Plastic concrete cutoff wall technology has been successfully applied to those water-control engineering projects with higher requirements for seepage control. The quantity and quality of clay, aggregate and cement, determine the appropriateness of plastic concrete. Therefore, in this study, laboratory tests of four diverse mix designs with bentonite and sepiolite clay materials were conducted to determine the most suitable material for concrete. By increasing the clay and cement content, a change was observed in the specimen properties; this change became more obvious with increase in specimen age. By increasing the silt and clay content, there was a noticeable reduction in compressive and tensile strength. The mechanical properties variation of concrete produced with sepiolite is comparable to concrete made with bentonite, which can be recommended under the condition of available sepiolite material and seepage water with high contamination. The improvement and modification of physical specifications of plastic concrete, such as strength permeability and metal adsorption, reduced cracks and increased the operating life of concrete for a variety of engineering structures. (C) 2016 Published by Elsevier Ltd.