Often used in the construction of sustainable buildings, production of cement can result in significant carbon dioxide emissions. Clay, which is also frequently used, suffers from cracking due to shrinkage. Is there an alternative solution that reduces the amount of cement required, but improves the resistance of building materials to cracking? Researchers Salifu Tahiru Azeko, Ph.D., A.M.ASCE; Emmanuel Kwesi Arthur, Ph.D.; Doan Pham Minh; and Nathalie Lyczko, Ph.D. explore how to integrate different types of waste materials into the development of robust and sustainable building materials.

Their paper published in the Journal of Materials in Civil Engineering, “Mechanical and Thermal Properties of Sustainable Composite Building Materials Produced by the Reprocessing of Low-Density Polyethylene, Biochar, Calcium Phosphate, and Phosphogypsum Wastes”, looks at using various forms of waste to create brick composites. They used recycled plastics, calcium phosphate, and phosphogypsum into laterite (clay with high iron oxide content) composite materials and studied the strength and fracture toughness of the resulting composites. Read more about their findings in the abstract below, or by reading the full paper in the ASCE Library, https://doi.org/10.1061/(ASCE)MT.1943-5533.0004021.          


This paper presents the results of the experimental and analytical studies of the mechanical and thermal properties of laterite composites mixed with reprocessed low-density polyethylene waste (LDPE), calcium phosphate (CaP) and phosphogypsum wastes, and biochar to form brick composites. Bricks with mixtures of 20% by volume LDPE, 15% by volume CaP, and 15% by volume gypsum were shown to have excellent compressive strength, flexural strength, and fracture toughness. The composites with 1% by volume LDPE and 15% by volume biochar had the best blend of mechanical properties, such as flexural strength and fracture toughness, after sintering for ∼24 h. There was a linear association between the strength and the weight loss of the bricks. Scanning electron microscopy and optical microscopy images revealed evidence of crack bridging by LDPE particles. The laterite–LDPE composite mixed with 5%, 10%, and 15% by volume biochar had sintering temperatures of ∼850°C, ∼720°C, and ∼710°C, respectively, after undergoing softening, cold crystallization, and cooling.

Read the full paper in the ASCE Library: https://doi.org/10.1061/(ASCE)MT.1943-5533.0004021