Study of creep and shrinkage of self-compacting concrete-based natural pozzolana and Algerian siliceous fines

The use of natural Algerian fine as a mineral addition in self-compacting concrete (SCC) is a way of ecological and economic exploitation of these materials. An experimental program was established to study the fresh state behaviour and the instantaneous and long-term mechanical behaviours of three self-compacting specimens with the same mix proportions. Only the nature of their mineral additions was different. The study of SCC fresh properties shows compliance with the Association francaise de genie civil (AFGC) recommendations. The higher compressive strengths of concrete with pozzolanic and siliceous fines reveal a pozzolanic effect of these materials. The delayed deformations of the SCC made with Algerian fine and with limestone filler are quite similar. The comparison with the behaviour of an equivalent strength vibrated concrete shows a slightly higher deformability of SCC. Finally, the comparison with Eurocode 2 model predictions reveals an underestimation of the amplitudes of delayed strains.Original Abstract: L'incorporation de fines naturelles algeriennes en tant qu'addition minerale dans les betons autoplacants (BAP) constitue une voie de valorisation ecologique et economique. Un programme experimental a ete etabli afin d'etudier les comportements mecanique, instantane et differe, de trois betons autoplacants de meme formulation et ne differant que par la nature des additions minerales. L'etude de ces betons a l'etat frais montre un respect des recommandations de l'Association francaise de genie civil (AFGC). Les resistances mecaniques en compression superieures en presence de pouzzolanes naturelles et fines siliceuses. Les deformations differees des BAP formules avec fines algeriennes sont globalement du meme ordre de grandeur que celle du BAP avec filler calcaire. La comparaison avec des deformations differees sous charge en mode dessiccation d'un beton vibre de classe de resistance proche montre une deformabilite legerement plus forte des BAP. Enfin, la confrontation avec les predictions du modele Eurocode 2 revele une sous-estimation des amplitudes des deformations differees.