Compression Behavior of Municipal Solid Waste in Temperature-Controlled Isotropic Condition

Abstract

Abstract The mechanical response of municipal solid waste (MSW) under different types of loading and testing conditions has been explored by many researchers. However, the effect of temperature on MSW compressibility has yet to be investigated. Temperature enhancement is well-known in landfill engineering, mainly when the bioreactor philosophy is employed. The generated heat gradients affect the solid particles and fluid phases. As a result, the mechanical response of MSW will be different compared with the most recent research results. Only a few investigations have been conducted on the impact of temperature on MSW’s mechanical response. This research shows how temperature enhancement impacts the compression behavior of MSW specimens with different compositions. A large-scale temperature-controlled triaxial device capable of imposing temperatures up to 85°C has been used. It is shown that, with increasing temperature, the compressive strains for MSW increase. However, the waste composition, mainly the MSW plastic content, also affects these strains. The temperature enhancements increase the mechanical creep and immediate compression indexes but decrease the samples’ elastic rebound and swelling index. Furthermore, the paper analyzes how pore water pressure affects the effective stress in such varying temperature conditions considering the waste particles’ compressibility. The achieved values show that the pore water pressure effect on effective stress is reduced up to 75 % because of the particles’ compressibility. The permeability of samples was examined based on the isotropic compression results. The results confirmed that MSW’s permeability depends on the plastic content, applied confining stress, and temperature. Increasing the temperature level showed a reduction in the permeability of samples. However, this difference was not paramount.