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Showing posts with label Concrete Cube Test. Show all posts
Showing posts with label Concrete Cube Test. Show all posts

Monday, September 17, 2018

Details about concrete compaction methods

Compaction stands for one of the crucial methods of concreting. By compaction, the air voids is dissipated from the concrete.

With the existence of air voids, the honeycomb in concrete is created and the strength of the concrete is reduced significantly. 1 % of air voids decrease the concrete strength roughly 6 %.

Either manual or mechanical process is undertaken for the compaction of concrete. Manual compaction is performed by hand devoid of applying any machines rather it is performed with tamping rods.

In mechanical compaction, the vibrators are used to make compaction.

METHODS OF COMPACTION OF CONCRETE: They are many factors consider for choosing compaction method is undertaken on the basis of several factors like reinforcement quantity and spacing, depth of concrete structure, nature of availability of machines, position of concrete structure, concrete paste consistency , form work difficulty.

Different Methods of compaction are given below :-

HAND COMPACTION METHOD: Hand compaction is performed with the following three methods namely Roding, ramming and tamping.

In Roding method a rod with 2 m length and 16 mm dia is utilized. The edge of the rod is sharp. Density of the concrete is 150 mm to 120 mm.

Compaction process is undertaken all through the concrete area. Compaction should be continued unless it becomes entirely compacted.

Another process is tamping. Under this process, the cross beam with dimension 10 cm x 10 cm is employed to compact the concrete. Compaction and concrete surface level is retained evenly. It is suitable for road pavement flooring concrete and roof concrete works.

Mechanical Compaction: In mechanical compaction process, vibration technology is mainly utilized. Vibration leads to temporary liquefaction and as a result reserved air among aggregates is eliminated instantly. In mechanical compaction different types of vibrators are applied which range from internal or needle vibrators, external vibrators, table vibrators, surface vibrator.

There should adequate compaction for concrete structure otherwise honeycomb (air voids) may occur in concrete and it can reduce the strength of concrete significantly.

To get more details, go through the following link www.learntocivilfield.com


Details about concrete compaction methods

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Published By
Rajib Dey
www.constructioncost.co
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Tuesday, September 11, 2018

Concrete Mix Design for different grades of concrete

Concrete Mix Design is the process for choosing appropriate elements of concrete and finding out their relevant ratios with the purpose of developing concrete with specific minimum strength and stability as inexpensively as possible.

Purpose of mix design

To make sure the most favorable ratios of the ingredients of concrete to satisfy the need of the structure that should be built up. Mix design is used for the following purposes :-

To attain the designed/required adaptability in the plastic phase.

To attain required minimum stability in the hardened phase.

To attain the required stability in the specified environment conditions.

To form concrete as inexpensively as possible.

Designing of concrete mix is dependent on the following factors :-

1. Cost
2. Specification
3. Workability
4. Strength and Durability


Given below, the details of concrete mix design for different concrete grades like M20, M25, M30 and higher grades :-

www.onlinecivilforum.com

Concrete Mix Design for different grades of concrete

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Published By
Rajib Dey
www.constructioncost.co
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