再生细骨料碳化改性及其对砂浆流变性的影响  

Carbonation Modification of Recycled Fine Aggregate and Its Effect on Rheological Properties of Mortar

作　　者：肖建庄[1] 邓琪 段珍华 侯少丹 陶洁琳 XIAO Jianzhuang;DENG Qi;DUAN Zhenhua;HOU Shaodan;TAO Jielin(College of Civil Engineering,Tongji University,Shanghai,200092 China;College of Civil Engineering,Shaoxing University,Shaoxing,312000 China)

机构地区：[1]同济大学土木工程学院,上海200092 [2]绍兴文理学院土木工程学院,浙江绍兴312000

出　　处：《应用基础与工程科学学报》2024年第5期1486-1495,共10页Journal of Basic Science and Engineering

基　　金：国家自然科学基金项目(52078358,52178244);陕西省创新能力支撑计划资助(2023-CX-TD-41)。

摘　　要：再生细骨料(RFA)表面附着大量老砂浆,导致其吸水率和吸水速率均较高,严重影响所制备混凝土的工作性能与硬化性能.研究标准碳化和Ca(OH)2预喷洒后再碳化(CH碳化)对RFA品质的影响,旨在揭示取代率与碳化方式对再生砂浆(RM)流变性能的影响机理.结果表明:RFA的吸水时变行为与新拌RM的动态屈服应力和塑性黏度密切相关,可作为评价RFA品质的重要指标.随RFA取代率的提高,新拌砂浆动态屈服应力降低,30min内塑性黏度增长率提高显著;碳化能提升RFA的品质,改善所制备RM的流变性.相对标准碳化,CH碳化后RM的动态屈服应力与塑性黏度在30min时分别降低26.6%、25.1%,其动态屈服应力与塑性黏度30min内的增长率分别降低50.0%、83.5%;碳化改性后RM的抗压强度和抗折强度均得以提升.Recycled fine aggregate(RFA)seriously affects the fresh and hardening properties of concrete due to the presence of attached old mortar.The purpose of this study is to reveal the influence of replacement rate and carbonation methods on the rheological properties of recycled mortar(RM),where standard carbonation and carbonation after limewater spraying process(CH carbonation)were adopted to modify the quality of RFA,respectively.The results show that the dynamic yield stress and plastic viscosity of mortar were closely related to the time variation of water absorption,which exhibits a good effect on predicting the quality of RFA.As the replacement rate of RFA increases,the dynamic yield stress of fresh mortar decreases and the growth rate of plastic viscosity increases significantly within 30min.Both the two carbonation methods can improve the quality of RFA and the rheological properties of RM.Compared with standard carbonation,the dynamic yield stress and plastic viscosity of RM after CH carbonation decreased by 26.6%and 25.1%respectively at 30min,and their growth rates decreased by 50.0%and 83.5%within 30min,respectively.In addition,the compressive and flexural strengths of RM were both improved after carbonation modification.

关 键 词：再生砂浆 再生细骨料 碳化改性 吸水时变 流变性 

分 类 号：TU578.1[建筑科学—建筑技术科学]