MKPC浆体界面黏结机制及抗侵蚀性能试验研究

Experimental study on interfacial bond mechanism and erosion resistance of MKPC slurry

试验对比了掺合料改性的MKPC浆体与普通硅酸盐混凝土在淡水、循环水以及硫酸盐三种侵蚀环境中的黏结耐久性,并进行了黏结界面的SO42-渗透试验,最后通过SEM分析,探讨了微观机理。试验结果表明,试件在循环水中黏结强度衰减幅度最大,120 d强度损失值达91.56%,淡水环境次之,硫酸钠环境中黏结强度损失最小,120 d龄期仍有1.22 MPa的强度。随着侵蚀龄期的增长,各组试件的黏结强度都出现了不同程度的衰减,其中单掺10%偏高岭土和20%偏高岭土的两组试件,其120 d黏结强度不到1 MPa,而双掺10%偏高岭土和10%粉煤灰的黏结试件具有较好的耐久性,120 d强度衰减值仅为47.2%。SO_(4)^(2-)渗透试验表明,SO_(4)^(2-)会从MKPC浆体与普通硅酸混凝土的黏结界面逐渐渗透,随着侵蚀龄期的增长,渗透深度逐渐增大。

The bond durability of MKPC slurry modified by admixture and ordinary silicate concrete in fresh water,circulating water and sulfate erosion environment was compared,and SO42-penetration test of bond interface was carried out.Finally,the micro mechanism was discussed by SEM analysis.The results show that the strength loss of the specimens in the circulating water is the largest,91.56% in120 days,followed by fresh water,and 1.2 MPa in 120 days.With the increase of erosion age,the bond strength of each group of specimens decreased to different degrees.The bond strength of two groups of specimens with 10% MK(metakaolin)and 20% MK alone was less than1 MPa in 120 d,while the bond specimens with 10% MK and 10% FA(fly ash)had better durability,and the strength attenuation value of 120 d was only 47.2%. SO_(4)^(2-) penetration test shows that SO_(4)^(2-) will gradually penetrate from the bonding interface between MKPC paste and ordinary silica concrete,the penetration depth will gradually increase with the increase of erosion age.