Study On The Preparation And Properties Of Lightweight Aggregate Planting Concrete

The construction of infrastructure and the rapid development of urbanization had caused more and more damage to the ecological environment,which in return had been acted on human society.In recent years,like landslides,debris flow and the reduce of human drinking water sources,All of which gave warnings to the human society.With the development of economy and society,soil and water conservation and water pollution control has been widely concerned by the government and society.So how to ensure the development of human society,at the same time,to protect water and soil resources is the important task of human beings.Planting concrete is a kind of environment-friendly material with special structure.The principle is to use the porous structure of concrete to plant green plants.The landscape effect of green plants is used to beautify the slope environment,and the concrete strong ability of concrete is used to enhance the ability of slope fix plant.Furthermore,the lightweight aggregate planting concrete is a kind of new building materials which is built on the basis of traditional planting concrete.Lightweight aggregate has better water and fertilizer retention and some lightweight aggregates can float on the surface of water,which can be used in the preparation of planting concrete floating bed,and then the application of concrete extended to water pollution control from the slope protection.In this paper,the properties of three kinds of lightweight aggregate planting concrete and the effect of three kinds of degradable aggregates on the performance of the concrete were studied emphatically.The effect of fertilizer on the release of fertilizer was studied by using the characteristics of porous aggregates.The low density of polystyrene particles and pumice was used to prepare the planting concrete floating bed,the effect of ecological floating bed on the eutrophic water was studied.This paper has made the following conclusions:(1)The adulteration of urea and diammonium phosphate in the planting concrete had an effect on its compressive strength.Urea reduced the early compressive strength of the planting concrete,diammonium phosphate reduced the compressive strength of all the age of the planting concrete,and the greater the dihydrogen phosphate content was,the more obvious the compressive strength decreased.Compared with the blank sample.the compressive strength of each age decreased by 76.8%,74.8% and 75.1%,respectively at 3.5 wt.%.After the adulteration of urea,the alkalinity of the planted concrete did not rise,and the pH value was close to 8.1 after 56 days.The alkalinity of samples with the diammonium phosphate were higher than that of the blank.(2)Planting concrete with fertilizers had a certain fertilizer release characteristics,the cumulative release rate of fertilizer increased with the dosing amount.The cumulative release rate of nitrogen in the samples with urea was 45.1% ~ 78.3%.The cumulative release rate of phosphorus in the samples with diammonium phosphate was only 0.12% ~ 0.34%.(3)The water-cement ratio suitable for the formation of pumice planting concrete was 0.33,but the pumice planting concrete can not float on the surface of water due to the higher water absorption of the pumice aggregate.(4)The incorporation of redispersible latex powder reduced the fluidity and early compressive strength of sulphoaluminate cement,and increased the viscosity of sulphoaluminate cement slurry.From the XRD pattern,its incorporation had a little effect on hydrated mineral of sulphoaluminate cement.From the hydration cumulative heat release,its incorporation inhibited the early hydration of sulphoaluminate cement.(5)The compressive strength and dry density of polyphenylene particles concrete decreased with the increase of aggregate-cement ratio,and the porosity and permeability coefficient increased with the increase of aggregate-cement ratio.Considering the compressive strength and porosity of concrete,0.09 is used as the suitable aggregate-cement ratio,and the diameter of 30 mm polyphenylene particles was selected to make concrete.(6)Three kinds of green aquatic plants were planted to purify the tested water.The compatibility of epipremnum aureum and myriophyllum aquaticum with floating bed was very well,and the survival rate of plants was more than 82%.The removal rate of TN were 78.3% and 80.2% respectively The removal rate of TP reached 62.3% and 69.2% respectively.The DO of the experimental water was increased from 2.78mg/L to 6.5mg/L.(7)To achieve the floating of concrete,the pumice needed to mix with polyphenylene particles,when the polystyrene particles accounted for more than 30% of the volume of concrete could achieved floating on the surface of water,in order to achieve high water purification efficiency,the proportion of polyphenylene particles was set to 50%.The dry density of the floating bed under this ratio was 352.43kg/m3.(8)Three species of green aquatic plants were planted to purify the experimental water.The compatibility of epipremnum aureum,myriophyllum aquaticum and coins grass with floating bed was very well,TN removal of three species of experimental water were 85.9%,88.1% and 76.1% respectively.The DO of the experimental water were stable at 7.2~8.3mg/L,nutrient rich and ecological floating bed itself also can absorb the eutrophic elements of water,which can improve the purification efficiency of floating bed on water eutrophication.(9)When the three kinds of degradable aggregates were mixed with the concrete,when the content is within a certain range,the compressive strength and dry density of the concrete increased with the increasing of degradable aggregates content,and after a certain range,the compressive strength of the concrete strength and dry density were significantly decreased,and the samples with corn cob decreased most..(10)Through two months of immersion experiments,it was found that the porosity of sample with corn increased by 2.39%,granular fertilizer was 1.21% and corn cob was 0.83%.At the same time,the nutrient release test was carried out and the release of nutrient elements was found: granule fertilizer> corn > corn cob.When the content of granular fertilizer was 5%,the total release amount of nutrient element was 5.5 times and 12.5 times higher than corn and corn cobs respectively.