| 摘要 |
PURPOSE:To contrive an improvement in finishing of an external appearance by improving smoothness and precision of the surface of concrete, by a method wherein the title nonwoven fabric is constituted of three layers such as a smooth surface layer and an intermediate and back layers whose density is comparatively high and which, moreover, possesses a quantity of aeration and vertical water permeable factor falling within a specified range as a whole. CONSTITUTION:The title nonwoven fabric is constituted of three layers of an intermediate layer 1 which is comprised of a fiber layer 2 comprised of a synthetic fiber and synthetic fiber base fabric 3 and needle-punched, a surface layer 4 which is smoothened through thermal processing of a surface side of the intermediate layer 1 and a back layer 5 comprised by heat-treating a fiber comes out similarly on the back of the base fabric of the intermediate layer 1 through needle-punching. The nonwoven fabric formed of a three-layer structure possesses values of 2.0-0.5cc/cm<2>/sec and 10<-2>-10<-4>cm/sec respectively for a quantity of aeration and vertical water permeable factor. At the time of tamping of concrete, air bubbles come up through the concrete 8 flow into the intermediate layer 1 through the surface layer 4 as per an arrow and discharged through small holes 7 of a concrete shuttering 6 by passing through the upper part of the intermediate layer and the back layer. On the one hand, water separated from the concrete flows into the intermediate layer 1 through the surface layer 4, sucked by the intermediate layer 1 and drained downward as per an arrow. |
