Effet de l'utilisation d'ajouts cristallins sur le potentiel de cicatrisation de bétons à hautes performances en condition de service

RÉSUMÉ Les infrastructures nord-américaines en béton armé sont exposées à des conditions environnementales très sévères, causant des dégradations précoces en favorisant l’infiltration d’eau, de gaz et d’agents agressifs dans le béton. La pénétration de ces derniers est accélérée par la présence de fissures, puisqu’elles leur offrent un chemin préférentiel d’entrée. L’apparition de fissures au cours du cycle de vie d’une structure résulte de sollicitations d’origines internes (retrait, hydratation et fluage), externes (gradient de température, gradient d’humidité, attaque chimique) et mécaniques (charges mortes et vives).----------ABSTRACT North American reinforced concrete infrastructure is exposed to severe environmental conditions, causing precocious degradation by promoting the infiltration of water, gas and aggressive agents into the concrete. The penetration of the latter is accelerated by the presence of cracks, since they offer them a preferential path of entry. The emergence of cracks during the life cycle of a structure results from internal stresses (shrinkage, hydration and creep), external stresses (temperature gradient, gradient of humidity, chemical attack) and mechanical stresses (dead and live loads)

Evaluation of the Self-healing Capability of Ultra-High-Performance Fiber-Reinforced Concrete with Nano-Particles and Crystalline Admixtures by Means of Permeability

[EN] Self-healing is the capability of a material to repair its damage autonomously. Ultra-High-Performance Fiber Reinforced Concrete (UHPFRC) has potentially higher self-healing properties than conventional concrete because of its lower water/binder content and controlled microcracking due to the high fiber content. This work uses a novel methodology based on the permeability to evaluate autogenous self-healing of UHPFRC and enhanced self-healing, incorporating several additions. To this purpose, one UHPFRC was selected and modified to include alumina nanofibers in 0.25% by the cement weight, nanocellulose (nanocrystals and nanofibers), in a dosage of 0.15% by the cement weight, and 0.8-1.6% of a crystalline admixture. The results obtained show that the methodology proposed allows the evaluation of the self-healing capability of different families of concrete mixes that suffered a similar level of damage using permeability tests adapted to the specific properties of UHPFRC.The authors would like to acknowledge the European Union¿s Horizon 2020 ReSHEALience project (Grant Agreement No. 760824).Doostkami, H.; Roig-Flores, M.; Negrini, A.; Mezquida-Alcaraz, EJ.; Serna Ros, P. (2020). Evaluation of the Self-healing Capability of Ultra-High-Performance Fiber-Reinforced Concrete with Nano-Particles and Crystalline Admixtures by Means of Permeability. Springer. 489-499. https://doi.org/10.1007/978-3-030-58482-5_45489499Homma, D., Mihashi, H., Nishiwaki, T.: Self-healing capability of fibre reinforced cementitious composites. J. Adv. Concr. Technol. 7(2), 217–228 (2009)Maes, M., Snoeck, D., De Belie, N.: Chloride penetration in cracked mortar and the influence of autogenous crack healing. Constr. Build. Mater. 115, 114–124 (2016)Edvardsen, C.: Water Permeability and Autogenous Healing of Cracks in Concrete, vol. 96 (1999)De Belie, N., et al.: A review of self-healing concrete for damage management of structures. Adv. Mater. Interfaces 5(17) (2018)Wang, H.L., Dai, J.G., Sun, X.Y., Zhang, X.L.: Characteristics of concrete cracks and their influence on chloride penetration. Constr. Build. Mater. 107, 216–225 (2016)Wang, K., Jansen, D.C., Shah, S.P., Karr, A.F.: Permeability study of cracked concrete. Cem. Concr. Res. (1997)Šavija, B., Schlangen, E.: Autogeneous healing and chloride ingress in cracked concrete. Heron 61(1), 15–32 (2016)Ismail, M., Toumi, A., François, R., Gagné, R.: Effect of crack opening on the local diffusion of chloride in cracked mortar samples. Cem. Concr. Res. 38(8–9), 1106–1111 (2008)Habel, K., Gauvreau, P.: Response of ultra-high performance fiber reinforced concrete (UHPFRC) to impact and static loading. Cem. Concr. Compos. 30(10), 938–946 (2008)Denarié, E., Brühwiler, E.: Strain-hardening ultra-high performance fibre reinforced concrete: deformability versus strength optimization. Restor. Build. Monum. 17(6), 397–410 (2014)Granger, S., Pijaudier-Cabot, G., Loukili, A.: Mechanical behavior of self-healed ultra high performance concrete: from experimental evidence to modeling. In: Proceedings of the 6th International Conference on Fracture Mechanics of Concrete and Concrete Structures, vol. 3, pp. 1827–1834 (2007)Escoffres, P., Desmettre, C., Charron, J.P.: Effect of a crystalline admixture on the self-healing capability of high-performance fiber reinforced concretes in service conditions. Constr. Build. Mater. 173, 763–774 (2018)Sisomphon, K., Copuroglu, O., Koenders, E.A.B.: Self-healing of surface cracks in mortars with expansive additive and crystalline additive. Cem. Concr. Compos. 34(4), 566–574 (2012)Roig-Flores, M., Moscato, S., Serna, P., Ferrara, L.: Self-healing capability of concrete with crystalline admixtures in different environments. Constr. Build. Mater. 86, 1–11 (2015)Roig-Flores, M., Pirritano, F., Serna, P., Ferrara, L.: Effect of crystalline admixtures on the self-healing capability of early-age concrete studied by means of permeability and crack closing tests. Constr. Build. Mater. 114, 447–457 (2016)Ferrara, L., Krelani, V., Carsana, M.: A ‘fracture testing’ based approach to assess crack healing of concrete with and without crystalline admixtures. Constr. Build. Mater. 68, 535–551 (2014)Ferrara, L., Krelani, V., Moretti, F.: On the use of crystalline admixtures in cement based construction materials: from porosity reducers to promoters of self healing. Smart Mater. Struct. 25(8), 1–17 (2016)Cuenca, E., Cislaghi, G., Puricelli, M., Ferrara, L.: Influence of self-healing stimulated via crystalline admixtures on chloride penetration. In: America Concrete Institute, vol. 2018(SP 326), pp. 1–10. ACI Spec. Publ. (2018)Borg, R.P., Cuenca, E., Gastaldo Brac, E.M., Ferrara, L.: Crack sealing capacity in chloride-rich environments of mortars containing different cement substitutes and crystalline admixtures. J. Sustain. Cem. Mater. 7(3), 141–159 (2018)López, J.Á., Serna, P., Navarro-Gregori, J., Camacho, E.: An inverse analysis method based on deflection to curvature transformation to determine the tensile properties of UHPFRC. Mater. Struct. 48(11), 3703–3718 (2014). https://doi.org/10.1617/s11527-014-0434-0López, J.Á.: Characterisation of the Tensile Behaviour of UHPFRC By Means of Four-Point Bending Tests, March 2017Negrini, A., Roig-Flores, M., Mezquida-Alcaraz, E.J., Ferrara, L., Serna, P.: Effect of crack pattern on the self-healing capability in traditional, HPC and UHPFRC concretes measured by water and chloride permeability. In: MATEC Web Conference, vol. 289, p. 01006 (2019