Clay-aerogel mixtures for bricks fabrication: Experimental characterization and thermal performance simulation

The improvement of bricks thermal and acoustic performance is a one of the challenges of the construction industry to face the regulatory requirements. To this aim, in the present paper, aerogel granules were mixed with clay to study partition bricks capable of ensuring excellent thermal and acoustic performance for opaque walls. Five mixtures were performed with different weight percentages of granular aerogel (0 %, 2 %, 3 %, 4 %, 5 %). As the additive content increases, the density of the samples decreases, leading to a reduction in thermal conductivity (0.31 W/mK for pure clay and 0.21 W/mK with 5 % aerogel) and an improvement in sound absorption performance, with a peak value of 0.3 at 1600 Hz. However, a slight reduction in transmission loss values (TL = 33–45 dB for 0 %, TL = 26–34 dB for 5 %) is observed. The presence of the granules in the mixture involves an increase in porosity (water vapor resistance factor decreases from 55 to 23.5). Additionally, the preliminary mechanical analyses demonstrate that the presence of aerogel does not result in significant changes in terms of flexural and compressive strength. The data measured during the experimental characterization were used to investigate the influence of the studied mixtures on the thermal performance of partition bricks selected from the company's catalog through Computational Fluid Dynamics (CFD) analysis, and a critical analysis was conducted based on the geometric characteristics, perforation percentages, and hole types of each brick. For all types of partition bricks, there is a reduction in thermal conductivity as the percentage of granules increases (maximum reduction of 14.3 %), despite the transition from 2 % to 3 % does not result in significant changes in thermal performance.