摘要
选择水泥体系和碱激发体系两种胶凝材料体系制备充填材料,研究了料浆浓度、灰砂比、黄金尾矿掺量等因素对充填材料工作性能和力学性能的影响规律。结果表明:水泥体系和碱激发体系制备的充填材料均随着料浆浓度的降低,流动度提高,各龄期抗折、抗压强度降低,随着灰砂比的降低各龄期抗折、抗压强度降低。黄金尾矿掺量占集料50%的水泥体系充填材料标准养护7 d后产生大量的裂纹,导致28 d抗折强度低于7 d抗折强度,28 d抗压强度与7 d抗压强度基本不变。黄金尾矿掺量占集料30%的水泥体系充填材料和黄金尾矿掺量占集料50%的碱激发体系充填材料抗折、抗压强度随着龄期逐渐增加,且未产生大量的裂纹。充填材料试块产生裂纹的主要原因是黄金尾矿中黄铁矿与氧和水接触时发生氧化,形成酸和硫酸盐,然后与水泥的矿物相铝酸三钙和水化产物氢氧化钙反应,生成钙矾石和石膏,反应过程会发生膨胀,最终导致充填材料强度降低。
Two kinds of cementitious materials systems which are cement system and alkali-activated system were selected to prepare backfill material.The effects of slurry concentration,ratio of powder to sand and dosage of gold tailings on the working performance and mechanical properties of backfill material were studied.The results show that the fluidity of the backfill material prepared by cement system and alkali-activated system increased,its flexural and compressive strength decreased with decreasing of slurry concentration.The flexural and compressive strength of backfill materials prepared by cement system and alkali-activated system decreased with decreasing of ratio of powder to sand.A large number of cracks appeared in the backfill material prepared by cement system with 50%gold tailings at 7 days under standard curing.The flexural strength of the backfill material prepared by cement system with 50%gold tailings at 28 d is lower than that of the backfill materials at 7 d,and the compressive strength of the backfill material prepared by cement system with 50%gold tailings at 28 d is almost the same as that of the backfill material at 7 d.The flexural and compressive strength of the filling material of prepared by cement system with 30%gold tailings and prepared by alkali-activated system with 50%gold tailings increased with the curing age,and there were not cracks.The main reason for the crack of the backfill material is that the pyrite in the gold tailings oxidizes when it comes into contact with oxygen and water,forming acid and sulfate,and then reacts with C3A of the cement and calcium hydroxide of hydration product,ettringite and gypsum are formed,and the reaction process expands,eventually the strength of the filling material are decreased.
作者
黄天勇
房桂明
张莹
常宇
陈旭峰
HUANG Tianyong;FANG Guiming;ZHANG Ying;CHANG Yu;CHEN Xufeng(State Key Laboratory of Solid Waste Reuse for Building Materials,Beijing 100041,China;Beijing Building Materials Academy of Sciences Research,Beijing 100041,China;Beijing University of Civil Engineering and Architecture,Beijing 102616,China)
出处
《混凝土》
CAS
北大核心
2022年第4期150-153,共4页
Concrete
基金
国家重点研发计划项目(2018YFC1903602)。
关键词
黄金尾矿
充填材料
碱激发
水泥
黄铁矿
gold tailings
backfill material
alkali-activated
cement
pyrite
