酸雨环境侵蚀下箍筋约束混凝土本构关系试验研究

发布时间：2018-11-01 12:13

【摘要】：酸雨侵蚀钢筋混凝土结构的化学反应过程相当复杂，一旦混凝土材料受到酸雨溶液的侵蚀，会随着侵蚀程度的增加，材料结构自身的性能发生退化。混凝土内部的许多化学成分都会参与到化学反应中，结构的微观和宏观会随之发生变化，使混凝土的力学性能退化严重，，导致其使用寿命的下降，影响到人们的生产与生活质量。近二十年来，对于钢筋混凝土结构受酸雨侵蚀的研究主要集中在混凝土材料的损伤机理、宏观微观性能及退化规律等方面，对钢筋混凝土构件整体工作性能研究较少，对于酸雨环境下约束混凝土应力-应变关系的研究至今未见到。钢筋混凝土构件受酸雨侵蚀后其内部钢筋与混凝土的协同工作能力会受到严重影响，这样钢筋混凝土构件中配置的箍筋对混凝土产生的横向约束作用就会被大大削弱，特别是变形能力也将出现衰减。从而对钢筋混凝土构件和结构的抗震性能分析会产生很大影响，故本文对受酸雨侵蚀后的约束混凝土本构关系进行试验研究具有重要的理论意义和应用价值。（1）对酸雨环境侵蚀下箍筋约束混凝土应力-应变本构关系试验研究，本文设计了共48个尺寸为150mm×150mm×450mm的钢筋混凝土棱柱体试件进行了四种不同酸雨环境的腐蚀，试件的变化参数为酸雨环境中的PH值、SO42-浓度、配箍特征值、腐蚀时间。四种环境分别为酸雨环境A（PH值4.5、 SO42-0.002mol/L）酸雨环境B（PH值3.0、SO42-0.002mol/L）酸雨环境C（PH值3.0、SO42-0.06mol/L）酸雨环境D（PH值1.0、 SO42-0.1mol/L）.并对受侵蚀后的试件进行了轴压破坏试验，通过试验绘制出实测的约束混凝土的应力-应变曲线。（2）通过回归得到的腐蚀后箍筋约束混凝土单轴受压应力-应变曲线的上升段分成了两部分，上升段的前半部分属于平缓阶段，呈现凹曲线形式，斜率很小；上升段后半部分和下降段与未腐蚀混凝土曲线形状基本一致。受侵蚀后的曲线整体形状变尖，下降段变陡。本文依然采用传统的两段式（上升段与下降段）来建立酸雨腐蚀下箍筋约束混凝土应力-应变曲线。（3）试验分析了腐蚀混凝土的弹性模量、峰值应力、峰值应变、极限应变的变化情况。并引入了反映腐蚀介质、配箍特征值和腐蚀时间作为参数，并涉及到酸化深度，借助试验数据确定上升段与下降段方程与相关参数的表达式。综上所述，建立的酸雨环境侵蚀下约束混凝土本构模型能准确地反映侵蚀溶液浓度、侵蚀时间、配箍特征值及酸化深度对材料力学性能的影响。研究成果诸如回归得到的本构关系方程及确定其参数的公式等，可以适用于西南酸雨区受酸雨侵蚀的钢筋混凝土结构、构件的非线性分析。
[Abstract]:The chemical reaction process of acid rain eroding reinforced concrete structure is very complex. Once the concrete material is eroded by acid rain solution, the properties of the material structure will degrade with the increase of erosion degree. Many chemical components in concrete will participate in chemical reaction, and the microstructure and macro will change with it, which will make the mechanical properties of concrete degenerate seriously and lead to the decline of its service life. Affect people's production and quality of life. In the past twenty years, the research on the corrosion of reinforced concrete structures by acid rain has mainly focused on the damage mechanism of concrete materials, macroscopic and microscopic properties and degradation laws, etc., and less on the overall working performance of reinforced concrete members. The stress-strain relationship of confined concrete in acid rain environment has not been studied. After the reinforced concrete members are eroded by acid rain, the synergistic ability of reinforcing bar and concrete will be seriously affected, so that the transverse restraint effect of the stirrups in reinforced concrete members on concrete will be greatly weakened. In particular, deformability will also be attenuated. Thus, the seismic behavior analysis of reinforced concrete members and structures will have a great impact, so it is of great theoretical significance and practical value to study the constitutive relationship of confined concrete after acid rain erosion in this paper. The main contents are as follows: (1) the stress-strain constitutive relation of stirrups confined concrete under acid rain environment is studied. A total of 48 reinforced concrete prism specimens with size of 150mm 脳 150mm 脳 450mm have been designed for corrosion in four different acid rain environments. The variation parameters of the specimen are PH value, SO42- concentration, hoop characteristic value and corrosion time in acid rain environment. The four kinds of environment are acid rain environment A (PH value 4.5, SO42-0.002mol/L) acid rain environment B (PH value 3.0 so 4 2-0.002 mol / L) acid rain environment C (PH value 3.0, SO42-0.06mol/L) D (PH value 1.0, SO42-0.1mol/L in acid rain environment. The axial compression failure test was carried out on the corroded specimens, and the stress-strain curves of confined concrete were drawn. (2) the rising section of the uniaxial stress-strain curve of corroded stirrups confined concrete is divided into two parts. The first half of the rising section belongs to the gentle stage, showing concave curve form, and the slope is very small; The shape of the curve of the latter half of the rising section and the descending section is basically the same as that of the uncorroded concrete. After erosion, the whole shape of the curve becomes sharp and the descending section steepness. In this paper, the stress-strain curve of stirrups confined concrete under acid rain corrosion is still established by using the traditional two-stage formula (up-and-down section). (3) the variation of elastic modulus, peak stress, peak strain and limit strain of corroded concrete are analyzed. The equation of rising and descending stage and the expression of relevant parameters are determined by means of experimental data. The corrosion time and characteristic value of hoop are used as parameters and the acidizing depth is involved. To sum up, the constitutive model of confined concrete under acid rain environment can accurately reflect the influence of the concentration of erosion solution, the time of erosion, the characteristic value of hoop and the acidizing depth on the mechanical properties of materials. The research results, such as the constitutive equation obtained by regression and the formula for determining its parameters, can be applied to the nonlinear analysis of reinforced concrete structures and members affected by acid rain in the southwest acid rain area.
【学位授予单位】：西安建筑科技大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TU375

【相似文献】