Internal water curing with Liapor aggregates

Pietro Lura
Technical University of Denmark, Department Civil Engineering, Lyngby, Denmark and
Delft University of Technology, Faculty of Civil Engineering and Geosciences, Delft, The Netherlands

Internal water curing is a very efficient way to counteract self-desiccation and autogenous shrinkage in high performance concrete, thereby reducing the likelihood of early-age cracking. This paper deals with early-age volume changes and moisture transport in lightweight aggregate concrete realized with wet lightweight aggregates. Lightweight aggregate concrete mixtures with different degree of saturation and different particle size of the lightweight aggregates were studied and compared to normal weight concrete. Autogenous deformations, self-induced stresses in fully restrained conditions, elastic modulus and compressive strength were measured. Early-age expansion of the mixtures was greater the higher the degree of the saturation of the lightweight aggregates and the finer their particle size. The elastic properties and the early-age expansion of the lightweight aggregate concrete were calculated with simple composite models, showing good agreement with the experimental findings.

Key words: Lightweight aggregates, autogenous deformation, self-induced stresses, internal water curing