钙铝质矿相对碱激发矿渣氯离子固化能力的影响研究

Influences of Calcium and Aluminum Mineral Phases on Chloride Binding Capacity of Alkali-Activated Slag

本文提出了一类改性碱激发矿渣胶凝材料,通过在原材料中掺入额外的钙、铝质矿相(Ca(OH)_(2)和γ-Al_(2)O_(3)),促进材料基体中的Friedel’s盐(F盐)在氯离子存在条件下的形成,进而提升胶凝材料的氯离子固化能力。本研究探讨了钙、铝质矿物含量对碱矿渣反应产物组成、氯离子固化量以及力学性能的影响。结果表明,钙、铝质矿相的额外补充可显著提高胶凝材料的氯离子固化能力,同时体系的m(Ca)/m(Al)与该能力的相关性较高。物相分析结果表明,钙质矿相的补充使得反应产物中拥有富余的Ca(OH)_(2),在氯盐侵蚀作用下,富余的Ca(OH)_(2)全部转化为F盐或其他物相,证实了体系氯离子固化能力的增强得益于F盐的形成,即得益于化学固氯能力的提升。抗压强度测试结果,表明钙质矿物的掺入对力学性能存在一定负面影响,而铝质矿相的掺入则能够在一定程度上弥补强度损失。

In this paper,a modified alkali-activated slag cementitious material was proposed by applying calcium and alumina mineral phases(Ca(OH)_(2)and γ-Al_(2)O_(3)) as partial replacement of slag,aiming at promoting the formation of Friedel’s salt(F salt) in the matrix when in the presence of chloride,and improving the chloride binding capacity.The effects of calcium and aluminum mineral phase content on reaction products,chloride binding capacity and mechanical properties were discussed.The results show that the addition of calcium and aluminum mineral phases improves the chloride binding capacity of alkali-activated slag,and the mass ratio of Ca(OH)_(2)to γ-Al_(2)O_(3)is highly related to this capacity.XRD analyses show that there exists unreacted Ca(OH)_(2)within the reaction products,and all those Ca(OH)_(2)transform into F salt or other phases after chloride attack.It is demonstrated that the enhancement of chloride binding capacity is attributed to the formation of F salt.The compressive strength results indicate that the addition of Ca(OH)_(2)exhibits a negative impact,while the γ-Al_(2)O_(3)can compensate for the strength loss due to the Ca(OH)_(2)addition.