络合型外加剂与矿物掺合料对水泥基材料结构与性能的影响研究

Effect of Chelating Functional Agent and Mineral Admixtures on the Structure and Properties of Cement-based Materials

络合型外加剂(络合剂)是一种能促进水泥基材料自修复的添加剂。通过孔隙率、力学性能、裂缝自修复测试和扫描电镜表征,研究了络合剂和矿物掺合料协同作用对水泥砂浆结构与性能的影响。研究结果表明:络合剂能够提高水泥砂浆的力学强度,降低总孔隙率,提高裂缝自修复能力;络合剂和矿物掺合料同时使用能进一步改善水泥砂浆的性能;当龄期为28d时,与普通水泥砂浆相比,掺加粉煤灰和络合剂的水泥砂浆总孔隙率降低了42.2%;掺加矿粉和络合剂的水泥砂浆的抗折抗压强度分别比普通水泥砂浆的抗折抗压强度提高了24.7%和40.7%。掺加络合剂和粉煤灰的水泥砂浆表面宽度为0.3mm的裂缝在养护28d后自愈合。扫描电镜观察显示,掺加络合剂和矿物掺合料的砂浆孔隙中,有大量水化硅酸钙和碳酸钙生成。

Chelating functional agent(chelating agent)is an additive which can promote self-healing of cement-based materials.In this paper,the synergistic effect of chelating agent and mineral admixtures on the structure and properties of mortar is investigated by the porosity,mechanical properties,crack selfhealing and scanning electron microscopy(SEM).The results show that the chelating agent can enhance the mechanical strength of mortar,reduce the total porosity and improve the self-healing ability of cracks.The simultaneous use of chelating agent and mineral admixtures can further improve the performance of mortar.After curing for 28 days,the total porosity of mortar with fly ash and chelating agent is reduced by 42.2%compared with control mortar,the flexural and compressive strength of mortar with slag and chelating agent are 24.7%and 40.7%higher than that of control mortar,respectively.The surface cracks with a width of 0.3 mm on the mortar with chelating agent and fly ash can be closed after curing for 28 days.Scanning electron microscope observation shows that a large number of calcium silicate hydrate and calcium carbonate are formed in the pores of the mortar with chelating agent and mineral admixtures.