Wang Ce, Guan Shuai, Sabbrojjaman Md, Tafsirojjaman T
CCCC Highway Consultants Co., Ltd., No. 33, Dongsiqiancaomian Alley 33, Dongcheng District, Beijing 100010, China.
The Key Laboratory of Urban Security and Disaster Engineering of Ministry of Education, Beijing University of Technology, Pingleyuan Road 100, Beijing 100124, China.
Polymers (Basel). 2023 Jun 30;15(13):2906. doi: 10.3390/polym15132906.
Prestressed concrete structures have witnessed widespread use in building and infrastructure applications during the last two decades due to their high stiffness and strength indices. However, structural failures caused by the corrosion of steel reinforcing bars or strands have proliferated, opening the door for carbon fibre-reinforced polymer (CFRP) strands as an excellent alternative with high corrosion resistance. The bonding interaction between the CFRP strands and concrete is the fundamental parameter in shaping the structural behaviour of CFRP prestressed concrete structures. In this paper, the bonding behaviour between CFRP strands and concrete with grouting admixture is experimentally investigated based on three groups of standard pull-out tests. The bond strength of CFRP strands was systematically studied and compared against steel strands. The untreated CFRP strands exhibited an inefficient bonding strength with the grouting admixture, equivalent to only 5% compared to steel strands of the same diameter. Surface coating with epoxy quartz sand can significantly improve the anchoring efficiency of CFRP strands up to 14 times compared to the untreated strands, which is approximately as efficient as steel strands. Moreover, the bond-slip curves between CFRP strands and concrete were analysed and were found to be different compared to steel strands. Finally, this study proposed bond-slip constitutive models of CFRP strands with better applicability, using an exponentially damped sine function to fit the residual segment of the curve.
在过去二十年中，预应力混凝土结构因其高刚度和强度指标而在建筑和基础设施应用中得到广泛使用。然而，由钢筋或钢绞线腐蚀引起的结构失效日益增多，这为碳纤维增强聚合物（CFRP）绞线成为具有高耐腐蚀性的优良替代品打开了大门。CFRP绞线与混凝土之间的粘结相互作用是塑造CFRP预应力混凝土结构结构性能的基本参数。本文基于三组标准拉拔试验，对CFRP绞线与掺有灌浆外加剂的混凝土之间的粘结性能进行了试验研究。系统研究了CFRP绞线的粘结强度，并与钢绞线进行了比较。未经处理的CFRP绞线与灌浆外加剂的粘结强度较低，仅相当于相同直径钢绞线的5%。与未经处理的绞线相比，环氧石英砂表面涂层可将CFRP绞线的锚固效率显著提高14倍，其效率与钢绞线大致相当。此外，分析了CFRP绞线与混凝土之间的粘结-滑移曲线，发现其与钢绞线不同。最后，本研究提出了适用性更好的CFRP绞线粘结-滑移本构模型，采用指数衰减正弦函数拟合曲线的残余段。
