纳米二氧化硅对早期负温混凝土力学性能的影响

为降低负温给混凝土结构带来的性能损失，在添加定量防冻剂的基础之上添加低掺量纳米二氧化硅，研究其不同掺量对早期负温养护混凝土工作性能、微观结构及其抗压强度的发展变化情况，并通过二次曲线回归分析，建立各龄期不同掺量抗压强度预测回归关系式。结果表明，纳米二氧化硅可以有效改善早期负温养护混凝土微观水化结构，宏观上表现为力学性能的提高，综合考虑最佳掺量为1.5%，并且回归分析所得到的抗压强度预测值与实验结果能够较好契合。

Effect of Nano-SiO2 on Mechanical Properties of Early Negative Temperature Concrete

In order to reduce the performance loss of concrete structure caused by negative temperature, low content Nano-SiO2 was added on the basis of adding quantitative antifreezing agent. the development and changes of different content of nano-silica on the working performance, microstructure and compressive strength of early negative temperature curing concrete were studied, and the prediction regression formula of compressive strength of different content in each age was established by quadratic curve regression analysis. The results show that nano-silica can effectively improve the micro-hydration structure of early negative temperature curing concrete, which shows the improvement of mechanical properties macroscopically, and the optimum content is 1.5%. And the predicted compressive strength obtained by regression analysis is in good agreement with the experimental results.