铁尾矿砂再生混凝土的力学及耐久性能研究  

Study on mechanics and durability of iron tailings recycled concrete

作　　者：陶亚平 赖天文[2] TAO Yaping;LAI Tianwen(Gansu Highway Traffic Construction Group Co.,Ltd.,Lanzhou 730000,China;School of Civil Engineering,Lanzhou Jiaotong University,Lanzhou 730070,China)

机构地区：[1]甘肃省公路交通建设集团有限公司,兰州730000 [2]兰州交通大学土木工程学院,兰州730070

出　　处：《功能材料》2023年第3期3143-3148,共6页Journal of Functional Materials

基　　金：国家自然科学基金项目(52168058)。

摘　　要：以C30混凝土为再生粗骨料,采用铁尾矿砂取代天然河砂,制备出不同铁尾矿砂取代率(0,25%,50%,75%和100%(质量分数))的再生混凝土。研究了不同铁尾矿砂取代率对再生混凝土力学性能、微观形貌、耐久性能的影响。结果表明,随着铁尾矿砂取代率的增加,再生混凝土的抗压强度、抗折强度、劈裂抗拉强度均表现出先增高后降低的趋势,50%(质量分数)铁尾矿砂取代率的再生混凝土力学性能最佳;掺入适量的铁尾矿砂能够填充再生混凝土骨料之间的裂缝和孔隙,提高再生混凝土的结构致密性,改善混凝土的微观结构;50%(质量分数)铁尾矿砂取代率的再生混凝土在碳化处理28 d后的碳化深度最低为4.1 mm,抗碳化性能最优;冻融循环80次后,50%(质量分数)铁尾矿砂取代率的再生混凝土的相对动弹性模量最大为94.53%,质量损失率最低为-0.11%,抗冻性能最佳。综合可知,当铁尾矿砂的取代率为50%(质量分数)时,可以有效改善再生混凝土的力学性能、微观形貌和耐久性能。Using C30 concrete as recycled coarse aggregate and iron tailing sand instead of natural river sand,recycled concrete with different iron tailing sand replacement rates(0,25 wt%,50 wt%,75 wt%and 100 wt%)was prepared.The effects of different iron tailings replacement rate on the mechanical properties,micro morphology and durability of recycled concrete were studied.The results showed that the compressive strength,flexural strength and splitting tensile strength of recycled concrete increased first and then decreased with the increase of iron tailings sand replacement rate,and the mechanical properties of recycled concrete with 50 wt%iron tailings sand replacement rate were the best.Adding an appropriate amount of iron tailings could fill the cracks and pores between recycled concrete aggregates,improved the structural compactness of recycled concrete and improved the microstructure of concrete.The carbonation depth of recycled concrete with 50 wt%iron tailings sand replacement rate after 28 d of carbonation treatment was 4.1 mm,and the carbonation resistance was the best.After 80 freeze-thaw cycles,the relative dynamic elastic modulus of recycled concrete with 50 wt%iron tailings sand replacement rate was 94.53%,the mass loss rate was-0.11%,and the frost resistance was the best.It can be seen that when the replacement rate of iron tailings sand is 50 wt%,the mechanical properties,micro morphology and durability of recycled concrete can be effectively improved.

关 键 词：铁尾矿砂 再生混凝土 力学性能 耐久性能 微观形貌 

分 类 号：TU528.09[建筑科学—建筑技术科学]