硅酸盐水泥-阳离子乳化沥青浆体的流变模型

Rheological Models for Portland Cement-Cationic Emulsified Asphalt Pastes

硅酸盐水泥--乳化沥青浆体的流变性决定了水泥乳化沥青砂浆的施工性能,并影响高速铁路板式无砟轨道砂浆充填层的施工质量和耐久性。采用P·II52.5R硅酸盐水泥和阳离子乳化沥青制备了不同配合比的硅酸盐水泥--阳离子乳化沥青(PC-CEA)浆体。在25℃用同轴旋转流变仪测量各种PC-CEA浆体的流变曲线。用不同流变模型拟合实测的PC-CEA浆体的剪切应力和剪切应变数据,分析了其流变行为和组成配比的关系。结果表明:PC-CEA浆体具有屈服应力和触变性,并主要呈剪切变稀行为;依据拟合良好性,Herschel-Bulkley模型最适合表征PC-CEA浆体流变性;由该模型拟合获得的PC-CEA浆体的屈服应力和稠度系数随浆体中水泥占浆体总体积分数(水泥体积分数)增加而增加,随着浆体中水泥和沥青颗粒的体积分数(固体体积分数)的减小而减小;当固体体积分数≤40%时,PC-CEA浆体出现剪切增稠行为。

The rheology of cement-emulsified asphalt paste plays a key role in the workability of cement-emulsified asphalt mortar,and controls the construction quality and durability of mortar layer in the slab track structure of high speed railways.In this paper,rheological modeling for Portland cement-cationic emulsified asphalt （PC-CEA） pastes was investigated.The effects of cement to asphalt in mass ratios,cement to paste in volume ratios and solid volume fractions on the rheology of pastes were analyzed according to the rheological curves measured by a rotating coaxial cylinder viscometer at 25 ℃.The rheological models were used to predict the data of shear stress and shear rate.The results indicate that the PC-CEA pastes have yield stress values and show a shear thinning behavior with a slight thixotropy.The Hereshel-Bulkley model is suitable for PC-CEA paste.The yield stress and the consistency increase with the increase of volume ratio of cement to paste,but with the decrease of solid volume fraction.The pastes show a shear thickening behavior when the solid volume fraction is ＜ 40％.