Efficiency of lightweight aggregates for internal curing of high strength concrete to eliminate autogenous shrinkage

High Strength Concretes (HSC) with extremely low water to binder (w/b) ratios are characterized by high cracking sensitivity which is a consequence of increased autogenous shrinkage. The major reason for autogenous shrinkage—self-desiccation—cannot be eliminated by traditional curing methods. The application of the concept of internal curing by means of saturated lightweight aggregate was applied and shown to be effective in eliminating autogenous shrinkage. The present paper describes an approach to optimize the size and porosity of the light-weight aggregate to obtain effective internal curing with a minimum content of such aggregate.

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Résumé Les bétons de haute résistance qui ont un rapport eau/liant extrêmement bas, sont caractérisés par une haute sensibilité à la fissuration, qui est l'une des conséquences d'un retrait endogène plus important. La raison principale du retrait endogène—l'auto-dessiccation—ne peut être éliminée par les méthodes conventionnelles de cure. L'application du concept de la cure interne au moyen de granulats légers saturés a été pratiquée et s'est avérée effective pour éliminer le retrait endogène. Cet article décrit une approche visant à améliorer la taille et la porosité du granulat léger afin d'obtenir une cure interne effective avec un volume minimum d'un tel granulat.

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Editorial Note Prof. Arnon Bentur is a RILEM Senior Member. He is the Chairman of RILEM TC 181-EAS: ‘Early age shrinkage induced stresses and cracking in cementitious systems’. He is also the Chairman of the RILEM Technical Activities Committee (TAC). Dr. Konstantin Kovler is also a RILEM Senior Member, He participates in RILEM TCs 162-TDF ‘Test and design methods for steel fibre reinforced concrete’ and 181-EAS (above-mentioned). The Israeli National Building Research Institute is a RILEM Titular Member.