机制砂石粉含量对轨枕混凝土性能影响研究

Study on the influence of machine-made sand powder content on the performance of sleeper concrete

针对内马铁路沿线缺乏优质河砂需要采用机制砂生产轨枕的现状,通过混凝土工作性能、抗压强度、外观质量、静载试验,研究了不同机制砂石粉含量对轨枕高强混凝土性能的影响。结果显示:随着机制砂石粉含量的增加,混凝土含气量和增实因数减小,各龄期抗压强度均呈现一定的下降趋势,混凝土入模温度与机制砂石粉含量关系不大;各组不同石粉含量的机制砂混凝土生产的轨枕静载试验结果均合格;对轨枕外观质量而言,机制砂石粉含量最佳值为9%~11%,此时轨枕表面气泡较少、颜色均匀,外观质量良好,同时,混凝土增实因数、含气量、抗压强度符合TB/T 3275—2011要求,轨枕静载试验合格。

In view of the current situation of the lack of high quality river sand along Kenya Nairobi-Naivasha Standard Gauge Railway Project,and the need to use machine-made sand to produce sleepers,the influence of different machine-made sand powder content on the performance of the sleeper high-strength concrete have been studied through concrete workability,compressive strength,appearance quality and static load tests.The results show that as the content of machine-made sand and gravel powder increases,the air content and solidification factor of concrete decrease,and the compressive strength at each age shows a certain decline trend.There is little relationship between the concrete entry temperature and the content of machine-made sand and gravel powder.The static load test results of sleepers produced by machine-made sand concrete with different stone powder content are all qualified.For the appearance quality of sleepers,the optimum value of machine-made sand powder content is 9%~11%.At this time,the sleeper's surface bubbles are less,the color is uniform,and the quality of the outer tube is good.At the same time,the concrete consolidation factor,air content and compressive strength meet the requirements of standard TB/T 3275—2011,and the sleeper static load test is qualified.