Enhancement of the thermal performance of perforated clay brick walls through the addition of industrial nano-crystalline aluminium sludge

• Characterization of innovative eco-thermo-efficient hollow clay bricks.
• Recycling of industrial nano-crystalline aluminium sludge.
• Eco-efficient bricks with improved thermal performance (U-value almost 10% lower).
• Combined experimental/numerical approach to assess thermal performance.
• Importance of mortar joints in the overall wall thermal transmittance value.

One of the most common approaches to contribute to the sustainability of the construction sector consists in adding industrial by-products to raw materials. However, this generally presents the major drawback of leading to a loss of the product’s properties. The study herein presented is part of a research project, developed in co-promotion with a manufacturer of perforated clay bricks, with the final goal of incorporating industrial nano-crystalline aluminium sludge in the raw material, but with the additional goal of improving the thermal properties of the original product.A combined experimental/numerical approach has been used to assess the thermal performance of walls built with the new eco-efficient perforated clay bricks. First, tests were conducted on laboratorial prototypes and relevant parameters were measured. Next, a numerical analysis was performed using three-dimensional finite element models, calibrated and validated using the experimental results. Furthermore, the results were compared with other simplified models (2D) and its reliability assessed.The obtained results show that the new eco-efficient perforated clay bricks exhibit better thermal performance than the original product, leading to almost 10% improvement of its thermal transmittance.