Effect of superplasticizer content and temperature on the fluidity and setting of cement pastes

The effect of the ambient temperature (over a range of 5 to 45 degreesC) on the fluidity or superplasticized cement pastes has been studied using the Marsh cone test. The results indicate that the fluidity increases with an increase in temperature but the maximum (or saturation) dosage of the superplasticizer is not. This tendency is not, however, observed in stiff pastes studied using the Vicat test for normal consistency, where the water demand increases with an increase in temperature. The effect of temperature on the loss of fluidity with time has also been analysed showing that the two superplasticizers used here do not lead to significant losses over a period of 90 minutes after mixing. The consequential phenomenon of setting has been studied through electrical impedance measurements and penetration tests with the Vicat apparatus.