title: Cryo-FIB-nanotomography for quantitative analysis of particle structures in cement suspensions.
abstract: Cryo-FIB-nanotomography is a novel high-resolution 3D-microscopy technique, which opens new possibilities for the quantitative microstructural analysis of complex suspensions. In this paper, we describe the microstructural changes associated with dissolution and precipitation processes occurring in a fresh cement paste, which has high alumina and sulphate contents. During the first 6 min, precipitation of ettringite leads to a general decrease of the particle size distribution. In the unhydrated cement paste almost no particles smaller than 500 nm are present, whereas after 6 min this size class already represents 9 vol%. The precipitation of ettringite also leads to a significant increase of the particle number density from 0.294*10(9)/mm(3) at t(0min) to 20.55*10(9)/mm(3) at t(6min). Correspondingly the surface area increases from 0.75 m(2)/g at t(0min) to 2.13 m(2)/g at t(6min). The small ettringite particles tend to form agglomerates, which strongly influence the rheological properties. The particular strength of cryo-FIB-nt is the potential to quantify particle structures in suspension and thereby also to describe higher-order topological features such as the particle-particle interfaces, which is important for the study of agglomeration processes.
authors.affiliation: EMPA, Materials Science and Technology, 3D-Mat group, Ueberlandstr. 129, CH-8600 Dübendorf, Switzerland. lorenz.holzer@empa.ch
authors.forename: L
authors.initials: L
authors.lastname: Holzer
authors.forename: P H
authors.initials: PH
authors.lastname: Gasser
authors.forename: A
authors.initials: A
authors.lastname: Kaech
authors.forename: M
authors.initials: M
authors.lastname: Wegmann
authors.forename: A
authors.initials: A
authors.lastname: Zingg
authors.forename: R
authors.initials: R
authors.lastname: Wepf
authors.forename: B
authors.initials: B
authors.lastname: Muench