Silica source for formation of C-S-H in waste sediment-steel slag mixtures
May 27-June 1, 2018
Dredged soils, which results from marine and waterfront engineering work, are soft and unfavorable physical properties, and often landfilled as wastes. However, when it is mixed with alkali activating material, in this case steel slag, it develops strength by chemical reaction forming hydrates, resulting in cementation and developing strength. This mixture is awaited to be used for undersea constructions such as making reclamation in place of cement, but its utilization is limited due to the un-predictableness of the mixture’s strength development due to the variation in components of the steel slags and dredged soils. The cementation is hypothesized to be occurring by calcium silicate hydrate (C-S-H) formation (Kiso et al., 2008) by pozzolanic reaction, and calcium is stated to be supplied from Ca(OH)2, but especially the source of silica is not being clarified. Revealing the source and clarifying the effect of them to the formation of secondary hydrate phases quantitatively would enable to predict strength development of the mixture by simple steps of characterization of starting materials, which would enable the utilization of the wastes as construction resources.
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Kanako Toda, Tsubasa Otake, Tsutomu Sato, Haruna Sato, Nilan Weerakoon, and Satoshi Nishimura, "Silica source for formation of C-S-H in waste sediment-steel slag mixtures" in "International Conference on Alkali Activated Materials and Geopolymers: Versatile Materials Offering High Performance and Low Emissions", J. Provis, University of Sheffield C. Leonelli, Univ. of Modena and Reggio Emilia W. Kriven, Univ. of Illinois at Urbana-Champaign A. Boccaccini, Univ. of Erlangen-Nuremberg A. Van Riessen, Curtin University, Australia Eds, ECI Symposium Series, (2018). http://dc.engconfintl.org/geopolymers/50