Estimating An Appropriate Plastic Concrete Mixing Design For Cutoff WallsTo Control Leakage Under The Earth Dam

Making use of concrete materials in cut-off walls, because of their low permeatabilty and standing high Hydraulic Gradient caused by underground drainage, has traditionally received great amount of attention. Using ordinary concretes with high elasticity modulus, compared to other materials that could be found nearby, may accompany with problems including brittleness of cutoffs due to due to dynamic stress. To solve this problem, adding a certain percentage of clay (Betonite) to plastic concrete materials reduces the concrete hardness as well as its elasticity coefficient, resulting in better ductility. Adding Ebonite (clay and excavation mud) decreases the possibility of hydraulic failure and cracking. Present article analyzes plastic components of the concrete and parameters which affect properties and manner of its mixing design. Based on the results that have been obtained from experiments on plastic concrete samples which have various mixing plans, certain diagrams have been presented to obtain an ideal mixing plan for plastic concretes which result in determining a key relationship to be able to estimate an appropriate mixing of cutoffs to control leakage under the dam. While under current situation, using these relationships to estimate the appropriate mixing for plastic concrete in order to control leakage under the dam is costly and time consuming with considerable amount of errors.

Keywords:

Plastic Concrete , permeability , ductility , , elasticity modulus