Water permeability, water retention capacity, and thermal resistance of green roof layers made with recycled and artificial aggregates

Substituting natural aggregates in the green roof substrate and drainage layers with lightweight artificial recycled coarse materials is an eco-friendly alternative for applying lower load to rooftops preserving resources. However, a lack of precise understanding thermal resistance, water passing ability, holding capacity materials, including has raised demand measuring their Rc-value, permeability, retention as three main indicators systems. This study comparatively evaluated roofs layers, materials. Different kinds granular were separately used layer, Natural Coarse Aggregate (NCA), Recycled (RCA), Incinerated Municipal Solid Waste (IMSWA), Lightweight Expanded Clay (LECA). The made (SC) without (SP) wet dry states. outcomes revealed highest resistance lowest weight obtained 20-cm 15-cm layer 5-cm LECA. permeability NCA was 1.5 times more than that LECA, whereas there no significant difference between result former, RCA, IMSWA. LECA two higher NCA. SC SP satisfied criteria given roofs. • material replaced expanded clay provided Rc-value. Without substrate's increased by times. Substrate criteria.