亚麻纤维增强复合塑料加固钢筋混凝土梁的受弯性能研究

发布时间：2018-02-03 01:46

本文关键词： 亚麻纤维增强复合塑料加固抗弯性能剥离破坏　出处：《湖南大学》2015年硕士论文　论文类型：学位论文

【摘要】：纤维增强复合材料(Fiber Reinforced Polymer,FRP)因其轻质高强、便于施工、耐腐蚀等优点而开始受到土木工程领域的日益关注,开始以各类形式应用于工程结构当中。传统的人造纤维并不能在绿色和可持续方面有很好的表现。为满足环境需求,发展可再生材料,以自然纤维代替玻璃纤维等人造纤维作为复合材料的增强物用于工程,具有较好地前景。目前,自然纤维FRP的研究已经越来越受到各国的关注。本文以亚麻纤维代替人造纤维用于FRP基材,并通过试验深入研究了亚麻纤维增强复合塑料(FFRP,Flax Fiber Reinforced Polymer/Plastic)加固钢筋混凝土梁的抗弯性能,主要研究的内容如下:(1)本文对四种自然纤维(200g/m2半漂亚麻、300g/m2雨露亚麻、400g/m2雨露亚麻和黄麻)布和三种厚度(2层、4层和6层)FFRP试件进行了拉伸试验研究,发现300g/m2雨露亚麻布试件沿经向抗拉强度相对较高且伸长率适中,选择其制作成的FFRP试件拉伸性能较为稳定。通过试验得到了FFRP的拉伸强度、极限拉伸应变、拉伸模量和应力-应变曲线。(2)根据FFRP材性试验的结果和其他各材料的本构关系,对FFRP加固钢筋混凝土梁进行了抗弯性能分析,并推导出相应破坏模式下的承载力计算公式。(3)对6根FFRP加固钢筋混凝土梁以及2根普通钢筋混凝土对比梁进行了抗弯性能试验研究,研究了不同配筋率、不同纤维层数和不同预裂程度下FFRP加固梁的受力特性,对加固梁的荷载-挠度关系、钢筋的荷载-应变关系、增强材料的荷载-应变关系以及加固梁的延性进行了详细的分析。试验结果表明FFRP加固梁的荷载极限承载力与普通混凝土梁相比都有不同程度的提高,将加固梁极限承载力的试验值与理论值进行了比较,结果吻合较好。(4)考虑到本文进行抗弯性能试验的加固梁均未发生FFRP与混凝土间的界面剥离破坏,本文对3根粘贴了不同长度FFRP的加固梁进行试验,以分析FFRP与混凝土界面的粘结性能,试验发现FFRP粘贴长度最短的试验梁发生了剥离破坏,为保证FFRP与混凝土梁能够较好的协调工作并充分利用材料,建议将FFRP粘贴伸至梁支座处为宜。
[Abstract]:Fiber Reinforced Polymer (FRP) is easy to be constructed because of its light weight and high strength. Corrosion resistance and other advantages began to attract increasing attention in the field of civil engineering. The traditional man-made fiber is not good in green and sustainable aspects. In order to meet the environmental needs, renewable materials are developed. Using natural fibers instead of glass fibers as reinforcements of composite materials has a good prospect. The research of natural fiber FRP has been paid more and more attention in many countries. In this paper, flax fiber is used to replace man-made fiber for FRP substrate, and the flax fiber reinforced composite plastics is studied in this paper. The flexural behavior of reinforced concrete beams strengthened by Flax Fiber Reinforced Polymer / plastic. The main contents of this study are as follows: (1) in this paper, three hundred g / m ~ 2 rain and dew flax were studied for four kinds of natural fibers (200g / m ~ 2). Tensile tests were carried out on 400 g / m ~ 2 raindrops and jute) cloth and three kinds of FFRP specimens with two or four layers and six layers of FFRP. It was found that the tensile strength of 300g / m2 rain / dew linseed fabric was relatively high along the meridional direction and the elongation was moderate. The tensile strength and ultimate tensile strain of FFRP were obtained through the test. Tensile modulus and stress-strain curve. (2) according to the results of FFRP test and the constitutive relation of other materials, the flexural behavior of reinforced concrete beams strengthened by FFRP is analyzed. The calculation formula of bearing capacity under the corresponding failure mode is deduced. The flexural behavior of 6 reinforced concrete beams strengthened with FFRP and 2 normal reinforced concrete contrast beams are studied experimentally. The load-deflection relationship, load-strain relationship and load-strain relationship of FFRP strengthened beams were studied under different reinforcement ratios, fiber layers and pre-cracking degree. The load-strain relationship of reinforced materials and ductility of strengthened beams are analyzed in detail. The experimental results show that the ultimate load bearing capacity of FFRP strengthened beams is improved to some extent compared with ordinary concrete beams. The experimental value of ultimate bearing capacity of strengthened beam is compared with the theoretical value. The results are in good agreement with each other. (4) considering that none of the strengthened beams tested in this paper has the interface peeling failure between FFRP and concrete. In this paper, three strengthened beams with different length of FFRP are tested to analyze the bond behavior between FFRP and concrete interface. It is found that the test beam with the shortest FFRP length has been subjected to peeling failure. In order to ensure better coordination between FFRP and concrete beams and make full use of materials, it is suggested that FFRP should be pasted to the beam supports.
【学位授予单位】：湖南大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TU375.1

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