237 posts
TimePosted 17/10/2010 06:02:43
xxxx says

Expansion in cement

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


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108 posts
TimePosted 17/10/2010 07:53:37
Dastgir says

Re: Expansion in cement

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.


Gulam Dastgir