铁尾矿粉制备高延性纤维增强水泥基复合材料

Development of engineered cementitious composites containing iron ore tailing powders

探索采用铁尾矿粉取代粉煤灰作为矿物掺合料制备高延性纤维增强水泥基复合材料（ECC）的可行性,重点研究铁尾矿粉掺量对ECC的拉伸特性和抗压强度的影响,并比较所研发的新型铁尾矿粉ECC与传统粉煤灰ECC的宏观力学性能.研究发现,采用铁尾矿粉作为矿物掺合料制备高延性纤维增强水泥基复合材料是可行的.在同等矿物掺合料掺量下,铁尾矿粉ECC的强度性能低于粉煤灰ECC,但表现出更强的拉伸延性.在所研制的铁尾矿粉ECC中,当铁尾矿粉与水泥质量比为1.2-2.2时,ECC的28 d抗压强度为36.7-54.2 MPa,满足一般混凝土结构对抗压强度的要求.此时,ECC的28 d极限拉伸应变为3.4%-4.3%,铁尾矿的总用量占固体基体原材料总质量的66.6%-77.0%.

The substitution of iron ore tailing powders（ IP） for fly ash as mineral admixtures was studied in the development of engineered cementitious composites（ ECC）. The focus was placed on the effect of IP content on the tensile properties and compressive strength of ECC. The mechanical properties of ECC with IP were also compared with those of traditional ECC with fly ash. Experimental results show that it is feasible to use IP as mineral admixtures to produce high-ductile ECC. ECC with IP exhibits a lower strength performance but a higher ductility under tensile load than ECC with fly ash at the same addition of mineral admixtures. ECC with an IP / cement mass ratio of 1. 2- 2. 2 shows a 28-d compressive strength of 36. 7- 54. 2 MPa,which meets the compressive strength requirement of normal concrete structures,and a 28-d tensile ductility of 3. 4%- 4. 3%. The amount of iron ore tailings in those mixtures accounts for 66. 6%- 77. 0% of the total solid matrix ingredients of ECC.