2.3.2 Factors Affecting Bleeding
Rate of bleeding depends on the amount of free water in the concrete, permeability of the fresh concrete and the hydraulic pressure in the free water.
The amount of free water depends on water content and water retainability of the solid particles in the concrete
Permeability of the concrete varies with the structures of voids among the solid particles and the air content.
Bleeding capacity, or total bleeding volume, depends on the height of the placing lift, free water content in the concrete mixtures and contact stress. Smaller total bleeding volume is obtained for smaller placing lift, smaller free water content but higher contact stress. Mixture with large amount of free water is not always necessary to have large total bleeding volume if the contact stress among the solid particles is high so that the hydraulic pressure in the free water cannot be produced.