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Matériaux et Construction

, Volume 7, Issue 3, pp 191–196 | Cite as

The tensile creep and fracture of desiccated concrete and mortar on water sorption

  • D. J. Cook
  • M. N. Haque
Article

Abstract

The dynamic effects of water sorption on the strength reduction and the tensile creep of concrete and mortar are investigated. Moisture assisted crack growth is the major mechanism of tensile creep and/or, fracture of the desiccated material. Mechanisms of compressive creep of desiccated concrete on re-saturation with water, are discussed and compared with those of tensile creep.

Keywords

Tensile Strength Creep Strain Strength Reduction Water Sorption Splitting Tensile Strength 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

Résumé

On a étudié les effets dynamiques d'une sorption d'eau sur la diminution de la résistance et le fluage en traction de bétons et de mortiers. La recherche qu'on décrit ici indique que les processus de re-hydratation et de recrystallisation du gel de ciment lors d'une adsorption d'eau déterminent une microfissuration ou la propagation de fissures. On montre que la résistance en traction et le fluage en traction sont extrêmement sensibles aux microfissurations préexistantes, provoquées par la sorption, engendrées par la charge. On examine les mécanismes de fluage en compression du béton séché que l'on resature d'eau et on les compare avec ceux du fluage en compression dans des conditions ordinaires.

Les éprouvettes de béton et de mortier (102×102×508 mm) ont été séchées à l'étuve jusqu' à un poids constant, chargées à différents niveaux de contrainte (de 0,55 de la charge ultime jusqu' à 0,15), puis placées dans une chambre humide (94±3% H.R.), où l'on a également placé, après dessication à poids constant, des prismes de traction (102×102×508 mm) pour la détermination de la résistance en traction directe et des cylindres (15×75 mm de diamètre) pour les essais en compression et de traction par fendage.

Les éprouvettes de mortier, dont la forte teneur volumétrique en pâte de ciment est de 0,69, révèlent une diminution de 80% de la résistance en traction lors de la resaturation, tandis que la diminution de la résistance en compression est de l'ordre de 30%. Du fait de la diminution de la résistance en fonction du temps, de la réhydratation et de la forte microfissuration qui en résulte, les éprouvettes de mortier et de ciment se rompent, à des niveaux de contrainte constants, bien au-dessous de la valeur de la résistance statique ultime en traction.

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Copyright information

© Secrétariat de Rédaction 1974

Authors and Affiliations

  • D. J. Cook
    • 1
  • M. N. Haque
    • 2
  1. 1.School of Civil EngineeringThe University of New South WalesAustralia
  2. 2.School of Civil EngineeringThe University of New South WalesAustralia

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