Internal curing of high-performance concrete via waste-based porous materials

Abstract

This work presents the use of different waste based porous materials as internal curing water reservoirs in high performance concrete, which is strongly aligned with the objective of promoting circularity in the construction industry. Internal curing was studied in combination with other shrinkage reduction strategies such as the use of coal fly ash as a low reactive supplementary cementitious material, and the use of a magnesium based expansive agent. The following waste based porous materials were used: ceramic recycled aggregates, mixed recycled aggregates, coal bottom ash and wood bottom ash. A conventional lightweight expanded clay aggregate was also used. The following properties were studied on the proposed mixtures: workability, hydration, setting, air content, density, porosity, strength, volume stability and durability. Internal curing via waste based porous materials can effectively mitigate autogenous shrinkage without significantly jeopardizing other properties. However, the alternative materials should be carefully characterized and the mix proportions should be studied in depth. Furthermore, it was concluded that external curing is needed even if internal curing is used, and synergistic effects were detected between the proposed shrinkage reduction strategies. Therefore, this work presents a feasible solution for a more durable and sustainable construction