Lightweight Aggregates with Special Microstructure for Use in Rooftop Garden Design

Continuous urban land development is causing environmental changes. The most visible effects are a decline in biodiversity, an increase in urban temperatures, and changes in the water balance. Recently, very intense and sudden rainfall events have been observed, and existing drainage systems are not effective enough. Urban surfaces tend to be impermeable with low retention, so there is no way to respond to both the rainy periods and the drought periods that often follow. A good remedy for these factors is urban greening, which can be achieved through the design of green roofs and living walls. The substrate used for this type of construction should be light, permeable, and retentive. This study aimed to produce artificial aggregate granules with various additives that modify the structure to create open mesopores and facilitate better rainwater management. Through suitable sintering, materials with water absorption of more than 40%, retention in simulated rainfall of over 35% and a bulk density of ~0.70 g/cm3 were obtained. Detailed microstructural analyses were carried out using various microscopic techniques. Strength tests and simple vegetation tests were also carried out.