层状双氢氧化物改善地聚物抗氯离子渗透性能研究

本文提出利用经煅烧处理的层状双氢氧化物(LDHs)材料的阴离子交换与结构重建特性改善地聚物抗氯离子渗透性能。借助XRD与TEM分析表征了层状双氢氧化物经煅烧和氯离子插层后组成和结构的变化,采用电位滴定仪测试了NaCl溶液浸泡后地聚物样品距表面不同深度处的氯离子浓度演变规律,并通过SEM与MIP研究了煅烧处理的层状双氢氧化物对地聚物微结构的影响。结果表明:层状双氢氧化物经煅烧处理后在NaCl溶液中可通过吸附Cl-实现层状结构复原。煅烧处理的层状双氢氧化物可以提高地聚物的抗氯离子渗透性能,其3%的掺量可以减少地聚物氯离子渗透量44%,且有利于地聚物形成密实的浆体结构。

Improved Chloride Ion Penetration Resistance of Geopolymer by Adding Calcined Layered Double Hydroxides

The present work developed a new approach to improve the chloride ion penetration resistance of geopolymer based on ion-exchange and structure regeneration of the calcined layered double hydroxides (LDHs).XRD and TEM analyses were used to characterize the changes in composition and structure of LDHs which experienced calcination and Cl- intercalation.A potentiometric titrant was employed to measure the concentration variation of chloride ions at different depths to the geopolymer specimen surface af-ter immersion test in NaCl solution.The effect of calcined LDHs on the microstructures of geopolymer was investigated by SEM and MIP.The experimental results show that after reaction with saturated NaCl solution,the dispersed and layered structure is redisco-vered,which exhibits the structure regeneration of calcined LDHs by means of Cl- adsorption.The chloride ion concentration profile demonstrates the improved chloride ion penetration resistance which can be attributed to the addition of calcined LDHs,as 3％ cal-cined LDHs reduces the chloride ion concentration by nearly 44％.Meanwhile,we also observed a denser microstructure in the cal-cined-LDHs-contained geopolymer specimen.