Fineness test of cement by dry sieving

Fineness test of cement as per IS 4031 – Part 1

Fineness of cement has a great effect on the rate of hydration and subsequently the rate of gain of strength. Fineness of cement improves the rate of evolution of heat. Finer cement offers a more surface area for hydration and hence faster the development of strength. Increase in fineness of cement additionally increases the drying shrinkage of concrete and and so creates cracks in structures. Excessive fineness Continue reading

Labor output constants for building works

Recommendation for labor output constants for building works in India

construction labor outputThe labour constants have been arrived at by the Central Building Research Institute, Roorkee by taking actual observations, using work measurement techniques, on the construction sites, Different types of building works up to 10 m height were included where the workers from neighboring states were working.

Following table shows recommendation for labor output constants for building works in India

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compressive strength test of concrete

compressive strength test of concrete -step by step procedure as per Indian standard code

Apparatus

compressive testing machine should be reliable, of sufficient capacity and able to apply the load at approx 140 kg/ sqcm per minute. The permitted error should be limited to maximum +/- 2 % of maximum load.

concrete compressive testing machine

Age at test

compressive strength testing shall be done at definite age the most common being 7,15 and 28 days. In case of urgency to calculate strength, the test may be done after 24 hours (+ / – 1/2 hours) and 72 hours ( + / – 2 hours). It is Continue reading