Pore Structure Characteristics Of Grass-planting Concrete And Its Effect On Herbaceous Root Architecture

River plays an important role in urban drainage and flood control and water diversion and drought resistance.As a new type of ecological material for constructing bank revetment,the structure characteristics of grass planting concrete not only affect the strength,but also directly affect the growth space and growth path of plant roots,thus affecting the growth of plants.Therefore,it is of great significance in pore structure design and engineering application to further study the pore structure of grass-planted concrete and its influence on root configuration of herbaceous plants.In this paper,the volume method is used to design the mixture ratio of grass-planted concrete.Through the determination of compressive strength and porosity,the dry density test,a CT scan,vegetative,reveals the grass to the relationship between the physical and mechanical properties of concrete and the influence of pore structure on the configuration of herbal root,using ABAQUS to plant grass concrete to build 3 d simulation model and finite element model analyzed the mechanics and the relationship between the porosity,specific conclusions are as follows:(1)The effective porosity of the grass-planting concrete test block produced in this paper is close to the target planting,and the difference is only between 0 and 1.9%.Within the error range,the 28 d compressive strength is between 3 and 13 MPa,which can meet the basic requirements of the project.The compressive strength value decreases with the increase of the target porosity,showing a negative correlation,and increases with the increase of the amount of cementing material,showing a positive correlation.Effective porosity was negatively correlated with total amount of cementite,dry bulk density and compressive strength.(2)According to the CT sequence image analysis,the number of pores in the range of 10-100mm2 accounts for more than 30% of the total number of pores.With the increase of porosity,the total number of pores decreases and the number of pores in a large area increases.By extracting material,concrete three-dimensional finite element model is established,the control block elastic modulus,poisson’s ratio,constraint and load conditions,compared to the same water-cement ratio and effective porosity of different groups of five block in the maximum stress reached 10 MPa need displacement,the displacement range decreases with increasing of effective porosity,and can be directly against the compressive strength value of the test block.(3)According to the analysis of root configuration parameters,when plants grow ingrass-planted concrete,the root length will be affected to some extent,but the plants can grow normally in grass-planted concrete.When the concrete thickness is the same,with the increase of effective porosity,the total root length,total root surface area and root tip number will increase,while the maximum root length,average diameter and total volume will increase first and then decrease with the increase of porosity.When the target porosity of the test block is the same and the effective porosity is approximate,with the increase of the thickness of the concrete test block,the maximum length of the root and the number of root tips are affected,while other configuration parameters are not significantly affected when the thickness changes.