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无机增殖剂对PE/ECC力学、抗氯离子渗透及自愈合性能的影响

Effect of capillary crystalline cement additive on the mechanical, anti-chloride ion permeability, and self-healing properties of PE/ECC

    摘要
  • 摘要: 为研究无机增殖剂(CCCA)对聚乙烯(PE)纤维增强高延性水泥基复合材料(ECC)力学、抗氯离子渗透及自愈合性能的影响，以PE/ECC为对照组，分别掺入不同质量分数的CCCA (2wt%、4wt%、6wt%、8wt%、10wt%)，通过抗压、抗折、抗拉、电通量法及预加应变损伤法对PE/ECC力学、抗氯离子渗透及自愈合性能进行研究，并利用XRD、SEM-EDS对其自愈合产物进行物相成分、微观形貌及元素组成分析。结果表明：随着CCCA掺量的增加，PE/ECC力学和抗氯离子渗透性能呈先增后减趋势，当CCCA掺量为4wt%时，CCCA对PE/ECC力学和抗氯离子渗透性能整体提升最为明显，抗压、抗折、极限抗拉强度分别提升了55.5%、10.8%、79.4%，极限拉应变变化不大，电通量下降了38.6%。自愈合试验表明，掺入CCCA后，PE/ECC抗拉强度和应变能的恢复率有明显提升，自愈合性能得到了增强。当预损伤应变为0.5%时，掺CCCA的PE/ECC试件抗拉强度和应变能在养护84天后均高于原始基体，较原始基体分别提高10.41%和2.83%。未掺CCCA的PE/ECC试件在3种应变损伤下的抗拉强度和应变能均低于原始基体。XRD和SEM-EDS结果显示，掺CCCA的PE/ECC水化产物中CaCO3、水化硅酸钙(C-S-H)、钙矾石(AFt)衍射峰值强度有所增长，自愈合产物主要是C-S-H晶体，且掺CCCA的PE/ECC中分布更密集。

     

    Abstract: To study the effects of capillary crystalline cement additive (CCCA) on the mechanical, chloride ion penetration resistance and self-healing properties of polyethylene (PE) fiber reinforced engineered cementitious composites (ECC), PE/ECC was used as the control group and mixed with different mass fractions of CCCA (2wt%, 4wt%, 6wt%, 8wt%, 10wt%), and the mechanical, anti-chloride ion permeability and self-healing properties of PE/ECC were investigated by compressive, flexural, tensile, electric flux method and pre-loaded strain damage method, and the self-healing products were analyzed by XRD and SEM-EDS for their physical composition, microscopic morphology and elemental composition. The results show that: The mechanical and anti-chloride ion permeability of PE/ECC increase and then decrease with the increase of CCCA doping, and when the doping of CCCA is 4wt%, the mechanical and anti-chloride ion permeability of PE/ECC is most obviously improved by CCCA, and the compressive strength, flexural strength and ultimate tensile stress increase by 55.5%, 10.8%, and 79.4%, respectively. The ultimate tensile strain does not change much, and the electrical flux decreases by 38.6%. The self-healing test shows that the recovery rate of tensile strength and strain energy of PE/ECC is significantly improved after doping with CCCA, and the self-healing performance is enhanced. When the pre-damage strain is 0.5%, the tensile strength and strain energy of PE/ECC specimens doped with CCCA are higher than those of the original matrix after 84 days of maintenance, which are 10.41% and 2.83% higher than those of the original matrix, respectively. The tensile strength and strain energy of PE/ECC specimens without CCCA are lower than those of undamaged specimens under three strain damages. The XRD and SEM-EDS results show that the CaCO3, calcium silicate hydrate (C-S-H), and ettringite (AFt) intensity diffraction peaks increase in the hydration products of PE/ECC with CCCA, and the self-healing products are mainly C-S-H crystals, and the distribution is denser in the PE/ECC with CCCA.

     

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