Water Transfer and Insulation Dynamic of Green Roofs with Coarse Recycled Materials

The thesis presents alternative materials for substrate and drainage in green roof layers. Comparison between substrate with recycled coarse materials (SP) and substrate without recycled coarse materials (SC) has been studied. For the drainage layer, the results of Recycled Coarse Aggregate (RCA), Incinerated Municipal Solid Waste Aggregate (IMSWA) and Lightweight Expanded Clay Aggregate (LECA) were compared with those of Natural Coarse Aggregate (NCA). Three leading indicators as dependent variables are measured for green roof systems: Rc-value, water permeability and water retention capacity. Further experimental research on the rainfall detention performance as well as hygrothermal performance of green roof models including recycled coarse materials is presented. Further modeling research on the hygrothermal performance of green roof models under the temperate climate of Liège city is then presented, according to 3 weather scenarios: beginning, middle and end of the 21st century, corresponding to variable temperatures and rainfall. The heat flux sensitivity to the thickness and physical characteristics of green roofs with artificial and recycled materials is assessed. According to the results, using coarse recycled and artificial materials can allow targeting minimum requirements for the water permeability, water retention capacity and thermal resistance. Also, the heat resistance of green roof models produced with artificial and recycled materials increased for scenario 3 in comparison to scenarios 1 and 2 during the summer and the beginning of autumn due to a drop in the rainfall pattern till the end of the 21st century. The parameters change in the sensitivity analysis showed that the scatter of the thermal conductivity, layer thickness and density affect the dispersion of heat flux for the green roof layers.