摘要
为研究用铁尾矿砂取代自然砂配制的混凝土的力学特性,设计了6种配比方案共计14次试验,分别进行了塌落度试验、初凝时间试验、试块密度试验、抗压强度试验、劈裂抗拉强度试验,并对各配比混凝土浇筑养护28d的试块进行SEM电镜扫描分析。结果表明:用铁尾矿砂作为细骨料加入混凝土配比中,当铁尾矿砂占总体细骨料(铁尾矿砂和自然砂之和)的比例为20%时,混凝土的和易性、凝结时间最优,块体密度最大,耐久性最好,但这一比例超过20%后,其和易性、耐久性等逐渐降低,电镜扫描结果很好的证实了混凝土的力学强度变化规律。最佳水灰比、灰砂比、外加剂掺量以第8次配比最优,以配比二的混凝土其抗压强度最大;配比二的混凝土其1,3,7d抗压强度和抗拉强度均最高,且其抗拉强度7d与28d相比相差不大,符合喷射混凝土性能的最优要求。试验结果表明,铁尾矿砂用于喷射混凝土的制备可以有效提高其性能特性,其中以配比二方案最优。
In order to study the mechanical properties of iron tailings instead of natural sand,a total of 14 tests were designed for 6 mixing schemes.The slump test,initial setting time test,block density test,compressive strength test,and splitting tensile strength test were carried out separately,and scanning electron microscopy analysis was carried out on the specimens with different mixing proportions under concrete pouring and curing for 28 days.The results showed that the iron tailings sand was added to concrete as fine aggregate,when the ratio of iron tailings sand to the total fine aggregate(the sum of iron tailings sand and natural sand)was 20%,the workability and coagulation time were optimal,the block density was the largest,and the durability was the best.But when the ratio exceeded 20%,the workability and durability gradually decreased.The scanning electron microscopy results confirmed the mechanical strength variation of concrete.The optimum water-cement ratio,limesand ratio and admixture content were obtained at the 8 th mix ratio scheme,and the compressive strength of the concrete at the second mix ratio scheme was the greatest.The compressive strength and tensile strength of the concrete at the second scheme were the highest in 1,3 and 7 days,and the tensile strength of the concrete at the second scheme was similar in 7 days and 28 days,which met the optimum requirement of shotcrete performance.The experimental results showed that the performance characteristics of shotcrete could be effectively improved by using iron tailings in the preparation of shotcrete,of which the second scheme was the best.
作者
黄正均
张英
任奋华
张磊
郭奇峰
HUANG Zhengjun;ZHANG Ying;REN Fenhua;ZHANG Lei;GUO Qifeng(School of Civil and Resource Engineering,University of Science and Technology Beijing,Beijing 100083,China;State Key Laboratory of the Education Ministry for High-Efficient Mining and Safety of Metal Mines,Beijing 100083,China)
出处
《矿业研究与开发》
CAS
北大核心
2019年第4期121-126,共6页
Mining Research and Development
基金
国家自然科学基金资助项目(51774022)
国家重点研发计划资助项目(2017YFC0804101)
关键词
铁尾矿砂
配比试验
力学特性
喷射混凝土
电镜扫描
Iron tailings sand
Proportion test
Mechanical properties
Shotcrete
Scanning electron microscope
