Most vital part of the construction industry is concrete. The mix is very important. We have to ensure the following
Chips should be cubical (i.e.) to have more than 5/6 sided, so that it can take load on all sides. It should not be flat. It wouldn’t take a load on the flat surface and it is susceptible for easy breakage, so that the concrete strength will fall rapidly.
River sand, coarse is preferable, and no clay should exist in it. It is idle to wash the sand before it mixing of concrete.
It is mostly advised not to add dust in the mix which will dilute the strength of the concrete
Only soft water is to be added. The water PPM should not exceed 100 PPM. The Coimbatore Zone all ground water is average 300 PPM to 3000 PPM. It is to be treated, softened, tested and then only it is added to mix. Proper quantity of water will increase the strength. If more water is added, the mix will be easily flow able but it will reduce the strength of concrete.
So the Water in the mix should come out to loosen the mix, when Vibrator is properly done with needle and betake vibrator it will be only water mix and no loose water will be seen in the mix.
Before pouring concrete the cover block should be checked whether it is fixed below the still Network. So that Concrete will be on either side of the steel, add maximum strength to the structure.
Water reducing agent and concrete flexibility agents and steel composites resisting Agents to be poured in the proper proportion to have a better connecting effect.
Strength of concrete :
Calculates in N/mm2. A rich mix concrete of 1: 1½: 3 ratio, with proper additives will result 80% more strength, with an extra cost of 25% or otherwise 125% of the cost will yield 180% of strength.
Cube testing is to be done for every concreting, three cubes should result identical figure in the 7th day. It shows 58% the final strength of the concrete, which is attainable on 28th day (98%)
Concrete- 20N/mm2 –Cost Rs.3200 /-