硅粉混凝土的收缩性能研究

Shrinkage performance of silica fume concrete

为了研究硅粉混凝土的收缩性能,以收缩率为表征指标,采用正交试验研究了水胶比、砂率和硅粉掺量对硅粉混凝土收缩率的影响规律,通过对数据拟合和回归分析建立了硅粉混凝土的收缩模型。试验结果表明：水胶比、砂率及硅粉掺量对硅粉混凝土收缩的影响比较显著。水胶比在0.35~0.45范围内取值越大,硅粉混凝土收缩率越小；硅粉的掺入使硅粉混凝土的收缩增大,硅粉掺量在5%~10%时收缩率增长较快,而硅粉掺量大于10%以后的收缩趋于平缓。当硅粉掺量为5%,水胶比为0.45,砂率为38%时,硅粉混凝土的收缩变形最小；硅粉混凝土的收缩模型为ε= aln（ t）＋b ,在显著性水平α=0.01下其相关关系显著,应用该模型可以预测和设计硅粉混凝土的收缩性能。

In order to investigate the shrinkage performance of silica fume concrete, an orthogonal experiment was adopted to study the influence of water-cement ratio, sand ratio and silica fume dos-age on the shrinkage performance using the shrinkage ratio as the index. On the basis of the work, test data regression analysis was carried out to establish a shrinkage model of silica fume concrete. The results show that the water-cement ratio, sand ratio and silica fume dosage have significant influ-ence on the shrinkage of concrete. The shrinkage ratio decreases with the increase of water-cement ratio from 0. 35 to 0. 45. With the increase of sand ratio, the shrinkage ratio decreases and then de-clines, and it reaches the minimum when the sand ratio is 38%. Silica fume leads to the increase of concrete shrinkage, and the shrinkage ratio increases faster when the silica fume dosage is between 5% to 10%. The ratio increases slower after the silica fume dosage is more than 10%. The shrink-age ratio of silica fume concrete is the minimum when the concrete is made with 0 . 45 of water-ce-ment ratio, 38% of sand ratio and 5% of silica fume dosage. F test further shows that the shrinkage model of silica fume concreteε=aln（t） ＋b is significant when the significant levelαis 0. 01. The model can be used to predict or design shrinkage performance of silica fume concrete.riance analysis.