硫酸盐环境下粗糙度对CFRP-混凝土界面黏结应力试验研究
Study on Effect of Roughness on the Bearing Capacity of CFRP-concrete Interface under Sulfate Environment
关键词：
混凝土；CFRP；硫酸盐；界面；粗糙度；黏结强度
Key words：
Concrete; CFRP; Sulfate; Interface; Roughness; Bond strength
刊期：
２０19年第11期
DOI：
doi:10.19761/j.1000-4637.2019.11.043.06
文章编号：
基金项目：
国家自然科学基金项目（51278235）；辽宁省自然科学基金项目（20180551197）。
作者：
王宏军1， 殷雨时2
单位：
1.南京理工大学泰州科技学院，225300；2.大连海事大学土木工程系，116026
摘要
摘 要：为了考察硫酸盐环境下CFRP-混凝土界面黏结性能的退化规律，开展了162块CFRP-混凝土试件的单剪试验，研究了混凝土黏结面粗糙程度、混凝土强度等级、腐蚀龄期对CFRP-混凝土界面极限荷载、最大滑移量、黏结强度、断裂能的影响，并基于SEM扫描电镜技术分析了界面破坏机理。结果表明，混凝土强度从C30提升至C50，极限荷载上升幅度在1%～7%不等，总体上混凝土强度等级对提高界面黏结性能的影响不明显；硫酸盐环境下，环氧树脂胶体能较好的保护CFRP黏结区域；随着腐蚀龄期的增长，CFRP-混凝土界面的黏结性呈先增高后降低的趋势，增强点出现在第7 天，30 d后界面极限荷载呈高速下降趋势；界面能在7 d时达到最大，随后逐渐降低；硫酸钠晶体的膨胀劣化是影响CFRP-混凝土界面黏结性能的主要因素。
Abstract: In order to investigate the degradation law of the interface bonding performance of CFRP-concrete under sulfate environment, the single shear test of 162 pieces of CFRP-concrete specimens was carried out to study the effects of concrete bond surface roughness, concrete strength grade, erosion time on the ultimate load, maximum slip, bond strength and fracture energy of CFRP-concrete interface, and the interface failure mechanism based on SEM scanning electron microscope technology was analyzed. The results show that the concrete strength increases from C30 to C50, the increase range of ultimate load is from 1% to 7%, which indicates that the concrete strength has no obvious effect on the bond strength. Epoxy resin can well protect the CFRP bond area under sulfate environment. The bond strength of CFRP-concrete interface increases first and then decreases with the increase of corrosion age, and the bond performance enhances on the 7th day, 30 days later, the ultimate load decreases rapidly. Interfacial fracture energy reached maximum on 7th day, and then gradually decreased. The expansion deterioration of sodium sulfate crystal is the main factor affecting the interfacial bonding performance of CFRP-concrete.
结论
（1）硫酸盐环境下，环氧树脂胶体能较好的保护混凝土黏结区域，7 d内黏结区域混凝土上表层损伤可近似忽略不计。
（2）硫酸盐环境对CFRP-混凝土界面的黏结性呈现先增高后降低的趋势。增强点均出现在第7 d，30 d后界面极限荷载降落严重，呈现高速率下降趋势。CFRP-混凝土界面能呈现先升高后降低的趋势。腐蚀7 d时，界面能达到最大，随后逐渐降低。
（3）相对于高强混凝土，低强度混凝土与CFRP布的黏结性能受混凝土表面粗糙度影响较大。
（4）混凝土材料在30 d内生成的Na2SO4晶体是导致混凝土开裂的主要原因，60 d后，Na2SO4晶体联系成大块晶体，损伤加速，力学性能降低明显。
（5）在混凝土加固工程中，采用最佳混凝土表面粗糙程度，有利于增大混凝土黏结面-CFRP界面间黏结应力，单一提高混凝土强度等级来提高界面黏结性能的作用很小。
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引用本文
王宏军,殷雨时.硫酸盐环境下粗糙度对CFRP-混凝土界面黏结应力试验研究[J].混凝土与水泥制品,2019(11):43-48.
WANG H J,YIN Y S.Study on Effect of Roughness on the Bearing Capacity of CFRP-concreteInterface under Sulfate Environment[J].China Concrete and Cement Products,2019(11):43-48.
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