Properties and Performance of Green Concrete

Green Concrete is a concrete on which plants such as grasses and bushes directly grow up. It is utilized for increasing the amount of the green around buildings and civil structures. It consists of no-fines concrete, water retentive material in the voids and a thin soil layer sprayed on the surface. The no-fines concrete is made of single size crushed stone and low alkaline cement paste. Chopped peat moss which retains water and fertilizer is used to fill in the voids. Seeds mixed with the soil germinate, take root into the voids and grow up. In this paper the results of studies of the relationship between the strength and the void ratio of concrete, and the effects of cement types on the alkalinity leached from hardened cement are presented. Plant growth performance of the Green Concrete is also presented based on planting tests using lawns and actual applications. The optimum void ratio of concrete was approximately 25-30% when the compressive strength was approximately 10-15 N/sq mm. In this condition of concrete, it is demonstrated that herbaceous plants and some kinds of trees sufficiently grow on the Green Concrete.