碱矿渣胶凝材料的固砂特性及抗硫酸盐侵蚀性能  

Consolidation Characteristics and Sulfate Resistance of Alkali-activated Slag Cementitious Materials

作　　者：孙道胜 叶哲 刘开伟 王爱国 管艳梅 陈东 SUN Daosheng;YE Zhe;LIU Kaiwei;WANG Aiguo;GUAN Yanmei;CHEN Dong(Anhui Key Laboratory of Advanced Building Materials,School of Materials and Chemical Engineering,Anhui Jianzhu University,Hefei 230022,China;School of Civil and Engineering,Anhui Jianzhu University,Hefei 230022,China)

机构地区：[1]安徽建筑大学材料与化学工程学院,安徽省先进建筑材料重点实验室,合肥230022 [2]安徽建筑大学土木工程学院,合肥230022

出　　处：《材料导报》2020年第10期10061-10067,共7页Materials Reports

基　　金：安徽省自然科学基金(1708085QE102,190808ME173);国家科技支撑计划(2016YFC0701700);国家自然科学基金(51578004,51608004,51778003)。

摘　　要：碱激发注浆材料作为一种路基、基础加固的环保胶凝材料,其水化产物中不仅没有氢氧化钙,而且部分水化产物还具有吸附硫酸根离子的效果,因而碱激发注浆材料抗硫酸盐侵蚀效果优异,具有广阔的应用前景。本研究对比分析了氧化镁激发矿渣(GGBS-MgO)、氧化钙激发矿渣(GGBS-CaO)与水泥(PC)三种材料固结砂的固结特性及抗硫酸盐侵蚀性能,通过外观、无侧限抗压强度、质量变化率、物相与微结构变化揭示了其抗硫酸盐侵蚀的机理。结果表明:CaO激发可以获得相对更高的pH值,有利于矿渣中玻璃体内O-Si-O、O-Al-O键的断裂,形成更多的水化产物,从而具有更好的固结特性。与水泥固结砂相比,GGBS-MgO、GGBS-CaO固结砂的28 d无侧限抗压强度分别提升了42.2%和101.2%。在5%(质量分数)Na 2SO 4溶液中浸泡150 d时,PC组中氢氧化钙被消耗形成钙矾石和大量石膏等腐蚀产物,引起试件明显开裂,孔隙率增长82.8%,无侧限抗压强度仅为0.41 MPa;而GGBS-MgO、GGBS-CaO则在硫酸盐的持续激发下继续水化,并能吸附侵入的硫酸根离子形成类水滑石,强度持续增长,抗硫酸盐侵蚀性能明显提高。As a kind of low-carbon and environment-friendly cementing material for roadbed and foundation reinforcement,alkali-activated geopolymer grouting material not only has no calcium hydroxide in its hydration products,but also some hydration products can provide adsorption of sulfate ions,with excellent anti-sulfate erosion effect and broad application prospect.In this experiment,the consolidation properties and sulfate resistance of magnesia-activated slag(GGBS-MgO),calcium oxide-activated slag(GGBS-CaO)and cement(PC)were studied by appearance,unconfined compressive strength,mass change,the change of mineral composition and microstructure.The results show that slag activated by CaO obtains a higher pH value than MgO activated slag.Higher pH value is beneficial to the fracture of vitreous O-Si-O and O-Al-O bonds in slag,which causes a better consolidation characteristic as more hydration products.The unconfined compressive strength of sand samples stabilized by GGBS-MgO and GGBS-CaO increases 42.2%and 101.2%respectively after curing for 28 d.When the sand samples were immersed in 5wt%Na 2SO 4 solution for 150 d,sulfate ions react with calcium hydroxide to form ettringite and gypsum in PC,which results in more pores and obvious cracking.After 150 d of immersion,the unconfined compressive strength of PC is decreased to 0.41 MPa while the unconfined compressive strength of GGBS-MgO and GGBS-CaO continuously increases due to the formation of hydrotalcite.As a result of adsorption of sulfate ions by hydrotalcite,the sulfate resistance of GGBS-MgO and GGBS-CaO is better than PC.

关 键 词：化学固结 碱激发材料 固结砂 硫酸盐侵蚀 

分 类 号：TU528[建筑科学—建筑技术科学]