Low alkaline vegetation concrete with silica fume and nano-fly ash composites to improve the planting properties and soil ecology

Abstract

Abstract Slope protection and erosion management are severely hampered by the rapid infrastructure development in mountainous valleys, especially during the monsoon season. While conventional approaches like vegetation, porous concrete, and inorganic procedures have been used, stronger and more ecologically friendly alternatives are still needed. A new kind of concrete called vegetation concrete (VC) allows roots to grow through the concrete frame by combining plant integration with porous concrete. This creative method might be used for environmentally friendly building and planting. The alkalinity of VC significantly impacts its planting capabilities and soil nutrient levels, making it crucial to reduce VC alkalinity. In this study, silica fume (SF) and fly ash (FA) were combined to create low-alkaline VC. The effects of SF and FA on VC’s alkalinity, porosity, compressive strength, and planting characteristics were examined. The study also investigated VC’s influence on soil fertility and its impact on soil nutrients. Test results revealed that SF and FA reduced the pH of the VC by reducing calcium hydroxide (CH) crystals. While SF had a lower basicity coefficient (M) than FA, it had a more significant effect on lowering VC alkalinity. The compressive strength decreased with FA but increased with SF, despite SF having a smaller cement component in VC–SF mixes. This suggests that blending VC with SF and FA is feasible, with the SF dosage exceeding the FA dosage for reduced alkalinity and increased strength. Lowering VC alkalinity through SF and FA increased soil nutrients, including hydrolyzable nitrogen (AH-N), extractable phosphorus (P), and potassium (K). It also improved planting properties like root development, stem height, and leaf relative water content. Using VC for soil stabilization did not reduce soil fertility but instead increased the available phosphorus and alkali-hydrolyzable nitrogen in the soil by 32.81 and 52.92%, respectively. The findings of this study open up new avenues for investigation into this technology and have important ramifications for the use of VC technology, particularly in Indian contexts.