铁尾矿砂绿色混凝土的制备与性能研究  

Study on preparation and properties of green concrete with iron tailings

作　　者：李致远[1] 陈峰[1] LI Zhiyuan;CHEN Feng(College of Engineering,Fujian Jiangxia University,Fuzhou 350108,China)

机构地区：[1]福建江夏学院工程学院,福州350108

出　　处：《功能材料》2023年第6期6230-6236,共7页Journal of Functional Materials

基　　金：国家自然科学基金项目(U1605242);福建省科技厅自然科学基金项目(2022J01963,2023J01130625);福建省教育厅项目(JAT220243)。

摘　　要：以C40废弃混凝土为再生骨料,制备出了不同铁尾矿砂取代率的绿色混凝土,研究了铁尾矿砂的比例对绿色混凝土力学性能、微观形貌、耐久性的影响。结果表明,铁尾矿砂具有潜在火山灰活性,添加到混凝土中后没有生成新的水化产物,但促进了水泥熟料的消耗,加速了水化产物的生成,使过渡区形貌和水化产物的致密度得到改善,且提高了C-S-H凝胶的分布均匀性。随着铁尾矿砂取代率的增大,绿色混凝土的抗压强度、抗折强度和劈裂抗拉强度均表现出先增大后降低的趋势,当铁尾矿砂的取代率为60%时,绿色混凝土的抗压强度、抗折强度和劈裂抗拉强度达到最大值,分别为43.10,5.52和3.66 MPa。养护龄期28 d,当铁尾矿砂的取代率为60%时,绿色混凝土的碳化深度最低为5.2 mm,氯离子扩散系数最低为1.18×10^(-8)cm^(2)/s,收缩率最低为-0.207%,具有优异的耐久性。综合分析可知,铁尾矿砂取代率的最佳比例为60%。Using C40 waste concrete as recycled aggregate,green concrete with different replacement rates of iron tailings was prepared.The effects of the proportion of iron tailings on the mechanical properties,microscopic morphology and durability of green concrete were studied.The results showed that iron tailing sand had potential pozzolanic activity and didn’t generate new hydration products when added to concrete,but promoted the consumption of cement clinker,accelerated the generation of hydration products,improved the morphology of transition zone and the density of hydration products,and improved the distribution uniformity of C-S-H gel.With the increase of replacement rate of iron tailings,the compressive strength,flexural strength and splitting tensile strength of green concrete showed a trend of first increasing and then decreasing.When the replacement rate of iron tailings was 60%,the compressive strength,flexural strength and splitting tensile strength of green concrete reached the maximum value,which was 43.10,5.52 and 3.66 MPa,respectively.With the curing period of 28 d,when the replacement rate of iron tailings was 60%,the minimum carbonation depth of green concrete was 5.2 mm,and the minimum chloride diffusion coefficient was 1.18×10^(-8) cm ^(2)/s,the minimum shrinkage was-0.207%,showing excellent durability.Comprehensive analysis shows that the best proportion of iron tailings replacement rate is 60%.

关 键 词：铁尾矿砂 绿色混凝土 力学性能 耐久性 收缩性能 

分 类 号：TU528.04[建筑科学—建筑技术科学]