Environmental Impacts of Glass- and Carbon-Fiber-Reinforced Polymer Bar-Reinforced Seawater and Sea Sand Concrete Beams Used in Marine Environments: An LCA Case Study

Application of glass- or carbon-fiber-reinforced polymer (GFRP/CFRP) bars makes the direct use of seawater and sea sand concrete (SWSSC) in construction feasible, which is of high interest in order to conserve the limited resources of fresh water and river sand. The present paper performed the life cycle assessment (LCA) of constructing three kinds of beams (GFRP/CFRP bar-reinforced SWSSC beams, and steel bar-reinforced common concrete (SRC) beam) in marine environments to show the environmental benefits of using FRP bar-reinforced SWSSC beams in marine environments. According to ISO 14040 and ISO 14044, stages including production, transportation, construction, use and end-of-life are within the LCA’s boundary. The ReCiPe method and eight main environmental impact categories were used to characterize the environmental impacts of those beams. LCA results indicate that one cubic meter SWSSC possesses much lower environmental impacts in terms of all eight categories compared with common concrete with the same volume when used in marine environments, with reduction rates from 26.3% to 48.6%. When the two transportation distances were set as 50 and 20 km and without considering the difference in service life, compared to SRC beam, GFRP-SWSSC beam performs better in six categories and CFRP-SWSSC beam performs better in four categories. When considering increased transportation distance and the higher durability performance, the advantageous categories for GFRP-SWSSC and CFRP-SWSSC beams increase to seven and six, respectively. The environmental impacts of all the three beams are mainly affected by the production stages.