Effects of Water-Binder Ratio and Coarse Aggregate Content on Interior Humidity, Autogenous Shrinkage, and Drying Shrinkage of Concrete

Experimental studies on shrinkage and interior humidity of three series of concrete with three aggregate contents in each concrete under sealing and drying conditions were carried out. The results show that the development of interior humidity of concrete is influenced strongly by the water-binder ratio and curing status of the specimen. In dry conditions, a fast reduction of the interior humidity is accompanied with a fast increase of shrinkage strain of the unsealed specimen compared with that of the sealed specimen. The effect of coarse aggregate on the interior humidity is insignificant. The difference in interior humidity between exposed and sealed specimens decreases with the reduction of the water-binder ratio. For a given age, the autogenous and drying shrinkages decrease with the increase of coarse aggregate content. The addition of coarse aggregate has a more significant influence on drying shrinkage than autogenous shrinkage.