不同工艺制备的花岗岩洞渣机制砂特性及混凝土性能比较

为掌握隧道洞渣采用不同干法工艺制备的机制砂品质特性及对混凝土性能的影响，测定砂石联产干法工艺机制砂（代号CMS）和制砂楼单产干法工艺机制砂（代号SMS）的性能指标，对比研究CMS和SMS 2种机制砂配制的C35混凝土的工作性、抗压强度、干缩和抗冻性及石粉含量在5%~14%变化对混凝土性能的影响。结果表明： 1）SMS机制砂的亚甲蓝（MB）值、压碎指标等核心指标显著优于CMS机制砂； 2）相同石粉含量下，CMS机制砂混凝土达到同等工作性所需减水剂掺量显著高于SMS机制砂混凝土，抗压强度、抗冻性能低于SMS机制砂混凝土，干缩率高于SMS机制砂混凝土； 3）石粉含量增加对CMS机制砂和SMS机制砂的MB值及混凝土的工作性、强度和耐久性的影响规律和程度有明显不同，建议SMS机制砂中允许石粉含量为10%，CMS机制砂允许石粉含量为5%。

Comparative Analysis of Characteristics of Granite Manufactured Sand Prepared with Tunnel Muck by Different Processes and Concrete Properties

To investigate the quality characteristics of manufactured sand produced by different dry processes with granite tunnel muck and its effect on the performance of concrete, the two kinds of manufactured sand samples, CMS produced by the combination production dry process of manufactured sand and gravel and SMS produced by the separate dry process of sand manufacturing plant, are used to test their performance indexes. The workability, compressive strength, dry shrinkage, and frost resistance of C35 concrete prepared by CMS and SMS and the influence of them with the stone powder content of 5%~14% on the properties of manufactured sand concrete are examined. The results reveal the following: (1) SMS is superior to CMS in terms of methylene blue(MB) value and crushing value. (2) Under the same stone powder content, the dosage of water reducer required for the CMS concrete to achieve a same workability is significantly higher than that of the SMS concrete, the compressive strength and frost resistance of the CMS concrete is lower than those of the SMS concrete, and the dry shrinkage ratio of the CMS concrete is higher than that of the SMS concrete. (3) The influence laws and degrees of stone powder content on the MB values, workability, strength, and durability of CMS and SMS concretes vary, thus the stone powder contents in SMS and CMS are recommended to be 10% and 5%, respectively.