Setting and hardening accelerating agent for siliceous hydraulic binders
AssigneeLafarge
InventorsPhilippe Leture, Jacques Chappuis, Bruno Latrasse
Life of this patent
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Abstract
Setting and hardening accelerating agent for siliceous hydraulic binders wherein: a) it is obtained by hydration, in the usual pressure and temperature conditions, and grinding of a siliceous hydraulic binder aqueous suspension; b) the suspension particles are sufficiently fine for the agent to meet the following test requirements: an aqueous suspension in a sedimentation specimen at 20.degree. C., containing 10 grams (dry weight) of the accelerating agent in 100 ml of water, must have a sedimentation deposit height at least equal to 50% of the initial height at the end of two days; c) it is in the form of an aqueous suspension.
Claims18
A calcium silicate hydrate accelerating agent for siliceous hydraulic binders, which comprises an accelerating agent obtained by hydration and wet grinding of an aqueous suspension comprising Portland cement and optionally containing gypsum;
- wherein the particles of the suspension are sufficiently fine so that an aqueous suspension in a sedimentation specimen at 20.degree. C. containing 10 grams dry weight of the accelerating agent in 100 ml of water has a sedimentation deposit height at the end of 2 days at least equal to 50% of the initial height;
- and wherein the accelerating agent is in the form of an aqueous suspension having a solids content from 5% to 55% by weight.
A method of accelerating the setting and hardening time of a paste of a siliceous hydraulic binder, said method comprising adding a calcium silicate hydrate accelerating agent to said paste, the improvement comprising:
- producing the accelerating agent by hydrating a siliceous hydraulic binder comprising Portland cement and, optionally, gypsum and grinding said hydraulic binder in an aqueous suspension to obtain an aqueous suspension with a solids content of from 5% to 55% by weight;
- and adding said aqueous suspension to said paste in a proportion of suspension to paste of 0.1% to 10% by weight, expressed as dry solids of said accelerating agent to the total weight of said paste;
- with the proviso that said wet ground solids in the accelerating agent have a particle size so that, at 20.degree. C. in a sedimentation specimen containing 10 grams by dry weight of accelerating agent in 100 ml of water, the sedimentation deposit height at the end of two days is at least equal to 50% of the initial height.
Dependencies are inferred from the claim text.