低水胶比水泥浆体静动态流变行为的经时变化  

Time-dependent Static and Dynamic Rheological Behavior of Cement Paste with Low Water-Cement Ratio

作　　者：陈翠翠 张倩倩 杨勇 舒鑫 冉千平 CHEN Cuicui;ZHANG Qianqian;YANG Yong;SHU Xin;RAN Qianping(State Key Laboratory of High Performance Civil Engineering Materials,Nanjing 211103,China;Jiangsu Sobute New Materials Co.,Ltd.,Nanjing 211103,China;School of Materials Science and Engineering,Southeast University,Nanjing 210096,China)

机构地区：[1]高性能土木工程材料国家重点实验室,南京211103 [2]江苏苏博特新材料股份有限公司,南京211103 [3]东南大学材料科学与工程学院,南京210096

出　　处：《材料导报》2024年第15期168-172,共5页Materials Reports

基　　金：国家重点研发计划项目(2021YFB2601002);江苏省自然科学基金(BK20201075)。

摘　　要：基于浆体流动度、静态屈服应力以及小振幅振荡模式下储能模量,研究不同水胶比以及减水剂用量对浆体静动态流变行为经时变化的影响机制,探讨低水胶比浆体的静动态流变行为。研究结果表明:通过调整减水剂用量获得的初始流动度相同但水胶比不同的浆体,流动性经时变化存在显著的差异。极低水胶比浆体的流动性经时损失更为显著;但高减水剂用量时,浆体的流动性经时损失较小。基于静态屈服应力和储能模量G′表征了浆体静态流变行为的发展,发现颗粒胶体作用力和水化产物的桥接作用共同决定了浆体微观结构强度发展。低水胶比浆体的静态屈服应力和储能模量随时间延长增长更加显著。增加减水剂用量,可增大颗粒间距,抑制早期水化,有利于延缓颗粒网络强度发展。影响静动态流变行为内在机制的不同导致了浆体的静动态性能经时变化存在显著差异,其中水化产物的桥接作用是关键因素。Based on the flow spread,static yield stress,and small amplitude oscillatory shear test,the influence of water-cement ratio and the dosage of superplasticizer on the time-dependent rheological behavior of cement paste was studied,and the rheological behavior of cement paste with low water-cement ratio was discussed.The results show that there were significant differences in the time-dependent flow behavior of paste with the same initial flow spread but different superplasticizer dosage.The loss of fluidity over time of paste with an extremely low water-cement ratio was more significant,but could be largely reduced as more superplasticizer was added.Based on static yield stress and the storage modulus G’,the evolution of the static rheological behavior of paste could be characterized.It was found that the colloidal surface interactions and the bridging effect of the hydration product determine the strength development of particle network.The static yield stress and storage modulus paste with low water-cement ratio increase significantly with time.Increasing the dosage of superplasticizer could increase the particle spacing,and inhibit the early hydration of cement,which was helpful to delay the development of particle network.It is believed that the differences in the underlying mechanism that affect static and dynamic rheological behavior lead to different evolution of static and dynamic rheological behavior with time,in which the bridging effect of hydration products is a key factor.

关 键 词：水泥浆体 低水胶比 动态屈服应力 静态屈服应力 储能模量 

分 类 号：TU528[建筑科学—建筑技术科学]