182 / 2022-04-30 19:03:03

Performance assessment of LC3 concrete structures considering life-cycle cost and environmental impacts

LC3; Seawater Sea sand; RCA; FRP; Environmental impacts; CO2 emissions; Energy consumption.

Traditional concrete, composed of cement, aggregate, fresh water, and river sand, has caused huge damage to the natural ecological environment. Developing green materials in infrastructure construction is of vital importance for sustainable development. Limestone calcined clay cement (LC3) is a suitable alternative for the reduction of CO₂ emission and resource consumption in the cement industry. Recycle concrete aggregate (RCA), seawater and sea sand are potentially advantageous from a sustainability perspective, especial in coastal regions. Fiber-reinforced polymer (FRP) bars with excellent corrosion resistance are ideal alternative materials for steel bars in a corrosive environment to minimize maintenance. In this paper, a type of green concrete structure combining LC3, seawater, sea sand, RCA, and FRP bar has been focused on, and the structural performance considering life cycle cost and environmental impacts have been assessed to verify the considerable sustainable advantages.



Compared with traditional concrete, the green concrete developed has lower cost and environmental impact (Fig.1, Fig. 2): the global warming potential (GWP) and energy consumption have reduced by 40.9% and 25.6%, respectively.  In addition, the effects of the substitution rate level of LC3, the production process of calcined clay and cement, and the transportation distance of RAC on the environmental impacts and cost have been identified quantitatively. The results show that the GWP and energy consumption for the green concrete with a 50% substitution rate of LC3 was 14.6% and 6.1% lower than that of the 35% substitution rate. Compared with the remaining two production processes, the environmental impacts of the high investment best available technology (BAT) level have been reduced by 26%~33.7% (CO₂ emissions) and 17%~40.2% (energy consumption) (Fig.3, Fig. 4). With the decrease in the distance from demolished buildings to the recycling process plant, the environmental impacts of the green concrete were reduced gradually, indicating that the utilization of RCA in a more sustainable form depends on the continuous optimization of recycling planning in urban (Fig.5, Fig. 6).