Effect of SCMs on heat transfer properties of LWAC

The article presents the results of an extensive experimental study focused on the effect of supplementary cementitious materials (SCMs) on concrete thermal properties. In case of normal weight concrete (NWC) and three types of lightweight aggregate concretes (LWAC), made with 6 different types of cements, the heat transfer properties of the concrete were tested and compared with density-based recommendations. The measured heat conductivities showed a significant effect of SCM materials incorporated in cement mixes, especially in case of NWC. The results of volume heat capacities were less affected by the use of different cement types in LWAC, contrary to NWC. In one set of mixes, the natural quartz sand was replaced with dacite sand to evaluate the effect of SCM materials when the LWAC is made with low-heat conductivity sand. Further, the effect of cement replacement with fly ash and bottom ash, from waste disposal (FBW), was investigated, on LWACs heat transfer properties. First, the FBWs physical properties were optimized by mechanical activation in order to achieve LWAC with low-heat conductivity and fair compressive strength. The experimental investigation demonstrated the way to obtain a contemporary green LWAC by reducing more than 80% of the cement clinker amount with SCMs.