纳米二氧化硅对高流态矿渣-脱硫石膏复合碱激发材料早期强度的影响机理  

Influence Mchanism of Nano-silica on the Early-strength of High-fluidity Slag and Desulfurization Gypsum Composite Alkali Activated Material

作　　者：臧晓雨 陈梦章 苗益祯 赵震阳 吴志昊 任皎龙 赵洪波 ZANG Xiao-yu;CHEN Meng-zhang;MIAO Yi-zhen;ZHAO Zhen-yang;WU Zhi-hao;REN Jiao-long;ZHAO Hong-bo(School of Civil and Engineering,Shandong University of Technology,Zibo 255000,China)

机构地区：[1]山东理工大学建筑工程与空间信息学院,淄博255000

出　　处：《科学技术与工程》2024年第23期10015-10021,共7页Science Technology and Engineering

基　　金：国家自然科学基金(42377174);山东省自然科学基金(ZR2022ME198)。

摘　　要：以矿渣和脱硫石膏为前驱体的高流态复合碱激发材料(high-fluidity slag and desulfurization gypsum composite alkali activated material,HSD-AAM)是目前构筑物修复与加固工程中常用的新型建筑材料之一。为了保证流动性,HSD-AAM通常采用较高的水胶比,影响了其早期强度,从而限制了HSD-AAM的应用。针对这一问题,通过室内试验研究了纳米二氧化硅(nano-silica,NS)掺量对HSD-AAM凝结时间、流动性、抗折和抗压强度(1、3、7 d)的影响,以期在不影响HSD-AAM流动性的前提下提升其早期强度;进而,通过扫描电子显微镜(scanning electronic microscopy,SEM)、X射线衍射(X-ray diffraction,XRD)和热重-差示扫描量热仪(thermogravimetric analysis and differential scanning calorimetry,TG-DSC)等方法分析了不同类型HSD-AAM的水化产物和微观结构,揭示了NS掺量对HSD-AAM早期强度的增强机理。结果表明:随着NS掺量的增加,HSD-AAM流动性降低且凝结时间缩短,而早期强度明显提升。NS掺量在0~3%之间时,每提升1%,HSD-AAM流动性平均降低6.0%;初凝和终凝时间平均缩短13.7%和10.0%;1 d抗折强度和抗压强度平均提升10.7%和20.2%;3 d抗折强度和抗压强度平均提升23.3%和12.4%;7 d抗折强度和抗压强度平均提升11.1%和32.9%。这是由于NS具有较高的火山灰活性,在早期与浆体内的Ca(OH)2发生水化反应,促进其水化进程,生成大量的C-S-H凝胶,改善了浆体结构疏松的特点,使浆体早期微观结构更加致密。The high-fluidity slag and desulphurization gypsum composite alkali material with(HSD-AAM)as precursors is one of the new building materials commonly used in the restoration and reinforcement of structures.In order to ensure fluidity,HSD-AAM usually uses a high water-binder ratio,which affects its early strength and thus limits the application of HSD-AAM.To solve this problem,the impact of the amount of nano-silica(NS)on the fluidity,setting time,flexural strength and compressive strength(1d,3d,7d)of HSD-AAM were studied through laboratory experiments,in order to improve the early strength of HSD-AAM without affecting its fluidity;Furthermore,thermogravimetric analysis and differential scanning calorimetry(TG-DSC),X-ray diffraction(XRD),and scanning electronic microscopy(SEM)were used to examine the hydration products and microstructure of the various varieties of HSD-AAM,the mechanism of enhancing the early strength of HSD-AAM by NS content was revealed.The results show that with the increase of NS content,the fluidity and setting time of HSD-AAM decrease,while the early strength increase significantly.When NS content is between 0 and 3%,the fluidity of HSD-AAM decreases by an average of 6.0%with each increase of 1%;the initial and final setting times shorten by 13.7%and 10.0%respectively;1 d flexural strength and compressive strength increase by 10.7%and 20.2%on average;3 d flexural strength and compressive strength increase by 23.3%and 12.4%on average;7 d flexural strength and compressive strength increase by 11.1%and 32.9%on average.This is due to the high pozzolash activity of NS and the hydration reaction with Ca(OH)2 in the slurry in the early stage,which promotes the hydration process and generates a large amount of C-S-H gel,which improves the loose structure of the slurry and makes the microstructure of the slurry more dense in the early stage.

关 键 词：碱激发材料 矿渣 脱硫石膏 纳米二氧化硅 早期强度 增强机理 

分 类 号：TU526[建筑科学—建筑技术科学]