Study on Alkali Reduction Treatments and Plant Growth Properties of Planting Concrete

Abstract

The use of planting concrete (PC) is one of the most prevalent slope protection methods. However, PC offers poor plant growth properties and poor ecological performance due to its high alkalinity. Therefore, in this study we used an orthogonal experimental design to optimize the mix design, and we used three alkali reduction treatments to reduce alkalinity and improve plant growth properties. The compressive strength, interconnected porosity, and pH values were analyzed to obtain the optimal level. Subsequently, the plant growth property test was conducted both indoors and outdoors. Stem length was used to evaluate different plants, which were grown in both natural soil (NS) and construction waste (CW). The experiment results show that the paste–aggregate ratio (PR) has the greatest impact on the above properties and that the optimum levels for PR, water–binder ratio (W/B), and fly ash addition level (FA) are 1/5, 0.29, and 10%, respectively. Additionally, the compound alkali reduction treatments, which combined the use of 0.4% ferrous sulfate in the planting substance and 3% potassium dihydrogen phosphate in the soaking solution, were effective. Furthermore, tall fescue may have potential applications in combination with CW. In conclusion, PC that has undergone alkali reduction treatments shows potential for application in slope protection, and thus may help to improve sustainability.

Research and Application Progress of Vegetation Porous Concrete

“…Therefore, the flowability of the paste in vegetation porous concrete is crucial for ensuring the uniformity, workability, and fillability of the material during construction. Several factors influence the flowability of the paste in vegetation porous concrete, including the water-cement ratio [32,64], additives [65], cement material quality [66], equipment, temperature, and environmental conditions [67]. The combined effect of these factors determines the flow performance of the paste.…”

“…Ultimately, porosity is formed by the irregular arrangement of aggregates and serves the purpose of permeability and vegetative performance. With the mechanical strength meeting the requirements of the engineering design, a larger aggregate particle size results in a higher porosity [64], providing more space for plants, soil, and water. Effective porosity, on the other hand, relates to fluidity, and naturally, a larger effective porosity is preferable.…”