钢—连续纤维复合筋增强海砂混凝土梁基本性能研究

发布时间：2018-04-03 14:13

本文选题：钢-连续纤维复合筋(SFCB)　切入点：海砂混凝土　出处：《东南大学》2015年硕士论文

【摘要】：随着国家的沿海开发岛礁建设,河砂在一定地区出现了短缺的现象,于是海砂代替河砂作为混凝土细骨料,正在越来越多地被运用在工程建设之中。但海砂中的氯盐会造成混凝土中钢筋的严重锈蚀,降低结构的耐久性。而钢-连续纤维复合筋(SFCB)因其优越的耐腐蚀性能及良好的刚度为海砂混凝土的应用提供了新的方法。本文以梁为研究对象对SFCB增强海砂混凝土结构进行了研究。SFCB与海砂混凝土良好的界面粘结性能是两者协同工作的基础,故本文首先通过试验研究了SFCB与海砂混凝土的粘结性能。试验共设计制作并测试了66个拉拔试件,用以获得SFCB和钢筋分别与海砂、河砂混凝土间的短期与长期粘结性能。试验配置了5%NaCl溶液来模拟海水,并通过两种不同的腐蚀方式进行研究：20℃海水干湿循环和40℃海水浸泡。研究相应环境腐蚀后试件的粘结-滑移曲线,并分析曲线各阶段的特点、受力过程、粘结破坏机理,以及筋材经腐蚀后与混凝土的极限粘结强度随腐蚀龄期的变化。之后,本文通过试验研究了SFCB增强海砂混凝土梁的抗弯性能。试验设计共制作并测试了8根海砂混凝土梁,研究SFCB增强海砂混凝土梁的短期受弯性能以及在盐溶液干湿循环作用下SFCB增强海砂混凝土梁的长期受弯性能,并与同等条件下的钢筋海砂混凝土梁进行对比,从承载能力、二次刚度、裂缝发展、延性等角度研究分析海洋环境下SFCB增强海砂混凝土梁的长期退化规律。通过SFCB与海砂混凝土粘结性能试验,获得如下结论：SFCB与海砂混凝土具有良好的短期粘结性能；常温干湿循环下,SFCB与海砂混凝土有着良好的长期粘结性能,且优于其与河砂混凝土的粘结性能；高温海水浸泡下,SFCB与海砂混凝土间的粘结性能退化较快,过高的温度将严重影响SFCB的耐久性；钢筋与河砂混凝土的粘结强度随着腐蚀龄期增加,而钢筋与海砂混凝土的粘结强度由于钢筋的严重锈蚀而有下降趋势。通过SFCB增强海砂混凝土梁抗弯性能试验,可以发现：海砂混凝土梁的力学性能与河砂混凝土梁相似,SFCB增强海砂混凝土梁具有良好的短期力学性能,并具有明显而稳定的二次刚度；经过长期腐蚀后的钢筋海砂混凝土梁锈蚀状况较为严重,其屈服后刚度的退化速度随着腐蚀龄期的延长而有所增加,延性随着腐蚀龄期的增长有下降的趋势,但极限强度暂未受到明显影响；经过长期腐蚀后的SFCB梁内SFCB表面无明显腐蚀痕迹,但屈服后的二次刚度随腐蚀龄期延长有所降低,极限强度略有下降：经过长期腐蚀之后,钢筋梁的裂缝开展更加稀疏,裂缝宽度较对比梁有着很大的增长,而SFCB梁的主裂缝下部则出现较多分支,裂缝间距进一步减小,裂缝宽度的增长幅度较小。本文结合粘结性能试验数据通过TSF法对SFCB与海砂混凝土间的粘结性能进行了寿命预测,并据此提出了海砂混凝土中SFCB的基本锚固长度。本文还提出了SFCB增强海砂混凝土梁正截面承载能力与裂缝宽度的计算公式,根据公式计算出的结果与试验实测值吻合较好。
[Abstract]:Along with the national coastal reef construction, river sand shortage phenomenon in a certain area, so the sand instead of river sand as fine aggregate concrete is more and more used in engineering construction. But the serious rust chloride in sea sand will cause corrosion of steel in concrete, reduce the durability of structure and steel. Continuous fiber composite bar (SFCB) because of its excellent corrosion resistance and good stiffness for sea sand concrete application provides a new method. Based on the beam as the research object of SFCB reinforced concrete structure of the sand interface bonding properties of.SFCB and the sea sand concrete foundation is the two work together, so firstly, through the tests of bond behavior between SFCB sea sand concrete. Tests were designed and 66 pull-out specimens were tested to obtain SFCB and reinforced with sand, river sand concrete room The short-term and long-term bond performance test. The configuration of the 5%NaCl solution to simulated seawater, and conducted the research through two different ways: 20 degrees of seawater corrosion of wet and dry cycles and 40 DEG C seawater immersion. Specimens of bond slip curves of the corresponding environmental corrosion, and analyze the characteristics of each stage of the curve, the process of stress, bond the failure mechanism, the ultimate bond strength and reinforcement after corrosion and concrete change with age. After corrosion, the experiment was conducted to study the flexural performance of SFCB reinforced concrete beams. The sand test design were fabricated and tested 8 sand concrete beams, sand concrete beams short-term flexural properties and in salt solution under wet and dry cycle SFCB enhanced sand concrete beam flexural performance of long-term enhanced on SFCB, compared with reinforced concrete beams and sand under the same conditions, the carrying capacity of the two stiffness, crack The development of research, such as analysis of ductility of SFCB in ocean environment to enhance the long-term degradation of sea sand concrete beams. The bond behavior between SFCB sea sand concrete test, the conclusion was as follows: SFCB and sea sand concrete has short-term good adhesion; room temperature wet dry cycle, SFCB and sea sand concrete has a long-term bond with good performance, and better than the with river sand concrete bonding performance; high temperature seawater immersion, binding property of SFCB and the rapid degradation of sea sand concrete, the high temperature will seriously affect the durability of the SFCB; and the bond strength of reinforced sand concrete corrosion with age increasing, and the bond strength between steel bar and concrete sand due to the severe corrosion of steel but there is a downward trend. Through enhanced SFCB test, sea sand concrete beams strengyhened can be found: the mechanical properties of concrete beams and sand sand concrete beams Similar to that of SFCB reinforced concrete beams with sand short-term good mechanical properties, and has obvious and stable two stiffness; reinforced concrete beams after sand corrosion after long-term corrosion is more serious, the post yield stiffness degradation rate increased with age and increased corrosion, corrosion with ductility age there is a downward trend, but the ultimate strength are significantly affected by SFCB; beam after corrosion of SFCB surface without obvious signs of corrosion, but the yield after two times of stiffness with corrosion age decreased, ultimate strength decreased slightly after long-term corrosion, the cracks of the reinforced beam to carry out more sparse, crack width compared with the control beam has a great growth, while the main crack lower SFCB beam appeared more branches, the crack spacing is further reduced, the growth rate of crack width. This paper combined adhesive Can the test data by the method of TSF and SFCB on adhesive properties of sea sand concrete of the life prediction, and the basic anchorage length of SFCB in sea sand concrete is put forward. This paper also put forward the SFCB enhanced the calculating formula of bearing capacity and crack width of cross section of sea sand concrete beams, are in good agreement with the calculated results and test results according to the formula value.

【学位授予单位】：东南大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TU528

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