Research And Application Of Environmentally Friendly Green Growing Porous Concrete

With the great demand in materials with the benefits to environmental conservation, ecological variousness and continuable development, green-growing porous concrete is investigated as one kind of the environmental-friendly ecological concrete. Green-growing porous concrete contains a particular system of continuous porous structure. And the continuous porous structure provides the possibility of excellent permeability and ventilation of concrete. Therefore green plants are able to grow directly on the surface of green-growing porous concrete. Based on the requirements of the demonstration project, the research and study is mainly including the investigation of mix proportion and specimens molding, the test and discussion of basic mechanical properties, the design of construction unit molds for slope maintenance and the technique development of green plants growth on porous concrete. The range of cementitious binder fluidity control is the key to design the feasible mix proportions. It proves that the most appropriate range of cementitious binder fluidity control is from 150mm to 200mm and simultaneously the water binder ratio is kept between 0.21 and 0.30. Based on the preparation of fluidity control and water binder ratio control, the porous concrete is perfectly molded with four steps mix procedures and moulding techniques of tamping and surface compaction. Fresh concrete has no fluidity and its specific weight varies from 1800 kg/m3 to 2000 kg/m3 with different spacing ratios. The permeability of green-growing porous concrete is even better than ordinary soil with comparing both permeability coefficients measured by an apparatus made in our lab. It's also drawn from the experimental research that mineral addition partially replacing cement reduces PH value in concrete spacing and improves concrete strength. For instance, with the addition of silicon fume at weight fraction 2%, the porous concrete compressive strength reaches to 28.7MPa and flexural strength arrives at 2.9MPa at curing age of 28 days with a decline in PH value to 10. The project investigation achievement entirely fulfills the Japan criteria of green-growing porous concrete for rival maintenance. According to the requirements for rival maintenance, it presents three different construction unit molds designed for various demands, which are porous concrete ball, squarely four-linked porous concrete balls and porous concrete brick. Molds are all designed and manufactured in our lab.It discusses the effects on green plants growth on porous concrete surface of various factors, such as planting methods, circumstance conditions and plant species. The experiment consequences indicate that green plants grows perfectly well on the porous concrete surface with the planting matrix (composed of matrix, nutrient solution, densification agent and plant seeds) filling in concrete inner spacing and with appropriate curing and management.