碳纳米管/碳纤维对混凝土静力特性的影响及微观机理分析

Influence of CNTs/CF on the static characteristics of concrete and analysis of its micro-mechanism

提高混凝土材料的力学性能已经成为防灾减灾工程及防护工程领域关注的热点问题。通过在混凝土基体中掺入占水泥质量比为0%(素混凝土)、0.1%、0.2%、0.3%和0.4%的碳纳米管,以及体积分数为0.1%、0.2%、0.3%和0.4%的碳纤维,分别开展不同碳纳米管、碳纤维掺量条件下混凝土的静态力学实验,并结合压汞实验从微观角度分析碳纳米管和碳纤维对混凝土静力特性的影响机理。结果表明:随着碳纳米管、碳纤维掺量的逐渐增大,碳纳米管混凝土的抗折强度表现出增强的趋势,而其抗压强度则表现出先增强后减弱的趋势;碳纤维混凝土的抗压强度和抗折强度均呈现出先增强后减弱的趋势。碳纳米管混凝土的大孔减少而过渡孔增加,与之相反,碳纤维混凝土大孔增加而过渡孔减少。

To improve the mechanical properties of concrete materials has become a hot issue in disaster prevention and reduction engineering and protective engineering.Concrete was mixed with carbon nanotubes(CNTs)with a cement mass ratio of 0%(plain concrete),0.1%,0.2%,0.3%and 0.4%,and with the volume fractions of 0.1%,0.2%,0.3%and 0.4%carbon fiber(CF),respectively.The static mechanical tests of concrete with different CNTs and CF content were carried out,and the mercury intrusion test was combined to clarify the influence mechanism of CNTs and CF on the static properties of concrete from microscopic point of view.The results showed that with the gradual increase in the content of CNTs and CF,the flexural strength of CNTs reinforced concrete showed increasing trend,and its compressive strength showed a trend of first increasing and then weakening.The compressive strength and flexural strength of CF reinforced concrete showed a trend of first increasing and then weakening.The large pores of CNTs reinforced concrete decreased and the transition pores increased.On the contrary,the large pores of CF reinforced concrete increased and the transition pores decreased.