Effects of Superplasticizers in Highly Alkaline Model Suspensions Containing Silica Fume

"SP-178: Sixth CANMET/ACI/JCI Conference: FLy Ash, Silica Fume, Slag & Natural Pozzolans in Concrete" Pub Date : 1998-06-01 DOI:10.14359/6015

R. Flatt, Y. F. Houst, P. Bowen, H. Hofmann, J. Widmer, U. Sulser, U. Mäder, T. A. Bürge

{"title":"Effects of Superplasticizers in Highly Alkaline Model Suspensions Containing Silica Fume","authors":"R. Flatt, Y. F. Houst, P. Bowen, H. Hofmann, J. Widmer, U. Sulser, U. Mäder, T. A. Bürge","doi":"10.14359/6015","DOIUrl":null,"url":null,"abstract":"Synopsis: The behavior of superplasticizers has been studied in highly alkaline suspensions of magnesium hydroxide and silica fume, which can be considered as good model system for cementitious systems containing silica fume. Rheology showed that as superplasticizer dosage is increased, suspensions pass from behaving as Bingham fluids to Newtonian fluids. Beyond a critical concentration large dispersed particles sediment due to the absence of yield stress. The critical concentrations required to obtain Newtonian fluids has allowed to elucidate the dependence between adsorption and dispersion. Indeed, dispersion appears to be only linked to adsorbed polymers and can therefore be attributed either to electrostatic or steric repulsion mechanisms. On the other hand, superplasticizer requirement increases with silica fume fraction in particular with the less ionic polymer. This indicates important electrostatic interactions with the surface in the process of adsorption.","PeriodicalId":425482,"journal":{"name":"\"SP-178: Sixth CANMET/ACI/JCI Conference: FLy Ash, Silica Fume, Slag & Natural Pozzolans in Concrete\"","volume":"10 1","pages":"0"},"PeriodicalIF":0.0000,"publicationDate":"1998-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"15","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"\"SP-178: Sixth CANMET/ACI/JCI Conference: FLy Ash, Silica Fume, Slag & Natural Pozzolans in Concrete\"","FirstCategoryId":"1085","ListUrlMain":"https://doi.org/10.14359/6015","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"","JCRName":"","Score":null,"Total":0}

引用次数: 15

Abstract

Synopsis: The behavior of superplasticizers has been studied in highly alkaline suspensions of magnesium hydroxide and silica fume, which can be considered as good model system for cementitious systems containing silica fume. Rheology showed that as superplasticizer dosage is increased, suspensions pass from behaving as Bingham fluids to Newtonian fluids. Beyond a critical concentration large dispersed particles sediment due to the absence of yield stress. The critical concentrations required to obtain Newtonian fluids has allowed to elucidate the dependence between adsorption and dispersion. Indeed, dispersion appears to be only linked to adsorbed polymers and can therefore be attributed either to electrostatic or steric repulsion mechanisms. On the other hand, superplasticizer requirement increases with silica fume fraction in particular with the less ionic polymer. This indicates important electrostatic interactions with the surface in the process of adsorption.

查看原文本刊更多论文

高效减水剂对含硅粉高碱性悬浮液的影响

摘要:研究了高效减水剂在高碱性氢氧化镁和硅灰悬浮液中的行为，该悬浮液可被认为是含硅灰胶凝体系的良好模型体系。流变学研究表明，随着高效减水剂用量的增加，悬浮液由宾汉流体转变为牛顿流体。超过临界浓度，由于没有屈服应力，大量分散的颗粒沉积。获得牛顿流体所需的临界浓度已经允许阐明吸附和分散之间的依赖关系。事实上，分散似乎只与吸附的聚合物有关，因此可以归因于静电或空间排斥机制。另一方面，高效减水剂的需求随着硅灰分数的增加而增加，特别是随着离子聚合物的减少。这表明在吸附过程中与表面有重要的静电相互作用。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

求助全文

约1分钟内获得全文求助全文

来源期刊

"SP-178: Sixth CANMET/ACI/JCI Conference: FLy Ash, Silica Fume, Slag & Natural Pozzolans in Concrete"

自引率

0.00%

发文量