The Effect of using Recycled Materials in Earth-Based Blocks

Polystyrene and plastic use is ubiquitous worldwide and has a detrimental impact on the environment due to their inability to decompose. Incorporating waste into earth-based building materials provides an innovative approach to utilize expanded polystyrene (EPS) and polyethylene terephthalate (PET) waste, along with other recyclable materials including paper, plastic and cardboard. The research presented in this paper discusses the material properties of earth combined with various recyclables, including paper, cardboard, with varying percentages of EPS and plastic. The effect on density, moisture content, load-deformation behaviour, and compressive strength of earth test cylinders was evaluated for non-heat treated and heat-treated specimens. A series of tests were conducted on cylinders with various mix designs. The results indicate that an increase in the EPS content results in a decrease in the density, stiffness, and compressive strength, whereas the axial deformation, and Poisson's ratio increased. Subjecting the cylinders to heat prior to testing resulted in an increased compressive strength, but decreased the average density, moisture content, axial deformation and Poisson's ratio for the mixtures. Unheated specimens with plastic exhibited higher compression values when compared to heated cylinders. Compressive strengths ranged from 1.12 to 2.25 MPa for EPS specimens while the PET specimens had a range of 1.23 to 2.23 MPa.