EPS混凝土静态力学性能及本构模型研究

发布时间：2018-03-10 18:07

本文选题：EPS混凝土　切入点：静态力学性能　出处：《太原理工大学》2017年硕士论文　论文类型：学位论文

【摘要】：聚苯乙烯(Expanded Polystyrence,简称EPS)混凝土是一种环境友好型的新型建筑材料,由于其具有轻质和保温隔热性能良好的特点,目前已被广泛地应用于建筑工程中。因此,其力学行为和本构模型成为混凝土材料学科的研究热点。本文首先试验研究了不同粒径(0.5-1mm、2-3mm、5-6mm)、不同置换率(25%、50%、75%)的EPS混凝土静态压缩、劈裂和抗折性能。分析了不同置换率下EPS混凝土的压缩应力应变曲线;分析了置换率对抗压、劈裂和抗折性能的影响;研究了EPS粒径对混凝土静态力学性能的影响;建立了相对抗压强度、相对抗拉强度与相对密度的关系;采用单孔试验研究了EPS颗粒粒径对混凝土力学性能的影响机理,推导出粒径大小对混凝土强度影响的理论表达式,使用试验数据验证了理论模型的有效性。选取粒径为0.5-1mm、置换率为50%的EPS混凝土作为参照试验,按照纤维掺入量为0.8kg/m3、1.3 kg/m3和1.8 kg/m3掺入聚丙烯纤维,对试件的抗压强度、劈裂抗拉强度和抗折强度进行测试。分析抗压、抗拉和抗折强度随纤维掺量的变化规律,并进一步分析纤维对EPS混凝土力学性能的影响机理。选取粒径为0.5-1mm,EPS置换率为50%、75%的两组EPS混凝土作为参照试验,以机制砂等质量置换EPS混凝土中的天然河砂,置换率为0、20%、40%、60%、80%。对EPS混凝土抗压强度和劈裂抗拉强度进行测试。分析抗压和抗拉随机制砂置换率的变化规律并进一步分析机制砂对EPS混凝土力学性能的影响机理。基于弹性损伤和经典塑性力学,参照普通混凝土的受压损伤本构模型,提出使用双折线损伤本构模型来描述混凝土的应力应变关系,通过试验所测数据确定本构模型的特征参数。并把损伤本构曲线和试验所得应力应变曲线进行对比,两者吻合较好,初步验证了该模型的有效性。为研究EPS混凝土在复杂载荷作用下的本构模型打下基础。
[Abstract]:Polystyrene expanded Polystyrene (EPS) concrete is a new kind of environment-friendly building material. It has been widely used in construction engineering because of its good properties of light weight and heat insulation. Its mechanical behavior and constitutive model have become a hot research topic in the field of concrete materials. In this paper, the static compression of EPS concrete with different diameters of 0.5-1mm ~ 2-3mm ~ 5mm ~ 6 mm and different displacement ratio of 25mm ~ 50mm / 75) has been studied. The compressive stress-strain curves of EPS concrete under different displacement rates are analyzed, the effects of displacement ratio on compressive, splitting and flexural properties are analyzed, and the effects of EPS particle size on static mechanical properties of concrete are studied. The relationship between relative compressive strength, relative tensile strength and relative density is established, and the influence mechanism of EPS particle size on the mechanical properties of concrete is studied by single hole test, and the theoretical expression of the influence of particle size on concrete strength is deduced. The validity of the theoretical model was verified by using the experimental data. The compressive strength of the specimens was determined by adding 0.8 kg / m 31.3 kg/m3 and 1.8 kg/m3 polypropylene fibers to EPS concrete with a diameter of 0.5-1mm and a replacement ratio of 50%. The splitting tensile strength and flexural strength were tested. The variation of compressive, tensile and flexural strength with fiber content was analyzed. The influence mechanism of fiber on mechanical properties of EPS concrete was further analyzed. Two groups of EPS concrete with a diameter of 0.5-1 mm and a replacement ratio of 50% or 75% were selected as reference tests, and the natural river sand in EPS concrete was replaced with machine-made sand of equal mass. The compressive strength and splitting tensile strength of EPS concrete were tested. The change of replacement rate of compressive and tensile random sand making was analyzed, and the influence mechanism of mechanism sand on mechanical properties of EPS concrete was further analyzed. For elastic damage and classical plastic mechanics, Referring to the compressive damage constitutive model of ordinary concrete, a double broken line damage constitutive model is proposed to describe the stress-strain relationship of concrete. The characteristic parameters of the constitutive model are determined by the experimental data, and the damage constitutive curve is compared with the stress-strain curve. The validity of the model is preliminarily verified, which lays a foundation for studying the constitutive model of EPS concrete under complex loads.
【学位授予单位】：太原理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TU528

【参考文献】