DETERMINATION OF OPTIMUM SUPERPLASTICIZER DOSAGE FOR HIGH PERFORMANCE CONCRETE USING THE MARSH CONE TEST
ABSTRACT
Superplasticizers form an integral part of High Performance Concrete (HPC), such as High Strength Concrete and Self Compacting Concrete, which have various structural applications. Addition of the superplasticizer aids in placing concrete in members with congested reinforcement and/or reduced dimensions, and provides better corrosion resistance and mechanical properties (strength, stiffness) by permitting the reduction of the water content. However, the dosage of the superplasticizer should be optimized and the appropriate product should be used in order to obtain the desired characteristics, without an excessive cost or harmful secondary effects such as low early strength and segregation. This calls for the optimization of the superplasticizer dosage, using a method such as the Marsh Cone test of pastes, which is used in the present work, for determining an appropriate superplasticizer dosage for concrete. The methodology followed is explained and illustrative results are given for a cement paste, with a new-generation polycarboxylic acid based superplasticizer, that is typical of HPC. A study of the variability of the results obtained from the test method has also been conducted.
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