Effect of Lignosulfonates on the Morphology of Calcium Hydroxide Crystals

Pesce, Cecilia, Pesce, Giovanni and Richardson, Alan (2020) Effect of Lignosulfonates on the Morphology of Calcium Hydroxide Crystals. In: 40th Cement and Concrete Science Conference. RILEM, Paris. (In Press)

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Abstract

Lignosulfonates is commonly used in concrete as superplasticisers. Its presence can affect crystallisation and carbonation kinetics of calcium hydroxide (CH), which is an important phase in hydrated cement since it plays a crucial role in the durability and performance of concrete. In this work, lime pastes were produced by slaking quicklime in distilled water. Ca lignosulfonate (CaLS) was added to them, either before and after the slaking process to investigate the effects of temperature on the CaLS-CH interaction. All samples were characterised at 0 and 6 months from slaking with the aim of investigating the effects of CaLS on CH crystallisation. Scanning electron microscopy and X-ray diffraction were used to investigate CH crystal size and morphology, whereas micro-chemical analyses contributed to the investigation of the chemistry of pore solutions. Results suggest that the addition of CaLS (both, during and after slaking) affects the CH crystals habit and size, which, in turn, can have an effect on the reactivity of CH and, consequently, on the properties of fresh and hardened concrete.

Item Type: Book Section
Subjects: F200 Materials Science
Department: Faculties > Engineering and Environment > Architecture and Built Environment
Faculties > Engineering and Environment > Mechanical and Construction Engineering
Depositing User: John Coen
Date Deposited: 02 Nov 2020 10:10
Last Modified: 02 Nov 2020 10:15
URI: http://nrl.northumbria.ac.uk/id/eprint/44657

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