高温作用后GFRP筋与海水珊瑚混凝土粘结性能试验研究  

Experimental study on bond behavior of GFRP bar and seawater coral aggregate concrete after exposure to high temperatures

作　　者：周春恒 王君义 王新堂 陈宗平[3] ZHOU Chunheng;WANG Junyi;WANG Xintang;CHEN Zongping(School of Civil and Environmental Engineering,Ningbo University,Ningbo 315211,China;College of Science and Technology,Ningbo University,Ningbo 315211,China;College of Civil Engineering and Architecture,Guangxi University,Nanning 530004,China)

机构地区：[1]宁波大学土木与环境工程学院,宁波315211 [2]宁波大学科学技术学院,宁波315211 [3]广西大学土木建筑工程学院,南宁530004

出　　处：《复合材料学报》2023年第4期2224-2239,共16页Acta Materiae Compositae Sinica

基　　金：国家自然科学基金(52208174);浙江省自然科学基金(LQ20E080003);中央引导地方科技基金(桂科ZY21195010)。

摘　　要：为了研究高温后玻璃纤维增强树脂复合材料(GFRP)筋与海水珊瑚混凝土的残余粘结性能,对54个GFRP筋珊瑚混凝土试件及钢筋珊瑚混凝土对比试件进行了高温作用后的中心拔出试验,最高温度为350℃,混凝土强度等级考虑C20~C30。观察了高温后试件的表观变化及粘结破坏形态,获取了各试件的粘结-滑移曲线、粘结强度、粘结刚度和峰值滑移量,分析了不同温度、GFRP筋直径、海水珊瑚混凝土强度等因素对高温后GFRP筋与海水珊瑚混凝土粘结性能的影响。基于烧失率和XRD分析,剖析了GFRP筋海水珊瑚混凝土的高温劣化机制。最后,提出高温后GFRP筋与珊瑚混凝土的剩余粘结强度计算式和粘结-滑移本构模型。研究结果表明:高温作用后,尽管GFRP筋与珊瑚混凝土的粘结破坏形态与常温相似,GFRP筋的碳化和珊瑚混凝土的分解使得二者界面发生显著劣化;随着温度的提高,GFRP筋与珊瑚混凝土的粘结强度逐渐降低,峰值滑移量增大;GFRP筋直径越小,高温后的剩余粘结强度和剩余粘结刚度越小;珊瑚混凝土强度等级越高,剩余粘结刚度越大,峰值滑移量越小。所提出的高温后GFRP筋与珊瑚混凝土剩余粘结强度和粘结-滑移本构关系计算结果与试验结果均能较好吻合。To study the residual bond performance of glass fiber reinforced polymer(GFRP)bars and seawater coral aggregate concrete after exposure to high temperature,the pull-out tests were performed through 54 GFRP bars coral aggregate concrete specimens and steel bars coral aggregate concrete specimens.The highest temperature of 350℃and concrete classes of C20 to C30 were considered in this experiment.The surface changes and bond failure modes of specimens after high temperatures were observed.The bond stress-slippage curves,bond strength,stiffness and peak slippage were obtained.The influences of temperatures,bar diameters and concrete strengths on the bond properties of GFRP bars and coral aggregate concrete after high temperatures were analyzed.Furthermore,the deterioration mechanism of GRFP bars seawater coral aggregate concrete after high temperatures was revealed based on the analysis of mass loss rate and XRD tests.Finally,the bond stress-slippage constitutive rela-tion and residual bond strength of GFRP bars and coral aggregate concrete after high temperatures were proposed.The results show that even though the failure modes of specimens after high temperature are similar to those at room temperature,the interface of GFRP bar and coral aggregate concrete is degraded significantly due to the carbonization of GFRP bar and pyrolysis of coral aggregate concrete.The bond strength of specimens decreases and the peak slippage increases as the temperature increasing.The smaller the diameter of GFRP bars,the lower the residual bond strength and stiffness of specimens after high temperatures.The higher the strength classes of coral aggregate concrete,the greater the residual bond stiffness and the smaller the peak slippage.The calculated results of the proposed bond stress-slippage constitutive model and residual bond strength of GFRP bars-coral aggregate concrete after high temperatures show a good agreement with the experimental results.

关 键 词：GFRP筋 珊瑚混凝土 高温后 粘结强度 粘结-滑移本构模型 

分 类 号：TU528[建筑科学—建筑技术科学]