碳纳米管改善面板混凝土早龄期变形研究

Study on the improvement of early age deformation offace slab concrete by carbon nanotubes

在水利工程中大体积混凝土开裂问题普遍存在,而早龄期变形是大体积混凝土早龄期开裂的主要驱动力。为了研究碳纳米管(CNTs)对面板混凝土(FSC)早龄期变形的影响,采用温度—应力试验,研究两种温度养护历程下基准面板混凝土和掺入CNTs面板混凝土的应力与应变发展规律。基于成熟度理论,分离出早龄期温度变形与徐变,得到FSC早龄期时变热膨胀系数与徐变度发展曲线。试验结果表明:相较于基准组,CNTs的掺入可以减少FSC早龄期自收缩,降低早龄期热膨胀系数,从而减少温度变形,增加早龄期拉伸徐变度,可以有效改善FSC早龄期变形,降低FSC早龄期开裂风险。

In hydraulic engineering,cracking of mass concrete is a common problem,and early age deformation is the main driving force for early age cracking of mass concrete.In order to study the influence of carbon nanotubes(CNTs)on the early age deformation of face slab concrete(FSC),a temperature stress test is used to study the stress and strain development in the benchmark face slab concrete and the face slab concrete mixed with CNTs under two temperature curing processes.Based on maturity theory,the temperature deformation and creep at early ages are separated,and the time varying thermal expansion coefficient and the creep development curve at early ages of FSC are obtained.The experimental results show that compared with the reference group,the incorporation of CNTs can reduce the self shrinkage of FSC,reduce the thermal expansion coefficient and the temperature deformation,increase the tensile creep,effectively improve the deformation,and reduce the cracking risk of FSC at early ages.