钼尾矿砂掺量对超高性能混凝土性能的影响研究

Study on the Effect of Molybdenum Tailings Content on the Performance of Ultra-high Performance Concrete

将钼尾矿进行磨细处理制备成钼尾矿砂取代UHPC中的石英砂制备超高性能混凝土(UHPC),研究钼尾矿砂对UHPC工作性能、力学性能、抗氯离子渗透性能以及干燥收缩性能的影响规律。结果表明:随着钼尾矿砂掺量的增加,UHPC的扩展度呈先增大后减小的趋势,当钼尾矿砂掺量为40%时,UHPC的扩展度最大,为616 mm,工作性能最好;在标准养护条件下,随着钼尾矿砂掺量的增加,各龄期UHPC的抗压强度均呈不同程度的下降;在90 ℃蒸养3 d条件下,UHPC的抗压强度随着掺量的增加呈先上升后下降的趋势,当钼尾矿砂掺量小于40%时,UHPC的抗压强度上升至峰值,相较于钼尾矿砂掺量为0%时提高了6.5%;对于UHPC抗折强度而言,无论是标准养护或蒸汽养护方式,随着钼尾矿砂掺量的增加,UHPC的抗折强度均是下降的;随着钼尾矿砂掺量的增加,UHPC的抗氯离子渗透性能及干燥收缩性能均呈先提高后降低的趋势,当钼尾矿砂掺量为40%时,UHPC的抗氯离子渗透性能及干燥收缩性能最佳。

This paper describes the preparation of ultra-high performance concrete(UHPC)by grinding molybdenum tailings into molybdenum tailings sand instead of quartz sand in UHPC,and investigates the influence of molybdenum tailings sand on the workability,mechanical properties,chloride ion penetration resistance,and drying shrinkage performance of UHPC.The results show that with the increase of molybdenum tailings content,the expansion degree of UHPC shows a trend of first increasing and then decreasing.When the molybdenum tailings content is 40%,the expansion degree of UHPC is the highest,at 616 mm,and the working performance is the best;under standard curing conditions,as the content of molybdenum tailings increases,the compressive strength of UHPC at different ages decreases to varying degrees;under the condition of steam curing at 90℃for 3 days,the compressive strength of UHPC shows a trend of first increasing and then decreasing with the increase of dosage.When the dosage of molybdenum tailings is less than 40%,the compressive strength of UHPC rises to its peak,which is 6.5%higher than when the dosage of molybdenum tailings is 0%;for the flexural strength of UHPC,whether it is standard curing or steam curing,the flexural strength of UHPC decreases with the increase of molybdenum tailings content;with the increase of molybdenum tailings content,the resistance to chloride ion penetration and drying shrinkage performance of UHPC show a trend of first increasing and then decreasing.When the molybdenum tailings content is 40%,the resistance to chloride ion penetration and drying shrinkage performance of UHPC is the best.