Quantification of the shape of particles for calculating specific surface area of powders

Author(s): Yahya Ghasemi, Mats Emborg and Andrzej Cwirzen
Paper category: Proceedings of the International RILEM Conference Materials, Systems and Structures in Civil Engineering 2016 Segment on Fresh Concrete
Editor(s): Lars N. Thrane, Claus Pade, Oldrich Svec and Nicolas Roussel
ISBN: 978-2-35158-184-1
e-ISBN: 978-2-35158-185-8
Publisher: RILEM Publications SARL
Publication year: 2016
Pages: 42-51
Total Pages: 10
Language : English

Abstract: The concepts of particle packing and water/paste layer theories are commonly used for basis of concrete mix design models. While particle packing insists on achieving fewer voids in aggregate matrix by e.g. adding fine aggregates, water/paste layer theories state that increasing the amount of fines will lead to higher water demand since the specific surface area of particles will increase. In order to calculate the thickness of excess paste in water/paste layer theories, it is essential to have an estimation of specific surface area of the particles. However, the complexity of the instruments required to measure specific surface area makes the methods costly and also causes an issue regarding the availability of the instruments leading to less popularity of water/paste layer theories compared to mix design approaches based on the particle packing theory. Introducing a model that can roughly estimate the specific surface area of particles may eliminate the need for measuring specific surface area which in turn contributes to cost reduction and also laying a foundation for calculation of water layer thickness. The paper aimed to study calculated specific surface area by replacing regular convex polyhedrons with actual particle shapes based on the size distribution curves of the samples and to compare the results with data obtained by Blaine test. The conducted study suggests that in most cases, assumption of spherical shape for the particles leads to an acceptable estimation of SSA. However, SSA of powders with more angular particles can be calculated more accurately with the assumption of Polyhedron shape rather than spheres

Online publication : 2016
Publication type : full_text
Public price (Euros) : 0.00

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