Experimental simulation of bleeding under a high concrete column

The quality of fresh concrete and durability of hardened concrete are affected by the bleed water of the fresh mixture including internal and external bleeding. The concrete mixture is pressurized during pumping for transportation or placing at high height. Variation of pressure influences the bleeding properties such as the amount and rate of bleeding water, which are determined from the oedometric modulus and diffusivity of the concrete mixture. However, with the conventional test it is difficult to estimate the bleeding phenomenon of fresh concrete under high pressure based on the bleeding properties. This study proposed a prediction model and experimental setup to evaluate the bleeding of freshly mixed concrete under high pressure. The pressure change, compressibility, and flow-out bleed water were obtained, and their variation was discussed with bleeding properties according to different types of fresh mixtures.