细集料改性对全轻混凝土性能的影响

Influence of Modified Fine Aggregate on All-light-weight Aggregate Concrete Properties

在轻细骨料表面喷涂不同浓度(质量浓度)憎水剂溶液对其改性处理,并通过力学性能实验及热工性能实验分析轻细骨料改性处理对全轻混凝土性能的影响。实验结果表明,憎水剂用量增加,全轻混凝土的抗压强度呈先增加而后降低的特性,而全轻混凝土的导热系数则表现为先快速降低而后基本保持不变的趋势。分析憎水剂浓度对全轻混凝土性能影响规律,结果表明,憎水剂溶液浓度为1%、憎水剂溶液与玻化微珠质量比为1∶1时,全轻混凝土各项性能表现为最优,其28 d抗压强度为12.8 MPa,导热系数为0.302 W/(m·K),与对比试件相比,抗压强度提高约30%,而导热系数基本不变。有机硅憎水剂在轻细骨料形成的一层致密的薄膜,改善了轻细骨料的表面性能,减少了混凝土总用水量。但有机硅憎水剂也增加了颗粒之间的排异性能,用量过多将导致混凝土力学性能下降。因此应选择合适的有机硅溶液浓度,尽可能高的开发混凝土强度潜能。

The effects of modified fine aggregate on the all-light-weight aggregate concrete properties are studied. The lightweight fine aggregate was modified by different concentrations of hydrophobic solution. How modification treatment of lightweight fine aggregate works on the performance of all-light-weight aggregate concrete is analyzed through mechanics performance experiment and thermal performance experiment. The experimental results show that, with the hydrophobic agent dosage increases, the compressive strength of all-light-weight aggregate concrete increases first and then decreases, while the coefficient of thermal conductivity trend of all-light-weight aggregate concrete decreases rapidly and then remains unchanged. Effect of hydrophobic agent concentration on all-light-weight aggregate concrete property is analyzed. Results show that, when the concentration of hydrophobic agent is 1% and hydrophobic agent with vitrified microsphere is 1 ： 1, the performance of lightweight concrete is the best the 28 d compressive strength can reach 12.8 MPa, coefficient of thermal conductivity is 0. 302 W/（ m· K）. In comparison with the contrast test-piece, the compressive strength increases about 30% while the coefficient of thermal conductivity remains unchanged. Silicone hydrophobic agent is formed on the light fine aggregate with a dense film which improves the performance of light aggregate concrete and reduces the total water consumption of concrete at the same time. However, silicone hydrophobic agent increases the rejection property between particles, which will leads to the mechanics performance of concrete decrease. Proper concentration of silicone solution should be selected for the development potential of concrete as high as possible.