Karen Scrivener

De nationalité anglaise, Karen Scrivener est née en 1958. Au cours de sa carrière, ses travaux et sa recherche traitaient des domaines suivants: Identification du développement microstucturale pendant l'hydratation du ciment. Elaboration d'une approche multitechnique pour étudier la microstucture des ciments et bétons, avec accent sur la quantification par analyse des images d'électrons retrodiffusés. Caractérisation de l'auréole de transition de la pâte de ciment autour des granulats. Compréhension des processus de dégardation des bétons, en particulier le gonflement lié à la formation de l'éttringite retardée dans les bétons étuvés.

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MSE-171: Materials

Une introduction à la science des matériaux appliquée aux matériaux de construction courants, en particulier le béton et les métaux. Description de leur fabrication, leurs comportements mécanique et thermique et leur utilisation en construction.

MSE-322: Building materials + Laboratory work

Science des matériaux de construction non métalliques les plus utilisés et plus particulièrement des matériaux cimentaires (béton). Composition chimique, fabrication et comportement sur la durée.

MSE-420: Cementitious materials (advanced)

Discussion of topical subjects related to the current use of cementitious materials. Through a guided literature survey prepare a presentation in a group on a topical issue

Ciment

vignette|Du ciment, fourni en sac, prêt à être mélangé avec de l’eau et des granulats. Le ciment est un liant hydraulique (qui durcit sous l'action de l'eau), utilisé dans la préparation du béton, et

Argile

L’argile est une matière rocheuse naturelle à base de silicates ou d'aluminosilicates hydratés de structure lamellaire, provenant en général de l'altération de silicates à charpente tridimensionnell

Béton de ciment

thumb|upright=1.0|Un mètre cube de béton (représentant la production mondiale annuelle de béton par habitant). Le béton de ciment, couramment appelé béton, est un mélange de ciment, de granulats, d'e

Characterisation and hydration kinetics of beta-C2S synthesised with K2SO4 as dopant

Shashank Bishnoi, Sreejith Krishnan, Karen Scrivener, Franco Alberto Zunino Sommariva

In this study, a protocol for synthesising beta-C2S using K2SO4 as a dopant has been reported. Quantitative X-Ray diffraction was used to characterise synthesised samples. It was observed that it is possible to synthesise beta-C2S with high purity (>96 wt%) and limit the formation of free lime to below 0.5 wt% using this protocol. Unreactive gamma-C2S was the main secondary phase present in the sintered samples. Isothermal calorimetry studies were conducted to understand the reaction kinetics which showed that beta-C2S reacts slowly but produces similar calorimetric curve profiles as that of C3S. The C-S-H formed from the hydration of C2S was observed to be morphologically and compositionally identical to the C-S-H produced from the hydration of C3S. The hydration kinetics of beta-C2S was seen to be affected by the presence of aluminosilicate pozzolan, such as calcined clay, which can have practical implications while producing blended cements with belitic clinkers.

PERGAMON-ELSEVIER SCIENCE LTD2023

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Does carbon footprint reduction impair mechanical properties and service life of concrete?

Diana Londoño Zuluaga, Karen Scrivener

The aim of this study is to evaluate how much the changes in the concrete mix design, which enable carbon footprint reduction, are impacting mechanical properties and predicted service life of concrete structure. The starting point of this study was concrete mix used in a recent reinforced concrete Peljesac Bridge in the Adriatic. In the first round of experiments the amount of cement in this initial mix was significantly lowered, without jeopardising workability of the mix. In the second round, the main part of the cement was substituted with the combination of fly ash and limestone or calcined clay and limestone. All supplementary cementitious materials used were sourced in the region of the structure. The calcined clays used in this study were collected locally and found to have a low kaolin content. On all mixes fresh and mechanical properties were tested to ensure that the requested equal or better workability and mechanical stability were reached. Furthermore, on each mix chloride migration was tested to evaluate the resistance of mix to chloride penetration. All mixtures were evaluated based on the overall performance considering mechanical, durability, and carbon footprints. The results indicate that the total cement content had a significant effect on durability and thus service life. The bridge mix design was determined to be 'over designed,' as all alternative mixes achieved a similar or higher sustainability index with lower amount of cement.

SPRINGER2023

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Influence of Low- to Medium-Kaolinite Clay on the Durability of Limestone Calcined Clay Cement (LC3) Concrete

Matea Flegar, Karen Scrivener

The kaolinite content is principally responsible for the durability performance of Limestone Calcined Clay Cement (LC3), which calls into question its global applicability. The clay supply has a significant impact on the LC3 system's reduced carbon footprint advantage. The influence of kaolinite concentration from two separate clays (collected in East South-East Europe) on the durability performance of concrete was investigated in this study. The low-kaolinitic clay had 18% kaolinite, while the medium-kaolinitic clay contained around 41% kaolinite. The compressive strength, chloride intrusion, electrical conductivity, surface resistivity, and sorptivity index were measured on concrete after 28 days. Furthermore, the pore structure development of these mixtures was investigated in relation to the kaolinite content of the mixtures. The reactivity test was performed on clays to measure their reactivity levels within the cementitious system. The results show that kaolinite content has a moderate effect on compressive strength, but it has a considerable effect on other durability indices. When compared to the Portland cement mixture, the chloride migration and diffusion coefficients were reduced by 50% and 36%, respectively, in the combination with a medium kaolinite content (more than 40%). The low-kaolinitic clay, on the other hand, achieved 60% of the chloride penetration resistance of the medium-kaolinitic clay. Furthermore, low-kaolinitic clay has been demonstrated to be suitable for low-carbon concrete in moderate exposure conditions.

MDPI2023

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