预应力高性能再生混凝土桥梁的受弯性能及设计理论研究

The structure diversification and the working environment complication of prestressed concrete bridge in modern communication engineering, cause the increasing of bridge structure complexity and durability requirement. That using industry waste as recycled coarse aggregate and fly ash make high-performance recycled aggregate concrete (HPRAC) is beneficial to conserve energy, reduce garbage emission and save construction costs. The high-performance recycled aggregate concrete being applied into prestressed concrete bridge can not only solve the problem of concrete pouring, but also increase service life of bridge. This project will conduct experimental investigation, theoretical study and numerical calculation on the flexural behavior and design theory of prestressed high-performance recycled aggregate concrete. The flexural performance of prestressed concrete beam on short-time loading and long-time loading will be investigated. The main influencing factors of flexural performance will be discussed. According to the experimental test on short-time loading, the calculation formula of cracking load and bending capacity will be established, and the equations of stiffness and maximum crack width on short-time loading will be given. According to the experimental test on long-time loading, the enlargement coefficient of stiffness and maximum crack width on long-time loading will be founded. In addition, finite element methods will be adopted to perfect the theoretical formulas. The research of this project will set a guideline for high-performance recycled aggregate concrete to the practice of prestressed concrete bridge engineering.

现代预应力混凝土桥梁的结构多样化和工作环境复杂化，导致了桥梁结构构造复杂和耐久性要求提高。本项目利用再生粗骨料和粉煤灰等工业废料制备的高性能再生混凝土浇筑预应力混凝土桥梁，具有节能减排、降低建筑成本的特点，不仅可以解决桥梁的浇筑问题，还可以提高桥梁的服役寿命。本项目采用试验研究、理论分析和数值计算相结合的研究方法，首先，对短期荷载和长期荷载作用下的预应力高性能再生混凝土梁的受弯性能开展试验研究，探讨影响桥梁短期与长期受弯性能的主要因素，建立开裂荷载与受弯承载力计算公式、短期荷载和长期荷载下的刚度与最大裂缝宽度的计算公式；最后，利用有限元手段对梁的短期与长期受弯性能进行数值模拟，完善理论计算模型。本项目的研究工作将对高性能再生混凝土在预应力混凝土桥梁中的工程应用具有指导意义。

以再生粗骨料、粉煤灰等工业废料制成的高性能再生混凝土是一种具有自密实性的环保型混凝土，在桥梁结构中有着广阔的发展前景。本项目以自密实再生混凝土在预应力混凝土桥梁结构中的应用为目的，开展了以下工作：（1）带肋钢筋试件的粘结滑移试验研究，建立了带肋钢筋与自密实再生混凝土之间的粘结滑移本构关系模型；（2）自密实再生混凝土梁弯、剪试验研究，对开裂荷载、极限荷载等试验值与各国混凝土规范理论值进行比较，探讨规范对自密实再生混凝土梁的适用性；（3）预应力自密实再生混凝土梁的受弯试验研究，比较与预应力普通混凝土梁荷载-挠度曲线的区别，探讨各国规范对预应力自密实再生混凝土梁开裂荷载与极限荷载的适用性，并提出改善预应力自密实再生混凝土梁变形过大的构造措施；（4）预应力自密实再生混凝土梁的长期性能试验研究，分析影响长期徐变的原因，给出预应力自密实再生混凝土梁的徐变系数建议值，分析长期荷载对预应力自密实再生混凝土梁受弯性能的影响；（5）约束自密实再生混凝土的轴压试验研究，建立了约束自密实再生混凝土的本构模型。本项目的研究成果可为自密实再生混凝土在预应力混凝土桥梁上的应用提供了理论依据。