Thermal conductivity modelling of structural lightweight aggregate concrete

Various thermal conductivity models for multi-phase materials have been suggested in the literature. However, none have been specifically developed or adapted for structural lightweight aggregate concrete (SLWAC). In this context, the main purpose of this study was to develop a new simple model to predict the thermal conductivity of SLWAC, taking into account the volume fraction and thermal characteristics of each phase and an empirical factor that considers the uneven heat flux distribution through them. The study was based on an extensive experimental campaign carried out for different water to cement ratios and types and volume fractions of aggregate. Moreover, given that there are no standards for determining the thermal conductivity of lightweight aggregates (LWAs), a new technique was devised. The proposed model is easily implemented in practice, contributing to expeditious estimation of the thermal conductivity of the most common SLWAC regardless of the type of LWA and concrete composition.