Study On Performance Of Regenerated Aggregate Vegetated Concrete

The vegetated concrete not only has the traditional concrete berm and slope protection function,but also is an ecological concrete that can reduce the environmental load and natural coordination.In order to promote the development and construction of "sponge" cities,realize the functions that modern cities should have,improve the urban environment,and research and develop a plant-type porous ecological permeable concrete that uses waste concrete as aggregates by reducing the amount of cement used in concrete.,to reduce the alkalinity,so that it consumes a large amount of urban construction waste,achieve high water permeability of concrete,good greening performance,excellent durability,making it conducive to preparation and growth,realizing vegetation ecological concrete to protect water and soil,conserving water source,and sound absorption Noise reduction,beautification of the environment.In this paper,high-volume superfine ore fines are used as admixtures and waste concrete as recycled aggregate to prepare vegetated concrete.The ultrafine mineral powder content,aggregate gradation,porosity and water-to-binder ratio are applied to the mechanical properties of vegetated concrete and water permeability.The effects of sex and frost resistance were studied,and XRD,SEM and industrial CT were used to study the changes of hydration products and pore structure of different proportions of planted concrete.At the same time,the growth status of tall fescue,ryegrass and white clover in the vegetative concrete environment was verified.Studies have shown that the incorporation of ultrafine mineral powder can reduce the mechanical properties of the vegetated concrete and reduce the alkalinity.When the superfine ore powder is 60%of the mass of the cementitious material and the porosity is 20%,the 28d compressive strength is reached.10MPa,the pH of the leachate is 10.08,which is a good balance point between mechanical properties and alkalinity.The mechanical strength of vegetated concrete decreases with the increase of porosity.When the water-to-binder ratio varies from 0.23 to 0.29,it increases first and then decreases with the increase of water-to-binder ratio.The mechanical properties and frost resistance of single-graded vegetated concrete are better than continuous grade.The permeability coefficient of vegetated concrete increases with the increase of porosity of vegetated concrete,and the permeability of single grading concrete is continuous gradation;the permeability coefficient is one order of magnitude lower than that before perfusion,but still much higher than that of ordinary soil.It has been found by CT technology that the pore size distribution of porous concrete is very large.The scanning of different grades and different porosity concretes was carried out by industrial CT,and the three-dimensional model was reconstructed.The pore structure was analyzed by VG Studio Max software.The range and distribution ratio of pore diameter in vegetated concrete,the ratio of the volume of pores of different diameters to the total pores,and the relationship between pore shape and pore size were obtained.A 50mm thick vegetated concrete slab was prepared and subjected to a phytosanitary test in actual soil.The growth status of tall fescue,ryegrass and white clover in vegetative concrete environment was verified.In the test,the vegetative substrate was poured into the gap of the vegetated concrete to ensure the nutrition of the grass seed at the initial stage.The test lasted for three months.During the test,all three grass species can grow in the environment of vegetated concrete.Only the white clover germination rate is low,and the root system is not easy to protrude into the pores of the vegetated concrete.In the vegetated concrete environment,the grass can be germinated within one week and can be flattened in about three weeks.