Improved method for controlling contraction in setting cementitious systems.

摘要

Contractions of aqueous hydraulic cement mixtures being controlled by the addition of a gas-generating agent such as dinitrosopentamethylenetetramine capable of generating gas in the mixture without the addition of activators or other agents, and which does not generate disagreeable or noxious ammonia fumes. The gas generation may be controlled over an extended period of time so that even slow setting cementitious mixtures may have their shrinkage or contraction inhibited during setting or hardening without the generation of ammonia fumes.
<??>An accelerator such as ferrous sulfate-heptahydrate may be added.