Print Email Facebook Twitter Basic properties of cement paste mixed with calcium hydroxide-ettringite composite type expansive additive Title Basic properties of cement paste mixed with calcium hydroxide-ettringite composite type expansive additive Author Handa, K. (Fujita Corporation) Ye, G. (TU Delft Materials and Environment) Contributor Ye, Guang (editor) Dong, Hua (editor) Liu, Jiaping (editor) Schlangen, Erik (editor) Miao, Changwen (editor) Date 2021 Abstract In this study, we targeted a calcium hydroxide and ettringite composite-type expansive additive (EA) and obtained the basic characteristics of the EA mixed cement paste in order to create a method for calculating volume expansion based on the hydration reaction of the PCEA system. Expansion strain, setting time, and compressive strength were measured. In addition, we observed the state of EA after hydration using a micro-CT scanner and scanning electron microscope, and elucidated the expansion mechanism. Our results show that strain rapidly increased and the compressive strength decreased when the replacement ratio of the EA (Crep) exceeds 6.4%. At the same time, radial cracks were generated from the hydrated EA particles, suggesting that the EA itself grew to expand the cement paste. Although no ettringite was confirmed inside the EA when the Crep was 5.1%, when the Crep was 10.3%, ettringite was formed vertically from the surface of C3A with a large amount of pores. These results show that simultaneous formation of ettringite and pores causes rapid expansion. Subject Expansive additiveCalcium hydroxideEttringitemicro-CT scanningSEM To reference this document use: http://resolver.tudelft.nl/uuid:bab94f86-b2cc-4da4-bb91-d28b089946f9 Publisher Delft University of Technology ISBN 978-94-6366-422-6 Source 4th International Rilem Conference on Microstructure Related Durability of Cementitious Composites: Microdurability 2020 Event 4th International Rilem Conference on Microstructure Related Durability of Cementitious Composites, 2021-04-29 → 2021-05-27, Online, Delft, Netherlands Part of collection Institutional Repository Document type conference paper Rights © 2021 K. Handa, G. Ye Files PDF Basic_properties_of_cemen ... ditive.pdf 1.22 MB Close viewer /islandora/object/uuid:bab94f86-b2cc-4da4-bb91-d28b089946f9/datastream/OBJ/view