Efficiency of the Use of Set-Retarding Superplasticizers in Hot Climates PDF

Keywords

climates, superplasticizers, concrete, cement

Abstract

This paper examines the efficiency of the use of set-retarding superplasticizers in concrete and cement mixes for the purpose of reducing water content. Water-cement ratio was reduced from 0.6 to O.S for the concrete mixes and from 0.27 to 0.205 for cement pastes. Five different tests were performed: setting times, workability, compressive strength, porosity and water absorption. With the exception of workability batches, all samples were cured at 20°C, 35°C and 50°C. Three different curing regimes were employed; air curing, 3-day water curing and continuous water curing. Workability was measured both indoors (20°C + 65% RH) and or outdoors (38°C + 50% RH). Results indicate that high temperatures accelerate setting, workability loss and strength development but 28-day strength results were lower when compared to normal temperatures. The inclusion of superplasticizers improved the hardened concrete properties due to the lower wlc ratio but these improvements were smaller at high temperatures.