Eine Plattform für die Wissenschaft: Bauingenieurwesen, Architektur und Urbanistik
Eine Plattform für die Wissenschaft: Bauingenieurwesen, Architektur und Urbanistik
Using atomic force microscopy to evaluate superplasticizers
Recent concretes like UHPC (ultra-high performance concrete) can comprise large quantities of fines to fill the voids between coarser particles like the cement and displace water which positively influences the flowability. Together with a very low water-binder ratio of about 0.20, the density of the formed matrix prevents the migration of corrosive agents like chloride ions and results in compressive and tensile strength that supersedes that of traditional concrete by far As the rheological properties of these fresh concretes depend mainly on the forces acting between the fines due to their high specific surface area, understanding of these forces has become crucial. At the University of Kassel, atomic force microscopy technique of colloidal probes have been used to study these forces, focusing on silica because these exhibit the largest fraction of inner surface in common UHPC mixtures. During these measurements, two individual silica particles were submerged in electrolyte solutions with added superplasticizer where they were approached and retracted from each other. The sum of the resulting forces that act between the particles while they were close could be measured with an accuracy of few nano-Newton. Using this technique and silica particles as a model system, several commercial superplasticizers could be evaluated regarding their influence on the mterparticle forces and the range of interaction.
Using atomic force microscopy to evaluate superplasticizers
Recent concretes like UHPC (ultra-high performance concrete) can comprise large quantities of fines to fill the voids between coarser particles like the cement and displace water which positively influences the flowability. Together with a very low water-binder ratio of about 0.20, the density of the formed matrix prevents the migration of corrosive agents like chloride ions and results in compressive and tensile strength that supersedes that of traditional concrete by far As the rheological properties of these fresh concretes depend mainly on the forces acting between the fines due to their high specific surface area, understanding of these forces has become crucial. At the University of Kassel, atomic force microscopy technique of colloidal probes have been used to study these forces, focusing on silica because these exhibit the largest fraction of inner surface in common UHPC mixtures. During these measurements, two individual silica particles were submerged in electrolyte solutions with added superplasticizer where they were approached and retracted from each other. The sum of the resulting forces that act between the particles while they were close could be measured with an accuracy of few nano-Newton. Using this technique and silica particles as a model system, several commercial superplasticizers could be evaluated regarding their influence on the mterparticle forces and the range of interaction.
Using atomic force microscopy to evaluate superplasticizers
Glotzbach, Christoph (Autor:in) / Stephan, Dietmar (Autor:in) / Schmidt, Michael (Autor:in)
2012
8 Seiten, 4 Bilder, 3 Tabellen, 9 Quellen
Aufsatz (Konferenz)
Englisch
| Elsevier | 1980
| TIBKAT | 1979
Towards Tailored Superplasticizers
| British Library Conference Proceedings | 2005
| NTIS | 1979