Water and fertilizer retention characteristics of sustainable bio-based aggregate concrete for vegetative applications

Porous ecological concrete plays a crucial role in promoting sustainable development and green infrastructure construction. The limited water and fertilizer retention capacities of conventional porous concrete are the primary factors causing plant growth degradation quickly when used for vegetal restoration. To improve the plant growth performance of porous concrete in a natural environment, heat-treated kernel peach shell aggregate (HPS-aggregate) is used as a carrier for water and fertilizer storage of sustainable bio-based porous concrete. The physical and mechanical characteristics, plant growth performance, nutrient absorption and release behaviour are investigated in this study. The results indicate that the aggregate types have an influence on the plant growth performance, i.e., bio-based aggregate concretes exhibit better plant growth than conventional aggregate concrete, thanks to their superior water retention and nutrient supply capabilities. The water absorption of bio-based aggregate concrete increases by 325–479 % at 72 h, compared to conventional aggregate concrete. The addition of the HPS-aggregate improves nutrient uptake and release capacities of porous concrete. In addition, nutrient solution soaking treatment can further promote plant growth throughout seasonal variations, and bio-based aggregate concrete not only supports grass growth (festuca arundinacea) but also promotes the healthy growth of shrubs (amorpha fruticose). It can be concluded that using partial HPS-aggregate in porous concrete (LPS concrete) in conjunction with nutrient solution soaking treatment can significantly promote plant growth. • Bio-based aggregates significantly enhance water retention capacity. • Enhanced water–fertilizer supply boosts plant growth across all seasons. • Nutrient solution soaking pretreatment further enhances plant growth.