【作者】 张贵；

【导师】 尹健；

【作者基本信息】 中南林业科技大学 ， 土木工程， 2018， 硕士

【摘要】 生态多孔混凝土的孔隙结构及其特征直接影响植物根茎的生长空间、生长路径,决定其根系是否能够透过生态多孔混凝土板并伸入基层土壤,对植物的生长规律、生存周期及寿命有重要影响。通过分析生态多孔混凝土骨料的级配特征,结合孔隙率、等效孔径、平面孔隙率以及断面分形维数等孔隙结构特征,探索了生态多孔混凝土孔隙结构与植被根系结构相容性的表征方法及其植生性能的评价指标,研究了生态多孔混凝土孔隙结构特征与透水性能、植生性能的相互关系,并提出了植被的种植工艺。研究生态多孔混凝土的孔隙结构与植物生长规律的结构相容性对完善生态多孔混凝土的制备技术体系、指导植被种植以及推动生态多孔混凝土的广泛应用具有重要意义。本论文取得的主要成果如下:(1)生态多孔混凝土的堆积模型可用“垛密理论”描述。基于垛密理论,提出了生态多孔混凝土的成型方法,构建了生态多孔混凝土模型的基本单元模型,并推导出由单一粒径骨料组成的五面体单元模型构成的生态多孔混凝土的空隙率计算公式;(2)基于相对动弹模量,定量表征出生态多孔混凝土的冻融损伤评价参数即冻融损伤变量DF,并导出了粉煤灰掺量分别为0%、10%、20%时,冻融损伤变量DF与冻融循环次数的函数关系式。该表征参数可有效评价生态多孔混凝土的冻融损伤程度或预估生态多孔混凝土的抗冻融破坏能力;(3)通过分析9.5～16 mm、16～19 mm、19～26.5 mm三粒级骨料生态多孔混凝土的开口孔隙率、等效孔径以及断面分形维数等孔隙结构特征,得出了粗骨料的粒径尺寸和粒径集中程度是影响生态多孔混凝土孔隙结构特征的关键因素;(4)通过探讨开口孔隙率、等效孔径、平面孔隙率以及断面孔隙分形维数与生态多孔混凝土透水性能的相互关系,得出了等效孔径可作为主要参数来评价生态多孔混凝土的透水能力;(5)提出了表征生态多孔混凝土孔隙结构与植被根系结构相容性的评价方法即“透砂系数法”,该方法可有效、合理地衡量生态多孔混凝土的植生性能;(6)根据湖南及其以南地区的气候特性以及生态多孔混凝土的孔隙结构特征,基于已选的四种亚热带典型草种及其生长特性,提出了生态多孔混凝土植被种植工艺,为生态多孔混凝土相关规程的制定奠定了基础。更多还原

【Abstract】 The pore structure and characteristics of eco-porous concrete directly affect the growth space and growth path of plant rhizomes,and decide whether their roots can penetrate into the soil through the concrete slab.In addition,they have an important impact on the growth law,life cycle and life span of plants.Through the analysis of eco-porous concrete aggregate gradation theory,combined with the porosity,pore size,porosity,fractal dimension of cross-section and other pore structure characteristics,the compatibility between pore structure and vegetation root was explored.And,the planting performance evaluation index of eco-porous concrete was investigated.Furthermore,the relation between the characteristics and permeable performance,the planting performance were discussed.Finally,the planting technology of vegetation was presented.The researchs were of great significance for improving the preparation technology system of eco-porous concrete,guiding vegetation planting and promoting the wide application of eco-porous concrete.The main achievements of this thesis are as follows:(1)The stacking model of eco-porous concrete can be described by "stacking density theory".Based on the "stacking density theory",the forming method of the eco-porous concrete have been put forward.The basic unit model of the eco-porous concrete was built,and the calculation formula of the porosity was derived from the eco-porous concrete with single particle size aggregate and the five plane body configuration;(2)Based on the relative dynamic elastic modulus,the freeze-thaw damage variable DF of eco-porous concrete was defined,and the function relation between the freeze-thaw damage variable DF and the number of freeze-thaw cycles was obtained when the fly ash content were 0%,10%and 20%respectively.This characterization parameter can effectively evaluate the degree of freeze-thaw damage,or predict the ability of freeze-thaw damage of porous concrete;(3)Through analysis of opening porosity,equivalent pore size and fractal dimension of eco-porous concrete with the grain-size-ranges of 9.5～16 mm,16～19 mm and 19-26.5mm repectively,it was concluded that the size of the coarse aggregate and the concentration of the particle size were the key factors affecting the pore structure characteristics of eco-porous concrete;(4)The relation between the opening porosity,equivalent pore size,plane porosity,fractal dimension of the pore and the permeability of the eco-porous concrete were discussed,and the equivalent pore size can be used as the main parameter to evaluate the water permeability of the eco-porous concrete;(5)The method of evaluating the compatibility of the pore structure of the eco-porous concrete and the structure of the plant root was put forward,that is,the method of permeability coefficient,which can effectively and reasonably measure the growth performance of the eco-porous concrete;(6)Based on the climatic characteristics of Hunan and its southern region and the pore structure characteristics of the eco-porous concrete,combined with the selected four typical subtropical grass species and their growth characteristics,the eco-porous concrete vegetation planting technology was proposed,which laid the foundation for the formulation of the relevant regulations of eco-porous concrete.更多还原