【作者】 张；

【导师】 刘立新；

【作者基本信息】 郑州大学 ， 结构工程， 2014， 博士

【摘要】 我国仍处于大规模的基本建设时期,新建工程和拆除旧有建筑产生了大量建筑垃圾,目前对建筑垃圾的处置方式主要是填埋与堆放,资源化再利用的比率很低,建筑垃圾大量填埋与堆放不仅侵占破坏土地,还严重污染环境。我国城乡大量的旧建筑物以砌体结构或混合结构为主,建筑垃圾中废砖所占的比例很大,但当前对废砖再生利用的研究较少。本文针对急待解决的大量废砖建筑垃圾的再生利用问题,开展建筑垃圾废砖再生粗骨料混凝土及预制墙板受力性能研究,力求将大量废砖建筑垃圾开发为一种新型墙体材料。论文的研究内容对促进建筑垃圾的综合利用,节约资源、保护环境具有重要意义,研究成果可供废砖再生粗骨料混凝土预制墙板的工程应用参考,对其他建筑垃圾的再生利用也有借鉴作用。论文研究工作得到了河南省新型墙材改革基金的资助。论文在对废砖再生粗骨料和建筑垃圾再生细骨料的物理力学性能、废砖再生混凝土的配合比和物理力学性能试验研究的基础上,采用大粒径废砖再生粗骨料、废混凝土再生细骨料制作了再生混凝土预制墙板,进行了这种新型墙板在竖向荷载、平面外荷载和水平低周往复荷载作用下的受力性能试验,并进行了数值分析。根据研究结果并参考国内外有关资料,提出了工程应用的建议。论文的主要工作和成果有：1.采用废弃粘土砖经轻微破碎获得大粒径粗骨料,对废砖再生粗骨料和废混凝土再生细骨料的颗粒级配、表观密度、堆积密度、空隙率、吸水率、压碎指标等物理力学性能进行了较为系统的试验和分析,并与天然骨料进行比较。结果表明建筑垃圾废砖再生粗骨料强度较低,不适用于配制对强度要求较高的普通混凝土,但可用于配制对强度要求不高的墙板类构件或其他墙体材料的混凝土；废混凝土再生细骨料除吸水率较大外其他性能与天然砂相近,采取一定措施后可替代天然砂配制混凝土。2.采用100%大粒径废砖再生粗骨料和100%废混凝土再生细骨料配置再生混凝土,根据废砖再生粗骨料吸水率大、吸水速度快的特点,采用预先添加附加水、二次搅拌的方法获得拌合物具有较好工作性能、强度等级可达到C10-C20的废砖再生混凝土；根据试验结果,给出了立方体抗压强度随净水胶比变化的关系式。对废砖再生粗骨料混凝土的抗压强度、弹性模量以及收缩变形、碳化等物理力学性能进行了试验研究,提出了废砖再生粗骨料混凝土弹性模量计算公式和力学性能建议指标,为墙板计算分析和工程应用提供了参考依据。3.制作了边缘构件为普通混凝土、芯部为大粒径废砖再生粗骨料混凝土组成的预制墙板,进行墙板在竖向荷载和平面外荷载作用下的受力性能试验和分析。结果表明在平面内竖向荷载作用下,边缘构件的普通混凝土和墙板芯部的废砖再生粗骨料混凝土能共同受力,二种混凝土的强度均能较好发挥,建立了废砖再生粗骨料混凝土预制墙板轴向受压承载力的计算公式,公式的计算结果有较大安全储备并可保证墙板在正常使用极限状态下不出现裂缝；在大于可能承受的最大风荷载的平面外均布荷载作用下,墙板侧向挠度很小且未产生裂缝,在保证上、下两端可靠连接的基础上可不进行专门的抗风验算；基于弹性薄板理论和弹性支承边界条件,推导出废砖再生粗骨料混凝土预制墙板在平面外均布荷载作用下的位移、内力、应力和应变等的计算公式,为墙板在平面外荷载作用下的受力分析提供了有效方法。4.进行了废砖再生粗骨料混凝土预制墙板在给定轴压比下的水平低周往复加载试验,对墙板开裂前后的滞回曲线、骨架曲线、刚度退化曲线、耗能和恢复性能、以及破坏特点等进行了分析。结果表明废砖再生混凝土预制墙板开裂前刚度退化不明显,水平荷载稳定；开裂后的耗能和变形能力均较好。参照深受弯构件受剪承载力的计算方法,建立了考虑边柱普通混凝土作用的废砖再生混凝土预制墙板的受剪承载力计算公式,公式计算值与试验结果符合较好,可供废砖再生混凝土预制墙板工程设计参考。5.引入废砖再生粗骨料混凝土材料性能试验结果,运用有限元软件ABAQUS建立再生粗骨料混凝土墙板的分析模型,对废砖再生粗骨料混凝土预制墙板在低周往复荷载作用下的受力性能进行了数值分析并与试验结果比较。结果表明在各次荷载循环下数值分析的应力状态、滞回曲线、骨架曲线、耗能曲线、刚度退化曲线以及残余变形均与试验实测结果接近;考虑废砖再生粗骨料混凝土材料性能的有限元分析,可作为对废砖再生粗骨料混凝土预制墙板受力性能分析的一种有效方法。6.根据试验研究成果并参考国内外相关资料,提出了包括废砖再生粗骨料混凝土预制墙板的制作、用于多层房屋承重墙体和框架结构房屋外墙及隔墙的设计施工要点等内容的工程应用初步建议。结合我国建筑垃圾再生利用的现状和存在的问题,提出了推广废砖再生混凝土预制墙板以及建筑垃圾处理和再生利用产业化的建议。更多还原

【Abstract】 China is still in the period of large-scale capital construction, new construction and demolition of old buildings have generated a lot of construction waste. However, most of the construction waste is transported directly to the countryside or city perimeter with simple landfill or open-air piling up without any treatment, which not only wastes arable land and natural resources, but also pollutes the environment. In China, a lot of old buildings in urban and rural areas is masonry structures or hybrid structure, and waste clay brick account for a large percentage in all construction waste, on which few studies have been carried out.This paper aimed at the urgent problem of waste brick recycling, carry out the research on recycled waste clay brick coarse aggregate concrete and mechanical performance of recycled precasted wall slab, strive to develop a new type of wall materials with waste clay brick. Research content of this paper is important for the promotion of construction waste utilization, resource conservation and environment protection. The research result can provide engineering application reference of recycled waste clay brick coarse aggregate concrete precasted wall slab. This work was funded by the New Wall Materials Reform Fund of Henan Province.On the basis of test research on physical and mechanical properties of recycled wasted clay brick coarse aggregate and recycled construction waste fine aggregate, mixture test research on recycled waste clay brick concrete is carried out. The recycled concrete precasted wall slab is made of large size recycled wasted clay brick coarse aggregate and recycled construction waste fine aggregate. Mechanical performance experiment and numerical analysis of such new wall slab under vertical load, out-of-plane load and low cyclic loads with given axial compression ratio is carried out. Proposal for engineering applications is put forward according to the research result and relevant reference. The main work and research result of the paper is as follows.1. Systematic testing and analysis on physical and mechanical properties such as particle size distribution, apparent density, bulk density, porosity, water absorption and crushed indicators of crushed large size waste clay brick coarse aggregate and crushed concrete fine aggregate is carried out and compared with the natural aggregate. Test result show that recycled waste brick coarse aggregate is characterized with low strength and only suitable for the wall slab members and others that have a low demand on strength. Except has a higher water absorption, recycled waste concrete fine aggregate is similar to natural sands and can be used instead of natural sands in concrete mixture after certain treatment.2. Recycled concrete mixture were designed with 100% recycled large size waste clay brick coarse aggregate and 100% recycled waste concrete fine aggregate. According to the high water absorption characteristic of recycled waste clay brick coarse aggregate, methods as additional water added in advance and two-stage mixing procedure is employed to improve the working performance of concrete mixture. The strength level of recycled concrete can reach C10-C20. Based on the experiments result, relationship between cubic strength and net water to blinder ratio was obtained.Test research on compressive strength, elastic modulus, shrinkage deformation, carbonation performance and etc. of recycled waste clay brick coarse aggregate concrete is carried out. The formula of modulus elasticity and recommended indicators of mechanical properties is proposed, which provide reference for wall slab analysis and engineering application.3. Precasted wall slab with normal concrete as edge member and large size recycled wasted clay brick coarse concrete as the core part is made, and experiment research of wall slab under vertical load and out-of-plane load is carried out.Test result shows that under vertical in-plane load, normal concrete of edge member can together with the core recycled concrete, and both can exert strength better. Design equation was advised for the recycled wall slab under in-plane vertical load, which have a large safety reserves and assure no crack appeared under normal service limit state. Under uniform out-of-plane load that higher than wind load, lateral deflection is very small and no crack appeared.Based on elastic thin plate theory and elastic support boundary conditions, the equation for displacement, internal force, stress and strain of recycled wall slab under uniform out-of-plane load Is derived, which provide effective methods for stress analysis of wall slab under out-of-plane load.4. Mechanical performance experiment of recycled concrete precasted wall slab under low cyclic loads with given axial compression ratio is carried out. The energy dissipation, deformation capacity, hysteretic behavior, ductility and rigidity degeneration and failure mechanism of recycled concrete precasted wall slab before and after cracks appeared were analyzed.Test result shows that the stiffness degradation of recycled concrete precasted wall slab before cracking is not obvious and horizontal loads keep stable. The energy dissipation and deformation capacity of recycled concrete precasted wall slab is better after cracking.Refered to the shear bearing capacity calculation method of deep flexural members, the shear bearing capacity formula of recycled concrete precastesd wall slab that consider the effect of edge column concrete is established. According to the formula, the calculation result fitted well with test results and thus can be refered by engineering design.5. According to materials properties test result of recycled waste clay brick coarse aggregate concrete, finite element software ABAQUS is used to establish the analysis model of recycled concrete precasted wall slab. Numerical analyis on mechanical performance of recycled concrete precasted wall slab under low cyclic loads is carried out and comparied with the experiment result.The comparision result shows that the stress state, energy dissipation, deformation capacity, hysteretic behavior, skeleton curve, ductility and rigidity degeneration and residus deformation by numerical analysis under each load cycle is very closer to the experiment result. The finite element analysis considering materials properties of recycled waste clay brick coarse aggregate concrete may be a efficient method to analysis the mechanical performance of recycled waste clay brick coarse aggregate concrete precasted wall slab.6. According to experiment research result and relevant reference, the preliminary proposals of recycled concrete precasted wall slab applied on storey bearing wall and frame building facades and wall, including production of recycled concrete precasted wall slab, main points of design and constrcution is suggested.Combined with the status and problems of China’s recycling of construction waste, proposals to promote the industrialization of waste disposal and engineering application of recycled concrete precasted wall slab is presented.更多还原