Effect of Super-plasticizer Dosages on Fresh State Properties and Early-Age Strength of Concrete

Concrete is the most widely used composite material made up of different ingredients i.e. aggregates (fine, course), cement and water. The early age properties of concrete like workability, setting time and initial strength are continuously changing due to its transient behavior. So it is important to improve the properties of fresh concrete as per the requirements of the structure. The early age properties of concrete control the hardened properties of concrete such as creep, durability and its performance. Admixtures are added to the concrete to achieve a desired change in its properties. This study focuses the effects of super-plasticizer (Duraplast SP-400) dosages on the early age properties of concrete. Six different mixes were prepared with varying SP dosages. Workability, setting time and concrete compressive strength were determined at early age. With the increase in SP dosage, concrete compressive strength at early age reduced however its strength at 28 days increased by adding SP dosage up-to 2%. Workability and setting time were increased but their values decreased down beyond 2 % dosage.