Concrete strength

Concrete strength

Generally a concrete mix is required to provide a specified strength, the most common measure of concrete strength is the compressive strength determined in either a cube test or a cylinder test. The user can specify whether cube or cylinder strengths are to be used for the mix designs. The process of strength growth is called ‘hardening’ this is often confused with ‘setting’ but setting and hardening are not the same.

Setting is the stiffing of the concrete after it has been placed. A concrete can be ‘set’ in that it is no longer fluid, but it may still be very weak; you may not be able to walk on it, for example. Setting is due to early-stage calcium silicate hydrate formation. The terms ‘initial’ set’ and ‘final set’ are arbitrary definitions of early and later set; there are laboratory producers for determining these using weighted needles penetrating into cement paste.

Hardening is the process of strength growth and may continue for weeks or months after the concrete has been mixed and placed. Hardening is due largely to the formation of calcium silicate hydrate as the cement hydrates. The rate at which concrete sets is independent of the rate at which it hardens. Rapid – hardening may have similar setting times to Ordinary Portland cement. 
Post a Comment
Powered by Blogger.
Don't Forget To Join US Our Community