Study of the suitability of unfired clay bricks with polymeric HDPE & PET wastes additives as a construction material

Under the framework of the Moroccan circular economy 2030 strategy, this study investigates the use of solid polymeric wastes as an alternative additive material in the construction sector. Polymeric waste additives improve both the bulk density and thermal conductivity of clay bricks; unfortunately, this comes at the expense of their mechanical properties. This paper presents an innovative way to improve the performance of unfired clay bricks with polymeric, HDPE and PET, additives to meet the Moroccan testing standards in the building sector, without using expensive organophilic and stabilizing treatments. X-ray Diffraction and Fluorescence analysis show that the used extracted clay is of an Illite type with non-swelling characteristics. Three different additive grain-sizes (delta <= 1 mm; 1 mm<= 3 mm and 3 mm<= 6 mm) with different percentages (0%, 1%, 3%, 7%, 15% and 20%), by weight, are investigated. The microscopic snapshots and experimental measurements reflect a low porosity level when using the smallest polymeric grain additive size (delta <= 1 mm), which results in improving the brick sample's performance. In fact, bulk density measurements show that the prepared specimens can be classified as lightweight bricks, as their density does not exceed the 1.75 g/cm(3) mark. Besides, capillary water absorption coefficient and compressive strength properties are also improved by almost 17% and 28%, respectively, when using the smallest polymeric-grain additives of size (delta <= 1 mm) if compared to the largest ones of size (3 mm<= 6 mm).