engleski

POLYCARBOXYLATE ETHER BASED SUPERPLASTICISER FOR CALCIUM ALUMINATE CEMENT MORTARS

This work investigates the effect of polycarboxylate ether (PCE) based superplasticiserplasticiser onto the fresh and hardened properties of mortars based on commercial CACs. Mortar specimens were prepared aiming at constant workability ; PCE addition was varied as 0% ; 0.3% ; 0.6% and 0.9% of cement mass. The required water to cement ratio to maintain the workability of fresh mortar was recorded. Cohesion of the fresh mortar was improved by addition of methyl-cellulose, thus avoiding segregation induced by the superplasticiser action. As PCE significantly retard the setting time, Li2CO3 was investigated as an accelerator. Compressive and flexural strengths were tested after 1 day and 9 days cured at 23°C and after transformation of metastable hydration products at 60°C. Deleterious effect of transformation of metastable hydration products to stable ones on mechanical properties was successfully reduced by lowering of water to cement ratio while maintaining the workability. In conclusion, the usage of PCE showed promising superplasticizing properties for CAC based materials.

calcium aluminate cement; hydration; mechanical properties; rheology; setting time; superplasticiserplasticiser.

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