Strengthening of Hydrothermal Hot-Pressed Concrete Wastes by the Addition of Fresh Cement

Abstract

In order to recycle concrete wastes, a new processing method for solidifying pulverized concrete wastes has been developed using a hydrothermal hot-pressing method. The effect of addition of fresh cement was examined to further increase the strength of solidified concrete wastes. Hydrothermal hot-pressing tests were carried out at 200-250°C with the water content of 10-30 mass% under the pressure of 20MPa for 20 min. Fresh cement of 0-50 mass% was added to the mixture. It is shown that the formation of tobermorite improved the tensile strength. The tensile strength determined by a Brazilian test reached approximately 13MPa under the conditions; the temperature: 230°C, fresh cement content: 50 mass%, and water content: 30 mass%.