thre are 2 types of expansion in cement. I want to know the details of them & which expansions occures first & when ? Which exoansion occurs later on & when? Can we judge when the crack or the expansion will occur ? If yes how? raj
Dastgir
Dear XXXX,
Following reaction are considered expansive in cement concrete -
1. CaO+H2O = Ca(OH)2
2. MgO + H2O = Mg(OH)2
3. SO3(If in excess, after hardening) +C3A = ettringite
4. Alkali+ Aggregates(Incase of active SiO2) = Alkali silicates
Though i am not much aware their time of expansion manifestation , but first one is one which occur at the earliest and second one at last.
Regards,
Gulam Dastgir