摘要
为了研究石灰石粉细度、掺量及浆体的静置时间对水泥(Cement,简称C)-石灰石粉(Limestone Powder,简称LP)浆体流变性能的影响,采用Anton Paar MCR 102型旋转流变仪,测试C-LP浆体中400目(LP1)和800目(LP2)LP对流变曲线的影响。采用Herachel-Bulkey(H-B)模型及Bingham模型拟合经时流变曲线得到浆体屈服应力、流变指数及塑性黏度等参数,并通过计算剪切测试下滞回环面积以表征浆体的触变性能。同时,通过Andreasen颗粒紧密堆积模型计算得出体系中颗粒分布模数,基于颗粒体积分数计算体系中固体颗粒总比表面积,并对体系水化放热过程进行分析,从而进一步解释石灰石粉不同细度、掺量及不同静置时间对浆体流变行为的影响机制。研究结果表明,随石灰石粉掺量或细度的增大,浆体体系中固体颗粒堆积密实程度增大;石灰石粉的细度比掺量对水泥水化放热的影响程度更大。增加LP1掺量,浆体屈服应力及塑性黏度下降;增加LP2掺量,浆体屈服应力及塑性黏度上升;静置时间的延长使浆体屈服应力及塑性黏度均增大;掺入适量(质量分数为20%~50%)LP1或LP2均对增强浆体屈服应力、塑性黏度及触变性有显著作用。从开始搅拌至90 min内,影响C-LP浆体流变参数的因素以颗粒的物理填充效应和分子间作用力为主。
In order to study the influences of fineness and amount of limestone powder as well as the standing time on the rheological properties of Cement(C)-Limestone Powder(LP) pastes, the Anton Paar MCR 102 rotary rheometer was used to test the effects of 400 mesh(LP400) and 800 mesh(LP800) on the rheological curves of CLP pastes. The parameters such as yield stress, rheological index and plastic viscosity of pastes were obtained by fitting the rheological curves with the Herachel-Bulkey(H-B) model and the Bingham model, and the hysteresis loop area was calculated to characterize the thixotropic properties of the pastes under shearing tests. Meanwhile,the distribution modulus in each system was calculated by the Andreasen’s close particle packing model, the total specific surface area of solid particles in each piece of pastes was calculated based on the volume fraction of particles, and the exothermic process of hydration of the system was analyzed to further explain the effect of different fineness of LP, amount of LP and standing time on the rheological behavior of the pastes. The results showed that with the increasing content or fineness of LP, the degree of solid particles accumulation in the pastes increased. The fineness of LP had greater effects on cement hydration than the amount. Therefore, as the amount of LP400 increased, the yield stress and plastic viscosity of the paste decreased, but the yield stress and plastic viscosity increased with increasing amount of LP800. The elongation of standing time increased the yield stress and plastic viscosity. Adding the appropriate amount(20%~50%) of LP400 or LP800 could enhance the yield stress, plastic viscosity and thixotropy of the paste. The rheological parameters of C-LP pastes were mainly affected by particle filling effect and intermolecular forces from the beginning of mixing to 90 min.
作者
冯恺雯
马昆林
龙广成
谢友均
曾晓辉
王春娥
FENG Kaiwen;MA Kunlin;LONG Guangcheng;XIE Youjun;ZENG Xiaohui;WANG Chun’e(School of Civil Engineering,Central South University,Changsha 410075,China;Changsha Building Energy Conservation and Green Building Industry Technology Innovation Strategic Alliance,Changsha 410011,China)
出处
《铁道科学与工程学报》
EI
CAS
CSCD
北大核心
2022年第4期966-975,共10页
Journal of Railway Science and Engineering
基金
长沙市科技计划重点研发项目(kh2005213)。
关键词
石灰石粉
水泥浆体
细度
流变性能
经时变化
limestone powder
cement pastes
fineness
rheological property
time-dependent
作者简介
通信作者:马昆林(1976−),男,云南昆明人,教授,博士,从事铁道工程材料研究,E−mail:makunlin@csu.edu.cn。
