Experimental Study on Hydration Heat Control of Mass Concrete by Vertical Pipe Cooling Method

Abstrct Thermal cracking of slender mass concrete in attached walls, retaining walls and bridge towers, is controlled by mainly using low heat cement and the control joint. However, it is impossible to control thermal cracks perfectly because the external restraint is largely in these mass concrete members. In this study, to control the thermal cracking of slender massive concrete structures, a new pipe cooling method, which is the vertical pipe cooling method, was developed and a mock-up of a wall-type mass concrete specimen was tested to investigate the validity of this method. Each pipe is connected to the header pipe, and a drainage control cap is installed at the upper end of each pipe. As a result, the hydration heat of the pipe cooling specimen was about 8–14°C lower than that of the non-pipe cooling specimen and the tensile stress generated was smaller in the pipe cooling specimen than in the non-pipe cooling specimen. In the specimen without pipe cooling, a penetrating crack with a maximum width of 0.40 mm and length of 1250 mm occurred in the middle of the specimen.