Moisture Retention Properties of Municipal Solid Waste in Relation to Compression

Abstract : Original laboratory setups are used to study the moisture retention properties of municipal solid waste taking into account the porous medium's structural evolution due to compression. A controlled suction oedometer allowed the moisture retention curves (MRCs) of compacted samples to be determined for both wetting and drainage with a matric suction range of 0 to 10 kPa. Another setup utilizing an extraction plate was used to determine a drainage MRC for a non‐compacted sample with matric suction varying from 0 to 450 kPa. The experimental results demonstrated the complexity of MSW porous medium compared to soil. The MRC of lightly and uncompacted samples did not exhibit a measurable air‐entry suction. Moreover, significant hysteresis between the wetting and drainage MRCs was observed. The experimental MRCs were interpreted with two different models, and a pore size distribution evolution with compression was proposed. Finally, the concept of field capacity in relation to the moisture retention properties is discussed.