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logo LGC logo LGC__TSTM_rupture logo lgc__concrete_4 Effect of the rate of saturation of aggregate on concrete shrinkage
Contact Stéphanie Staquet, Rachid Cortas, Ameur El Amine Hamami
Keywords Early age, Shrinkage, Cracking, aggregates, water saturation rate.
Collaborations
Prof. Ahmed LOUKILI, GeM, Centrale Nantes, France.

Dr Emmanuel ROZIÈRE, GeM, Centrale Nantes, France.

François Cussigh, Vinci Construction, France

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

Description of the research project


Early age cracking of concrete is often observed in absence of mechanical loading. This has direct consequences on the material and structure durability. This cracking is usually induced by restrained deformations (thermal or shrinkage deformation). These deformations happen at early age and lead to more complex phenomena. Several existing model gives an estimation of the cracks locations in a concrete structure. Nevertheless, these models do not take into account several parameters which are determinant in the cracking process of concrete at early age.

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Figure 1 - Image  from a microscope scanning electron

To cope with this problem, this project proposes an experimental study of the composition effect on early age cracking of concrete. One is especially interested in the type and the water saturation rate of the aggregates, the type of cement and mineral additions. Four types of aggregates are studied (Beavillier, Boulonnais, Palvadeau, and lightweight limestone aggregate) with 3 saturation rates (0%, 50% and 100%).

The work here proposed is split in two parts. The first part (carried out at Centrale Nantes (CN), France) focuses on the study of shrinkage: plastic, volumetric, desiccation, autogenous and restrained (ring test). In addition to shrinkage, capillary depression is studied for all concretes.

The second part concerns the study of the early age concrete crackingcarried out at BATir, ULB. This study is mainly based on the use of a TSTM (Temperature Stress Testing Machine). This device allows studying the concrete behaviour since casting in free or partially/totally restrained condition. Additional experimental works are carried out: FreshCon (setting time, Young modulus and Poisson coefficient development), BTJADE (Free autogenous shrinkage in isothermal conditions), and Microstructure investigation (pore size distribution, SEM imaging and degree of hydration).

transparent square_100 BTJADE essai

Figure 2 - BTJADE device

   
Support
  • Bourse CIFRE - FNTP - Vinci Construction France.
   
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).