Objective In response to the demands of ecological slope protection engineering, this study takes the abundant volcanic rock resources in the Tengchong area of Yunnan Province as a starting point and develops an ecological concrete material based on volcanic rock aggregate.

Methods The volcanic rocks were categorized into three groups according to particle size (16–20, 20–30, and 30–50 mm), mixed with slag Portland cement and supplemented with fly ash to prepare ecological concrete. Its compressive strength, porosity, permeability coefficient, and planting performance were then tested.

Results The results showed that: 1) at a 28-day curing age, the compressive strength was 5.2–17.2 MPa, porosity was 24.2%–31.1%, and permeability coefficient was 2.22–2.51 cm/s. 2) The strength decreased with the increase of coarse aggregate particle sizes, while the permeability coefficient increased with the increase of porosity and particle size. 3) Planting tests revealed that concrete with higher porosity exhibited better planting performance. When applied to slope protection for reservoirs and ponds, the volcanic rock ecological concrete demonstrated dual benefits of soil and water conservation and water quality purification. It was shown to reduce the comprehensive pollution index by 30%–40% through the adsorption of pollutants such as nitrogen and phosphorus.

Conclusions In summary, the volcanic rock ecological concrete combines mechanical performance and ecological functions. Its application in slope protection for reservoirs and ponds can effectively achieve soil and water conservation as well as water quality purification, providing a new material solution for sustainable slope protection and water environment restoration.