting and placing (c) No bleeding and (d) No harshness. Hardened concrete should have (a) required characteristic strength (b) minimum dimensional changes (c) good durability  Full Article…

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Tests on Concrete

The following are some of the important tests conducted on concrete: 1. Slump test. 2. Compaction factor test. 3. Crushing strength test. Slump Test This test is conducted to determine the workability of concrete. It needs a slump cone for test (Fig. 3.3). Slump cone is a vessel in the shape of a frustum of a  Full Article…

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Properties of Hardened Concrete

Strength The characteristic strength of concrete is defined as the compressive strength of 150 mm size cubes after 28 days of curing below which not more than 5 per cent of the test results are expected to fail. The unit of stress used is N/mm2. IS 456 grades the concrete based on its characteristic strength as shown  Full Article…

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Properties of Green Concrete

Workability This is defined as the ease with which concrete can be compacted fully without seggregating and bleeding. It can also be defined as the amount of internal work required to fully compact the concrete to optimum density. The workability depends upon the quantity of water, grading, shape and the percentage of the aggregates present in  Full Article…

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Properties of Concrete

Concrete has completely different properties when it is the plastic stage and when hardened. Concrete in the plastic stage is also known as green concrete. The properties of green concrete include: 1. Workability 2. Segregation 3. Bleeding 4. Harshness. The properties of hardened concrete are: 1. Strength 2. Resistance to wear 3. Dimensional changes 4. Durability  Full Article…

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Curing of Concrete

Curing may be defined as the process of maintaining satisfactory moisture and temperature conditions for freshly placed concrete for some specified time for proper hardening of concrete. Curing in the early ages of concrete is more important. Curing for 14 days is very important. Better to continue it for 7 to 14 days more. If curing is not  Full Article…

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Preparing and Placing of Concrete

The following steps are involved in the concreting: 1. Batching 2. Mixing 3. Transporting and placing and 4. Compacting. 1. Batching: The measurement of materials for making concrete is known as batching. The following two methods of batching is practiced: (a) Volume batching (b) Weight batching. (a) Volume Batching: In this method cement, sand and concrete  Full Article…

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