Study On The Basic Properties And Micro Structure Of Vegetation-type Regenerate Brick Concrete

With the development of modern society, the concepts such as sustainable development, Environment protection, biological diversity is growing in every corner of the society deeply,Vegetation type ecological concrete which can improve the ecological environment, reduce the burden on the environment, achieve the recycling of resources, promote economic and social coordination and sustainable development has received the favor and attention. At the same time, along with the development of urbanization in our country, the development of new socialist countryside construction, continuous construction and expansion of urban and infrastructure, a large number of buildings and facilities were demolished, with the result that is an unprecedented increase in the number of construction waste, recycled aggregate concrete which is in order to make the construction waste resource utilization came into being. When recycled aggregate concrete is used in the structure, the strength is not enough, the air and water permeability of vegetation-type concrete is limited by the compactness of natural aggregate when it is used for river bank slope protection, urban greening. Two kinds of ecological concrete each have advantages and disadvantages, combined with two kinds of concrete, we can combine recycled aggregate concrete and vegetation-type concrete into vegetation-type regenerate brick concrete with "Caramel treats" framework.Porous concrete that is suitable for plant growth is made of waste bricks, it is both to reduce the environmental load and to adjust the climate and beautify the environment when used in engineering.The concept of vegetation-type regenerate brick concrete is described in detail in this paper, on the basis of analysis of development and application of vegetation-type concrete and regenerate brick concrete in the domestic and foreign, through a lot of experiments and exploration we can determined the preparation process of concrete, and on this basis we can use innovative research ideas and test methods to explore the structural properties and the microscopic mechanism of this concrete. The topic will carry out planting experiment on the factors that influence the performance and the mechanism to explore the necessary conditions for the growth of plants.(1)By analyzing the special properties of waste clay brick aggregate, the preparation and strengthening technology of the regenerate brick aggregate are summarized in this paper, and for the particularity of the regenerate brick aggregate's low strength and micro cracks and the special structure of porous concrete, the preparation technology and maintenance method of the vegetation-type regenerate brick aggregate concrete are established.(2)The control variables test and orthogonal test were carried out on the mechanical properties and water permeability of the vegetation-type regenerate brick aggregate concrete. The results of the control variables test show that the water cement ratio, the target porosity and the size of aggregate have different influence on the strength and permeability, and established the relationship between target porosity and water permeability coefficient, the relationship between effective porosity and water permeability coefficient and Relationship between target porosity and effective porosity. Through the orthogonal experiment, we can see that target porosity has a significant influence on the mechanical properties and permeability, and the optimal mix ratio of the mechanical properties and the optimum mix ratio are obtained.Integrated two kinds of tests, the relationship of the three that is the compressive strength of concrete, the measured porosity and permeability is analyzed, then taking the balance point of the three as the goal,optimal mix ratio which has higher strength, reasonable water permeability and be suitable for plant growth is formulated.(3)In order to study the micro structure of this concrete, and to essentially understand its character and rule, this test introduces the modern micro test equipment scanning electron microscope in the microscopic research of the vegetation-type regenerate brick aggregate concrete, the morphology of hydration products, the defect and morphology of inter-facial transition zone between cement and recycled brick when concrete has different water cement ratio, different target porosity, fly ash, different curing age were observed and analyzed, and make comparative analysis with macroscopic properties performance. Test shows that this concrete has better interface transition zone structure, compact structure, abundant hydration products, the different water cement ratio, different target porosity, fly ash, and different curing age have certain influence on density and type and quantity of hydration products, and then affect the strength. Macro performance and morphology of micro-structure basically tallies.(4)Through the analysis of SEM diagram and assumption of central grains about concrete of Professor Wu Zhongwei, the structural model of vegetation-type regenerate brick aggregate concrete was summarized, the relationship between micro-structure and macroscopic properties was studied qualitatively, the effect of morphology of ITZ(interface transition zone) and core effect of coarse aggregate on the macroscopic properties of this concrete was explored. The analysis draws the conclusion that porous concrete has more negative core effect, and big core effect only is regenerate brick aggregate. In the future research, it should be the focus of negative core effect.(5)In order to study the plant growth characteristics of this concrete, on the basis of the preliminary study of water permeability and mechanical properties, planting experiment was carried out. On the basis of analyzing of the suitable conditions of plants, planting experiment has adopted a method that is the combination of overhead type and intermediate type.Respectively, the method of soaked with water and treated with FeSO4 was used to alkalinity reducing, And Bermuda-grass was planted on concrete with different porosity, then planting effect was compared and observed, and then we have to determine the suitable grass greening conditions which was further optimized, in order to be used in different engineering environment.