WATER-BARRIER LAYER AND ITS CONSTRUCTION METHOD

PROBLEM TO BE SOLVED : To provide a water-barrier layer which can effectively prevent drying shrinkage immediately after application and a method for constructing the water-barrier layer. SOLUTION : In the method, in the tip part of a hose for spraying bentonite-mixed earth in which sand 3 and bentonite 4 are mixed, an asphalt emulsion 5 is added into the bentonite-mixed earth, the mixture is sprayed on the ground to construct the water-barrier layer 11, and mastic 51 containing the asphalt emulsion 5 as a main component is sprayed on the surface of the water-barrier layer 11 to construct a protective layer 12.