HEMC改性水泥砂浆在硫酸盐侵蚀作用下的力学性能

Mechanical Properties of HEMC Modified Cement Mortars Exposed to Sulfate Attack

研究了羟乙基甲基纤维素(HEMC)改性水泥砂浆在硫酸盐侵蚀作用下的力学性能演变规律及HEMC的作用机理.结果表明:HEMC会明显降低水泥砂浆在硫酸盐侵蚀作用下的抗压强度和抗折强度,但能显著提高黏结抗拉强度;硫酸盐短期侵蚀作用能提高HEMC改性水泥砂浆的力学性能,但长期侵蚀作用会显著降低力学性能;HEMC改性水泥砂浆在硫酸盐长期侵蚀作用下仍具有优良的力学性能,原因在于HEMC能优化水泥砂浆的孔结构及内部界面结构,显著降低水分和硫酸根离子的渗透和扩散;就硫酸盐长期侵蚀作用下的力学性能而言,HEMC在水泥砂浆中存在着较佳掺量范围.

Mechanical properties evolution of cement mortars modified by hydroxyethyl methyl cellulose(HEMC)subjected to sulfate attack and the improvement mechanisms of HEMC were investigated.The results show that HEMC can greatly decrease flexural strength and compressive strength,but increase tensile bond strength of cement mortar subjected to sulfate attack.The short-term sulfate attack is beneficial to improve mechanical properties of HEMC modified cement mortar,but long-term sulfate attack significantly reduces mechanical properties.However,HEMC modified cement mortars still assume excellent mechanical properties after exposed to sulfate attack,the reason is due to that HEMC can optimize the pore structure and interfacial zones and remarkably reduces the water and ions penetration in cement mortar.Besides,as for mechanical properties under long-term sulfate attack,there exists an optimal dosage range of HEMC in cement mortar.