A bionic mineral precipitation method to improve the mechanical and vegetative properties of ecological concrete

Ecological concrete (EC) serves as a crucial component in slope protection, facilitating the exchange of materials and energy between the riverbank and the river itself, thereby mitigating ecological disturbances and averting biodiversity degradation. Nonetheless, the high mechanical strength of cementitious EC is often not satisfied simultaneously with its low internal alkalinity, which may be detrimental to its application in ecological slope protection. To address this challenge, this study introduces a bionic mineralization treatment approach for EC, drawing inspiration from hydroxyapatite (HAP), a biomaterial found in human teeth. This treatment involves immersing EC in solutions of diammonium hydrogen phosphate (DAP) and dipotassium hydrogen phosphate (DPP) to induce the in-situ precipitation of HAP. Experimental findings reveal that DAP and DPP treatments significantly reduce the alkalinity levels within the pores of EC, decreasing from 11.1 to 8.5. This alteration demonstrates stability, with a slight rebound to 8.7 observed after a two-month immersion in water. Consequently, tall fescue germination rates within the EC substrate exhibit a substantial enhancement of 90 %, accompanied by a corresponding 120 % increase in leaf height over a period of 35 days. Additionally, a noteworthy enhancement in the compressive strength of ecological concrete by 26.2 % is observed, attributed to the refinement of pore structure resulting from the formation of calcium phosphate and HAP. This mineralization technique not only improves the vegetative properties of ecological concrete but also showcases significant potential for application in ecological slope protection endeavors. • A bionic mineralization technique to improve vegetative properties of ecological concrete was explored. • The conversion of calcium phosphate to hydroxyapatite were facilitated in situ. • DAP and DPP treatments significantly reduce the alkalinity levels within the pores and compressive strength of EC. • Vegetative properties including tall fescue germination rates and leaf height were significantly improved by proposed method.