燧石粉对ASR膨胀性抑制作用的研究

Inhibiting Effect of Flint Powder on Expansion of ASR

当存在碱硅酸反应风险时,如何抑制混凝土的膨胀破坏是很重要的。本文探讨将磨细碱活性骨料作为混凝土掺合料,研究其对ASR膨胀性的抑制作用。文中对比燧石粉不同比表面积和不同掺量的胶砂试件,采用快速砂浆棒法测定其在各龄期膨胀率,并结合扫描电子显微镜(SEM)和能谱分析(EDS),研究磨细燧石粉对于ASR(Alkali-Silica Reaction,ASR)膨胀性的影响。结果表明:通过掺加一定比表面积和掺量燧石粉可以有效地抑制胶砂试件因ASR产生的膨胀;SEM和EDS分析显示掺入一定比表面积和适量的燧石粉后,燧石骨料周围碱硅酸凝胶产量减少,说明燧石粉的掺入可以有效减少活性骨料表面发生ASR;同时水化硅酸钙的钙硅比亦有所降低,提升水化硅酸钙的固碱能力,进一步有效抑制ASR。本研究结果能为使用潜在碱活性骨料时,抑制其ASR反应措施提供一定的参考。

The influence of adding different fineness and proportion flint powder on expansion of AlkaliSilica Reaction（ASR） in mortar samples were investigated by comparing the expansion rate in different ages,SEM images and energy spectrum analysis（EDS） of the samples. Adding appropriate amount flint powder with different fineness can effectively inhibit the expansibility of the specimens caused by ASR.SEM images and the results of EDS show that the amount of alkali silicate gel around flint aggregates decrease when adding appropriate flint powder. It proved that flint powder have the potential to inhibit ASR. And the reactive flint powder decrease Ca/Si mole ratio,which increases Na ions fixation capacity of CSH,and improves the inhibition of ASR. The results can provide some reference for inhibiting the ASR reaction measures when using latent alkali active aggregates.