机制砂T梁C55混凝土配制及性能研究

针对肯尼亚"一带一路"建设工程内马铁路项目沿线缺乏河砂的现状,采用肯尼亚当地原材料,从胶凝材料体系优化、粉煤灰掺量、砂率、机制砂石粉含量等对混凝土工作性、力学性能和耐久性影响的角度对机制砂T梁C55混凝土配合比进行了研究。结果表明:采用机制砂可以配制出满足现行铁路标准要求的T梁C55混凝土,砂率在36%～44%之间,抗压强度均满足C55混凝土的设计强度,砂率36%、38%时混凝土轻微泌水及流动性稍差,砂率40%～44%混凝土状态较好;石粉含量3.2%的机制砂混凝土出现泌水现象,结合标准要求和试验情况,石粉含量推荐控制在5%～7%;机制砂混凝土含气量小于河砂混凝土,密度比河砂混凝土大;机制砂混凝土抗压强度比河砂混凝土大,但是相差不多;机制砂T梁C55混凝土耐久性与河砂混凝土相差不大。

Study on the preparation and properties of C55 concrete of mechanism sand T beam

Accord to the present situation of Kenya The Belt and Road Kenya Nairobi-Naivasha Standard Gauge Railway Project construction project along the river sand by lack of local raw materials,Kenya,from the angle of cementitious material system optimization,fly ash,sand,sand content rate mechanismon workability,mechanical properties and durability influence mechanismof sand T beamC55 concrete mix ratio was studied.The results show that the prepared T beams C55 concrete meet the standard requirements of the current railway adopts the mechanism of sand,sand ratio between 36%~44%,the compressive strength could meet the design strength of C55 concrete,36%sand ratio and 38%concrete slight bleeding and less liquid,sand ratio 40%~44%better mixed concrete.Machine-made sand the concrete content of 3.2%powder bleeding,according to the standard requirements and test conditions,the content of stone powder recommended control in 5%~7%.The mechanism of sand concrete containing gas is less than the river sand concrete,bulk density than river sand concrete.The compressive strength of manufactured sand concrete than river sand concrete,but not much difference;mechanism of sand T beamC55 concrete river sand concrete durability with little difference.