二次搅拌工艺对混凝土性能影响的试验研究

针对传统混凝土搅拌工艺中存在的问题,讨论了先拌水泥砂浆法、先拌水泥净浆法、水泥裹砂法、水泥裹石法、粗细骨料全造壳法等二次搅拌工艺,研究了不同工艺流程对混凝土搅拌质量的影响,测试了不同条件下混凝土的匀质性、抗压强度指标及功率消耗,并与传统搅拌工艺进行了对比试验.在对不同工艺流程试验研究的基础上,结合目前普遍使用的双卧轴搅拌机的点,提出了提高搅拌速度的等速二次投料搅拌方案.结果表明：这种二次搅拌工艺较传统搅拌工艺能明显提高混凝土的搅拌质量和效率,改善了混凝土界面过渡区的粘结强度.

Test research on concrete performance by secondary mixing processes

Directed against the existing problems in traditional mixing process, secondary mixing techniques, such as pre-mix cement mortar, pre-mix cement paste, sand enveloped with cement paste, coarse aggregate enveloped with cement paste and aggregate enveloped with cement paste are discussed, and the effect of different mixing technological processes on concrete mixing quality is studied. The homogeneousness, compression strength of concrete and the power consumption are tested during the test, and compared with the traditional mixing method. Based on the test research of the processes combined with present used double-shall concrete mixers, the constant-speed secondary mixing process with increased mixing speed is proposed. The results indicated that the mixing quality of concrete and mixing efficiency can be improved obviously and the bond strength of the transitional among concrete interface is improved.