【作者】 靳祖光；

【导师】 刘铁军； 李伟文；

【作者基本信息】 哈尔滨工业大学 ， 土木工程， 2010， 硕士

【摘要】 近年来纤维增强复合材料(Fiber Reinforced Plastics,简称FRP)筋开始在桥梁、公路、隧道等方面开始得到应用,并且凭借其高强度、轻质、耐腐蚀、抗疲劳、电磁绝缘性等优良的性能,成为有可能替代钢筋在结构中应用的比较有前景的新型材料。其中,由于玻璃纤维增强复合材料(GFRP)筋优良的性能和低廉的成本,在国内外得到了广泛的研究和应用。但是由于FRP筋在实践中应用年限较短,缺乏足够的数据和资料,从而限制了该新型材料进一步的推广和应用,因此GFRP筋的耐久性能,特别是恶劣环境下GFRP筋的力学和劣化机制等问题的研究颇受关注。研究表明,GFRP筋容易经受湿热、碱环境等因素的侵蚀从而导致力学性能的劣化,因此本文考虑采用有机蒙脱土改性聚合物基体来制备Nano-GFRP筋,从而有效提高聚合物保护层的抗腐蚀能力,改善材料的耐久性能。本文的研究内容主要包括以下几部分:(1)根据原位插层聚合法,制备出不饱和聚酯/有机蒙脱土(UP/OMMT)纳米复合材料。试验结果表明:蒙脱土的加入会阻碍凝胶和固化过程,通过X-射线衍射分析(XRD)、透射电子显微镜(TEM)等微观表征技术证明制备的纳米复合材料为插层型,同时蒙脱土的加入会提高材料的热稳定性能,并具有增强增韧作用;(2)通过对纯树脂材料和3wt%纳米复合材料的阻隔性能的研究结果表明:在水溶液浸泡和水汽吸收试验中,纳米复合材料的扩散系数都要低于纯树脂材料,并且都呈现出了一定的非Fick性,同时稳态扩散试验中纳米复合材料扩散系数和吸湿率降低了74%;(3)在工厂环境下制备出普通GFRP筋和3wt%蒙脱土含量的Nano-GFRP筋,通过拉伸试验结果表明,由于制备工艺过程导致了聚合物内部团聚和微裂缝的增多,Nano-GFRP筋的抗拉强度降低。采用加速老化试验方法,通过水溶液的浸泡和干湿循环试验表明,Nano-GFRP筋的劣化速度要低于普通GFRP筋,同时由于材料内部的进一步固化,会导致劣化过程中Nano-GFRP筋强度和弹模的波动变化。更多还原

【Abstract】 Rencently, Fiber Reinforced Plastics(FRP) reinforcement is gaining more popularity in construction in bridges, roads and tunnels. Due to their superior properties, such as high mechanical properties, light-weight, cossorion resistance, FRP bar become one of new alternative materials as a replacement for traditional steel bars. GFRP reinforcement attracted research interest worldwide because of their superior properties and low cost. The lack of data on durability of FRP reinforcements is a major obstacle to their acceptacen on a broader scale in civil engineering. The durability of GFRP reinforcement, especially under sever environmental conditions, is now recognized as the most critical topic of research.It is proved that GFRP bars were subjected to hygrothermal effect and alkaline attack, so we introduced organoclay into polymer matrx to fabricate Nano-GFRP bars aiming at improvement of the durability. The detail works listed as follows:(1) In-situ polymerization method was employed to fabricate unsaturated polyester/organo-montmorillonite(UP/OMMT) nanocomposite. Results showed that introduced OMMT delayed the gelatin and curing. According to characterization of XRD and TEM, the intercalated structure was obtained. At the same time, the thermal stability, strength and ductility performance of nanocomposite were also improved;(2) Compared to neat UP, the barrier performance of 3wt% nanocomposite was improved. Results indicated that in water immersion and absorption tests, the diffusion coefficient was lower than neat UP, and both diffusion process deviated from the Fickian diffusion. In the vapor stable diffusion test, both diffusion coefficient and weight-gain were reduced by 74%.(3) Common GFRP bars and 3wt% GFRP bars were fabricated in the factory condition. The tensile tests results showed that the preparation would lead to more organoclay aggregations and micro-cracks, which lowered tensile strength of Nano-GFRP bars. According to accelerated aging method, both water immersioin and dry/wet cycles tests were employed. The results indicated that the degradation speed of Nano-GFRP bars was reduced, and because of further curing inside, the strength and modulus of Nano-GFRP bars would fluctuated during aging periods.更多还原