纳米CaCO_(3)改性大掺量沸石粉混凝土性能研究

Study on the Properties of Nano-CaCO_(3)Modified Large Amount of Zeolite Powder Concrete

为研究纳米CaCO_(3)对大掺量沸石粉混凝土的性能优化作用,分别以单掺沸石粉和复掺沸石粉、纳米CaCO_(3)(NC)改性的方式制备高性能混凝土(HPC),并测试其工作性能、力学性能、抗氯离子渗透性及微观结构,研究NC对大掺量沸石粉混凝土的性能影响及作用机理。结果表明,大掺量沸石粉会降低混凝土工作性能和早期力学性能,但能够提高抗氯离子渗透性能和后期力学性能,当沸石粉掺量为20%时,HPC的7 d、28 d、90 d抗压强度分别为基准组的89.52%、97.60%、101.07%,劈裂抗拉强度为基准组的92.65%、99.85%、102.62%,抗氯离子渗透性能较基准组提高5.64%;在此基础上复掺NC后,沸石粉混凝土的负面影响得到改善,抗氯离子渗透性进一步增强。当NC掺量为1.0%时,HPC 7 d、28 d、90 d抗压强度分别较未掺NC时提高12.34%、8.90%、5.91%,劈裂抗拉强度提高14.76%、11.30%、7.95%,抗氯离子渗透性能提高20.92%。NC能够促进沸石粉水泥体系水化反应,优化水化产物形态,细化浆体孔隙结构,提高混凝土的致密性。当沸石粉掺量为20%,NC掺量为1.0%时,大掺量沸石粉混凝土的各项性能达到较优水平。

In order to study the performance optimization effect of nano-CaCO_(3)on large amount zeolite powder concrete,HPC was prepared by single-doped zeolite powder,multi-doped zeolite powder and NC modification,respectively.The effect and mechanism of NC on the performance of large amount zeolite powder concrete were studied by working performance,mechanical properties,chloride ion permeability resistance and microstructure.The results show that when the amount of zeolite powder is 20%,the 7 d,28 d and 90 d compressive strength of HPC is 89.52%,97.60%and 101.07%of benchmark group,respectively,and the splitting tensile strength is 92.65%,99.85%and 102.62%of benchmark group,the chloride ion permeability resistance is 5.64%higher than that of the benchmark group.After adding NC on this basis,the negative impact of zeolite powder concrete is improved,and the chloride ion permeability is further enhanced.When NC content is 1.0%,compared with HPC without NC,the 7 d,28 d and 90 d compressive strength is increased by 12.34%,8.90%and 5.91%,respectively,the splitting tensile strength is increased by 14.76%,11.30%and 7.95%,and the chloride ion permeability is increased by 20.92%.NC could promote the hydration reaction of zeolite powder cement system,optimize the morphology of hydration products,refine the pores of slurry structure,and improve the compactness of concrete.When the content of zeolite powder is 20%and the content of NC is 1.0%,the properties of large amount of zeolite powder concrete reach the optimal level.