Sustainable Concrete in the Construction Industry of Kurdistan-Iraq through Self-Curing

Abstract

The improper curing of concrete can seriously affect its hardened properties. However, a large quantity of water is required to cure concrete after casting. Water is a valuable resource and its availability is posing a particular challenge in the Middle East including the Kurdistan region of Iraq. Self-curing concrete may be considered a novel curing method in that the water inside the concrete mix is retained so that hydration can continue without the supply of additional water after casting. Therefore, the aim of this study was to include a self-curing agent, named Polyethylene glycol-400 (PEG-400), as one of the concrete mix constituents in order to save water that is normally required after casting. Six concrete mixes were cast with a constant W/C ratio of 0.5; two of them were ordinary concrete mixes whereas the other mixes contained 0.5%, 1%, 1.5%, and 2% of PEG-400 by weight of cement. All concrete ingredients, except the PEG-400, were provided locally. Three different curing regimes were employed: air curing under ambient laboratory conditions, water curing, and self-curing using different dosages of PEG-400. Testing included compressive strength, ultrasonic pulse velocity (UPV), and water absorption. The results showed that 1% of PEG-400 is the optimum dosage to be used for self-cured concrete.