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Calcined dredged sediments as supplementary cementitious materials: properties and pozzolanic reactivity

Author(s): Ruben Snellings, Liesbeth Horckmans, Pawel Durdzinski, Céline Van Bunderen, Lucie Vandewalle, Koenraad Van Balen, Joris Dockx, Jos Vandekeybus, Özlem Cizer
Paper category: Proceedings
Book title: Proceedings of the International RILEM Conference
Materials, Systems and Structures in Civil Engineering 2016
Segment on Concrete with Supplementary Cementitious Materials
Editor(s): Ole M. Jensen, Konstantin Kovler and Nele De Belie
e-ISBN: 978-2-35158-179-7
Publisher: RILEM Publications SARL
Publication year: 2016
Pages: 218-225
Total Pages: 8
Language : English

Abstract: Dredging of ports, harbours and waterways generates large amounts of sediments that find few applications and need to be disposed of. The dredging sediments in this study originated from the port of Antwerp, contained mainly SiO2, CaO, Al2O3 and Fe2O3 and comprised as major mineral phases clays (2:1 clays and kaolinite), quartz, calcite and an amorphous phase.Sulfur and chloride contents were relatively low. Flash calcination at 820, 865 and 905°C reduced the total organic carbon fraction but did not alter the content of chloride and sulfate. The calcination treatment resulted in the dehydroxylation of the clay minerals and partial decarbonation of the calcite. Part of the CaO released in the decomposition of the calcium carbonates reacted with the dehydroxylated clays to form an amorphous, partially vitrified calcium-aluminosilicate reactive phase. Melt formation and sintering were more extensive at higher calcination temperatures (865 and 905°C); however this did not change the particle size distribution significantly, but did lead to a remarkable reduction in the BET specific surface area and related particle surface roughness. The calcined dredging sediments showed a pozzolanic reactivity superior to that of Class F fly ash as demonstrated in a lime reactivity test by isothermal conduction calorimetry. The reactivity test clearly demonstrates the elevated potential of calcined dredged sediments as a new pozzolanic SCM for the production of low–CO2 blended cements.

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

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