再生混合混凝土的受压尺寸效应及外置薄钢板再生混合墙的抗震性能研究

发布时间：2018-03-01 18:05

本文关键词： 废弃混凝土尺寸效应裂缝发展再生混合墙抗震性能　出处：《华南理工大学》2013年博士论文　论文类型：学位论文

【摘要】：再生骨料混凝土是废弃混凝土循环利用的一条有效途径，但再生骨料的生产过程较为繁琐且能耗较大，，加之再生骨料混凝土的配制仍需耗费大量水泥。为此，课题组提出了在结构构件中直接采用大尺度废弃混凝土的思想，从而将废弃混凝土的回收利用从骨料层次提升一至两个数量级到达大尺度块体或节段层次。课题组前期曾对采用大尺度废弃混凝土块体或节段的再生混合混凝土及其构件性能进行了初步研究，在此基础上本文进一步开展了再生混合混凝土受压尺寸效应以及外置薄钢板再生混合墙抗震性能两方面探讨。本文主要工作包括：通过51个再生混合混凝土立方体试件和36个圆柱体试件的受压试验，揭示了试件外形尺寸、废弃混凝土块体特征尺寸等因素对再生混合混凝土抗压强度、弹性模量和峰值应变的影响规律。研究表明：在特征比保持不变的情况下，再生混合混凝土组合抗压强度随试件外形尺寸的增大而减小，既符合尺寸效应律也满足修正的尺寸效应律；在试件外形尺寸保持不变的情况下，组合抗压强度随特征比的增大而减小；建立的组合抗压强度与特征比之间的定量关系与试验结果吻合良好；构建的组合抗压强度预测公式可同时考虑试件外形尺寸和废弃混凝土块体特征尺寸的变化且具有较好精度；试件外形尺寸和废弃混凝土块体特征尺寸对再生混合混凝土弹性模量和峰值应变的影响有限。利用数字图像相关(Digital Image Correlation，简称DIC)测量技术对再生混合混凝土的受压破坏过程进行了揭示，研究表明：废弃混凝土块体与新混凝土之间的界面并未出现明显的裂缝集聚萌发及扩展现象，裂缝的后期发展多以贯穿新混凝土和废弃混凝土块体的方式进行。通过7片外置薄钢板再生混合墙的拟静力试验研究，分析了废弃混凝土取代率、钢板厚度、轴压比、横隔板间距、高宽比等参数对试件抗震性能的影响。基于新、旧混凝土的组合强度，对试件的水平承载力进行了近似计算分析，并在总用钢量基本一致的情况下与钢筋混凝土墙的水平承载力进行了对比。研究表明：废弃混凝土取代率在0～33%之间变化对试件的初始刚度、水平承载力、破坏位移角、耗能能力、滞回曲线形状等抗震性能影响有限；外置薄钢板再生混合墙的设计轴压比不宜超过0.35；在墙厚与钢板厚度之比高达120的情况下，外置薄钢板再生混合墙仍具有较稳定的滞回性能和变形能力，其破坏位移角满足现行抗震规范要求；外置薄钢板再生混合墙具有与钢筋混凝土墙相当甚至略高的耗能能力；在总用钢量基本一致的情况下，外置薄钢板再生混合墙具有与钢筋混凝土墙基本相当的水平承载力。采用ABAQUS通用软件，建立了外置薄钢板再生混合墙的有限元模型，考察了主要参数对该类构件水平力—水平位移曲线的影响，并与试验结果进行了对比。对比计算时，考虑了再生混合混凝土组合抗压强度的尺寸效应。研究表明：单调加载时外置薄钢板再生混合墙的水平力—水平位移计算曲线上升段与往复加载试验骨架曲线总体吻合较好，但计算曲线的下降段与试验骨架曲线差别明显；在新、旧混凝土强度差小于10MPa时，废弃混凝土取代率在10%～40%之间变化对外置薄钢板再生混合墙的水平承载力和初始刚度影响较小；从用钢量角度考虑，单纯加厚墙端边缘约束构件（方钢管）对提高外置薄钢板再生混合墙的水平承载力可能更为有效；从方便废弃混凝土块体施工和提高该类构件水平承载力两方面考虑，建议实际工程中横隔板间距与墙厚之比取为1.0～2.0。
[Abstract]:Recycled aggregate concrete is an effective way to use the waste concrete, but the production process of recycled aggregate is complicated and large energy consumption, and the preparation of recycled aggregate concrete still needs to consume a large amount of cement. Therefore, this paper proposes the direct use of large scale waste concrete thought in the structure, enhance the aggregate level from one to two a number of large scale to block or segment level to recycle the waste concrete. Ourprevious was on a large scale waste concrete blocks or segments of the mixed recycled concrete and its components are studied, on the basis of the further development of the size effect of concrete mixing and compression of thin external regeneration to investigate the regeneration performance of hybrid steel plate wall two.
The main work of this article includes:
Through the 51 mixed recycled concrete specimens and 36 cylinder test compression test pieces, reveals the specimen size, waste concrete block feature size and other factors on the compressive strength of recycled concrete mixing, influences of elastic modulus and peak strain. The study shows that the characteristic ratio remained unchanged in the case of recycled mixture concrete compressive strength decreases with the increase of specimen size, both with the size effect law also meet the size effect law amendment; the specimen size remains unchanged, with the combination of characteristics of compressive strength ratio increases; the combination of compressive strength and characteristics are in good agreement with the quantitative relationship between the with the test results; combined forecasting of compressive strength formula can be considered at the same time try to build change the size and shape of waste concrete block feature size and has good precision The influence of the size of the specimen and the size of the discarded concrete block on the modulus of elasticity and the peak strain of regenerated mixed concrete is limited.
Using digital image correlation (Digital Image Correlation, referred to as DIC) compression failure process measurement technology of recycled concrete mixture was revealed, research shows that waste between concrete blocks and new concrete interface does not appear obvious agglomeration phenomenon of crack germination and expansion, the late development of cracks in concrete and concrete block through new waste the way the body.
Regeneration of quasi static test on mixed wall through 7 pieces of external steel sheet, analyzes the waste concrete replacement rate, plate thickness, axial compression ratio, diaphragm spacing, height to width ratio on the seismic performance of the specimen. Based on the new, combined strength of old concrete, the approximate calculation and Analysis on bearing capacity test the water level, compares the bearing capacity and the total amount of steel under the condition of the same level and reinforced concrete wall. The study shows that the waste concrete replacement rate changes on the initial stiffness of the specimen in 0 ~ 33%, the horizontal bearing capacity, failure displacement angle, energy dissipation capacity and seismic performance lag curve shape effect; external thin steel plate regeneration mixed wall design of axial compression ratio should not exceed 0.35; the thickness of the wall thickness of the steel plate and the ratio of up to 120 of the cases, the external wall is thin steel recycled mixture has stable hysteretic energy and deformation The ability to damage displacement angle to meet the needs of current seismic code; external wall with thin steel plate mixed recycled or slightly higher energy dissipation capacity and reinforced concrete wall is basically the same; the amount of steel in the general case, the external thin steel plate and reinforced concrete wall with mixed recycled base the considerable level of capacity.
Using ABAQUS software, a finite element model is established for the external wall of the thin steel plate mixed recycled, the effects of main parameters on the component level of force displacement curve, and compared with the experiment results. Comparing the calculation, considering the size effect of concrete compressive strength of recycled mixture combination. The research results show: monotonic loading when the external force level of thin steel plate regeneration mixed wall curve calculation of horizontal displacement ascent and reciprocating loading test skeleton curve of overall good agreement, but decreased with the test curve skeleton curve the difference; in the new, old concrete strength is less than 10MPa when the waste concrete replacement rate in 10% ~ 40% between the changes of the external thin the level of plate regeneration mixed wall less influence bearing capacity and initial stiffness; considering the amount of steel angle, simple thickened wall end boundary elements (tube) to improve The horizontal bearing capacity of the outer thin steel plate regenerative mixing wall may be more effective. Considering the two aspects of convenient construction of the waste concrete block and improving the horizontal bearing capacity of such members, it is suggested that the ratio of diaphragm spacing to wall thickness is 1 to 2.0. in practical engineering.

【学位授予单位】：华南理工大学
【学位级别】：博士
【学位授予年份】：2013
【分类号】：TU528;TU352.11

【引证文献】