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对比分析我国和ACI对预拌混凝土砂石的级配标准要求,根据骨料空隙体积最小的原则,对机制砂及混合后骨料的级配进行了整体优化,得到空隙率小的骨料体系。级配优化后粗骨料的空隙率由0.463下降到0.422,细骨料的空隙率由0.372下降到0.338。用级配优化后的骨料进行了三种强度等级(C30、C40、C50)混凝土的试配,依据CF-WF理论和坍落度指标对比分析了骨料级配优化后混凝土拌合物工作性的改善情况,同时也对混凝土7d和28d的抗压强度进行了对比分析。分析结果表明:级配优化后C30、C40、C50混凝土的坍落度指标分别提高了14.2%、9.8%、13.1%;7d抗压强度分别提高了3.3MPa、3.3 MPa、3.8 MPa;28d抗压强度分别提高了7.3MPa、8.1 MPa、5.4 MPa。
According to the principle of the smallest void volume of aggregate, the grading of aggregate and mixed aggregate was optimized as a whole, the aggregate system with small porosity was obtained . The graded coarse aggregate porosity decreased from 0.463 to 0.422 and the fine aggregate porosity decreased from 0.372 to 0.338. Three grades of concrete (C30, C40, C50) were tested with the graded optimized aggregates. Based on the CF-WF theory and the slump index, the optimized aggregate mix with aggregate gradation Sexual improvement, but also on the compressive strength of concrete 7d and 28d for a comparative analysis. The results show that the indexes of slump of C30, C40 and C50 concrete increase by 14.2%, 9.8% and 13.1% respectively after optimized gradation; the compressive strength of 7d increases by 3.3MPa, 3.3MPa and 3.8MPa respectively; The intensities were increased by 7.3 MPa, 8.1 MPa and 5.4 MPa, respectively.