Study On Rheological Properties Of Manufactured Sand Mortar

With the rapid development of infrastructure and protection of environment, river sandresources are increasingly scarce,and more manufactured sand is used in concrete. Since thereare significant differences in shape, gradation, powder content between river sand andmanufactured sand,concrete with different sand exist many different performances,amone whichthe most important is work performance. Rheological parameters are important indicators tocharacterize flow properties and work performance of cement-based materials. It is of greatsignificance in guiding concrete engineering applications, controling performance of freshconcrete to ensure project quality. Therefore, Ithas important theoretical significance andpractical value to study work performance of concrete from rheological point of view.Summarize application of eheology in concrete: Application of bingham in concreteresearch, thixotropic and evaluation methods, physical structure of the cement slurry and freshconcrete, workability of concrete.Comparative rheological properties of manufactured sand and river sand mortar underdifferent water-cement ratio. The results show: Under the same w/c, compared with river sandmortar, manufactured sand mortar have larger yield stress,smaller plastic viscosity, greaterchange of rheological parameters over time amd smaller thixotropic; The larger water-cementratio is, the smaller the plastic viscosity and yield stress of river sand mortar and manufacturedsand mortar, the narrower the gap between the rheological parameters of two mortar,and thesmaller change of rheological parameters over time amd smaller the thixotropic is.Study on impact of fly ash, superplasticizer on the rheological properties of mortar. Theresults show: With the increase of fly ash, rheological parameters of mortar change decreasesover time, the finer the fly ash the more obvious effects; when fly ash content is less than15%,there are no significant effect.When fly ash content is more than15%, the fly ash with largefineness weaken the thixotropic of mortar, while fly ash with small fineness reinforced thethixotropic of mortar. When superplasticizer was added,the yield stress reduces, rheologicalparameters change over time increases, thixotropic reduces.Analysis grain shape characteristics of manufactured sand from the edges of angularity andmorphology,and analysis the relationship between gradation and angularity, specific surface areaof manufactured sand,impact of gradation and power content on the rheological properties ofmortar. The results show: With the changes of particle size and gradation, angularity of differentsand has consistent variation. With the reduction of particle size decreases the roundness ofmanufactured sand decreases. With gradation coarsen, Yield stress of three kinds ofmanufactured sand after the first decreases and then increases,while yield stress of river sanddecreases. Yield stress and angularity of limestone sand mortar have good correlation. Withgradation coarsen, Plastic viscosity four fine aggregate mortar decrease.There is good correlationbetween plastic viscosity and specific surface area of river sand and limestone sand mortar. Themore coarse the gradation is, the higher the allowable of power content.With powder contentincreases, the plastic viscosity of limestone sand mortar increases.