两种不同类型无碱液体速凝剂的性能对比研究

Comparative Study on Performance of Two Different Types of Alkali-free Liquid Accelerators

采用有机酸和无机含氟酸分别合成无碱液体速凝剂SNJ-A和SNJ-B,研究了两种不同类型速凝剂对水泥凝结时间和强度的影响,以及C40喷射混凝土各龄期的力学性能和耐久性。对比了两种无碱液体速凝剂在不同环境温度下的稳定性。结果表明:SNJ-A对水泥净浆的促凝效果在不同实验条件下比SNJ-B均更明显,但相比SNJ-B,掺SNJ-A的水泥的1 d抗压强度显著提高,掺8%SNJ-A时其1 d强度达到12.8 MPa。随着养护时间的延长,掺速凝剂SNJ-A和SNJ-B水泥的28 d抗压强度比分别为105%和95%。加入8%自制功能性掺合料,对掺两种速凝剂的C40喷射混凝土的早期和后期力学性能均有显著提升作用,且其抗氯离子渗透性能好。在环境温度20℃条件下,SNJ-A的稳定性高于SNJ-B,存储三个月后性能稳定。

Alkali free liquid accelerators SNJ-A and SNJ-B were synthesized by organic acid and inorganic fluoric acid respectively.The effects of two different types of accelerators on the setting time and strength of cement and the mechanical properties and durability of C40 shotcrete at different ages were studied.The stability of two alkali-free liquid accelerators at different ambient temperatures was compared.The results show that SNJ-A has more obvious coagulation-promoting effect on cement slurry than SNJ-B under different experimental conditions,but compared with SNJ-B cement,the 1-day compressive strength of SNJ-A cement is significantly increased,and the 1-day strength of the cement can reach 12.8 MPa when 8%SNJ-A is mixed.With the extension of curing time,the 28 d compressive strength ratio of SNJ-A and SNJ-B cement is 105%and 95%,respectively.The addition of 8%homemade functional admixture can significantly improve the mechanical properties of C40 shotcrete mixed with two kinds of accelerators at both early and late stages,and its chloride ion penetration resistance is good.At the ambient temperature of 20℃,SNJ-A has higher stability than SNJ-B,and its storage performance is stable for 3 months.