Testing system for determining the mechanical behaviour of early age concrete under restrained and free uniaxial shrinkage

  • K. Kovler
Article

Abstract

A modified uniaxial restrained shrinkage test was developed, characterized by complete automation and high accuracy of measurements. The system developed was such that tensile stresses remained constant throughout the cross-section, excluding any premature failure of specimen. This testing arrangement enables separation of creep strain from shrinkage by means of simultaneous testing of twin specimens, one under restrained shrinkage, and the other under free shrinkage. A variety of mechanical characteristics of the concrete (individual components of strain, shrinkage stresses, moduli of elasticity, creep coefficient and tensile strength) may be determined in one test. Results using this testing arrangement are presented for concrete cured in sealed conditions for 1 day and then exposed to drying at 30° C/40% RH.

Keywords

Shrinkage Creep Strain High Strength Concrete Shrinkage Strain Shrinkage Stress 

Resume

On a mis au point un essai de retrait empêché uniaxial modifié caractérisé par une totale automatisation et une grande précision de mesures. Le système mis au point était tel que les contraintes de traction restent constantes tout le long de la section transversale, excluant toute rupture prématurée de l'éprouvette. Ce genre d'essai permet de distinguer la déformation de fluage du retrait au moyen d'essais simultanés de deux éprouvettes jumelles, l'une sous retrait empêché, l'autre sous retrait libre. Un certain nombre de caractéristiques mécaniques du béton (composants individuels de déformation, contraintes de retrait, modules d'élasticité, coefficient de fluage et résistance en traction) peuvent être déterminées en un seul essai. Les résultats obtenus avec cette technique portent sur un béton conservé dans des conditions d'étanchéité pendant un jour et exposé ensuite au séchage à 30° C/40%RH.

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Copyright information

© RILEM 1994

Authors and Affiliations

  • K. Kovler
    • 1
  1. 1.National Building Research InstituteTechnion-Israel Institute of TechnologyTechnion City, HaifaIsrael

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