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 from 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 noncompacted sample with matric suction varying from 0 to 450 kPa. The experimental results demonstrated the complexity of municipal solid waste (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.