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logo LGC logo LGC__Plant_growing_through_crack logo LGC__ECObes ECOBES
   
Contact Stéphanie Staquet, Ameur Hamani, Jérôme Carette
   
Keywords Early age, restrained shrinkage, desiccation, hydration, cracking, limestone filler, blast-furnace slag.
   
Collaborations Prof. Abdelkarim AÏT-MOKHTAR, LEPTIAB, University of La Rochelle, France.

Dr. Philippe TURCRY, LEPTIAB, University of La Rochelle, France.

Prof. Marie-Paule DELPLANCKE-OGLETREE, 4MAT, Université Libre de Bruxelles, Belgium.

   
Description of the research project  Concrete is the second most used resource in the world after water. Currently, there is no substitute material as durable as concrete for most practical applications in construction. However, one of the main constituent of concrete, namely clinker which is responsible for high CO2 emissions in the atmosphere from cement manufacture, can be partially substituted by additions: limestone filler (LF), fly ash (FA) and granulated blast-furnace slag (BFS), which are by-products of various industries. In addition to saving energy and preserving natural resources through the enhancement of co-products of various industries, mineral additions provide technical advantages especially in terms of workability, permeability, mechanical strength and durability.

For this project, the main objective is to investigate the material and structural behavior. The cracking risk of concrete in structural situations, made with high rates of clinker substitution by LF and BFS, is evaluated. Several experimental means will be used to understand the physico-chemo-mechanical behavior of the studied concretes at early ages. Indeed, if the isolated effect of each mineral addition is relatively well known, the effect of a combination of two mineral additions remains not very well understood.

The following experimental works are carried out: Restrained and free autogenous shrinkage (TSTM), tensile and compressive creep (TSTM), free autogenous shrinkage (BTJADE), setting time, Young modulus and Poisson coefficient (FreshCon), compressive and tensile strength, degree of hydration evolution (TGA + Isotherm Calorimetry), microstructure investigation (mercury porosimetry, XRD, SEM) in collaboration with M&M department, drying and moisture diffusion characterization (DVS) in collaboration with the LEPTIAB laboratory – University of La Rochelle.

Mechanical behavior of concrete structures with low clinker content will be reviewed with the aim to classify this type of concrete following a performances approach.

Another part of the project concerns the modeling of the microstructure evolution (Figure 1), the simulation of the hydration, the morphological properties and the chemical shrinkage of the studied concretes equivalent pastes.

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Anhydrous microstructure

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Hydrated microstructure

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Example of obtained results

Figure 1 - Modeling of the microstructure evolution

     
Selected publications [1] A. Darquennes, S. Staquet, M-P. Delplancke-Ogletree, B. Espion, Effect of autogenous deformation on the cracking risk of slag cement concretes, Cement & Concrete Composites 33(3), 368–379 (2011).

[2] A. Darquennes, M.I.A. Khokhar, E. Rozière, A. Loukili, F. Grondin, S. Staquet, Early age deformations of concrete with high content of mineral additions, Construction and Building Materials 25(4), 1836–1847 (2011).

[3] A. Darquennes, S. Staquet, B. Espion, Behaviour of slag cement concrete under restraint conditions, European Journal of Environnemental and Civil Engineering, Volume 15(5), 787-798 (2011).

[4] S. Staquet, C. Boulay, N. Robeyst, N. De Belie, Ultrasonic monitoring of setting and autogenous shrinkage development of high performance concrete, 8th International Conference on Creep, Shrinkage and Durability of Concrete and Concrete Structures, Ise-Shima, Japan, September 30th – October 2nd, Vol. 1, 321-327 (2008).