Journal of Life Cycle Assessment, Japan Vol. 13(2017) No. 2

Objective. Since 2011 great East Japan Earthquake, operating ratio of coal-fired power generation has been increasing and the amount of emission of fly-ash which is by-product of operation also has been increasing. Therefore, recycling of fly-ash needs to be accelerated to consider the environmental responsibility. Fly-ash is used as a supplementary cementitious material in the production of cement concrete. A well-proportioned fly ash concrete mixture will have improved workability of fresh concrete and long term strength and mass transfer resistance of hardened concrete when compared with a normal cement concrete. Currently, some concrete plant has been shipping fly-ash concrete positively in Shikoku Island in Japan and giving satisfactory results of shipping. In future, informing the effect of concrete quality improving effect and Life Cycle Cost (LCC) reduction effect due to quality improvement of usage of fly-ash. This research aims on developing life cycle model of infrastructure used concrete used fly-ash as binder and calculating LCC for investigating the effect of LCC reduction of fly-ash used concrete.
Results and Conclusions. In the study of chloride damaged road bridge and caisson constructed by steel reinforced concrete, LCC of fly-ash used concrete calculated higher than normal concrete, though LCC per year of fly-ash used concrete is much lower than normal concrete due the life time of fly-ash concrete estimates much longer than normal concrete. In the study of carbonation effected road bridge constructed by steel reinforced concrete, life time of both structures are the same, therefore both LCC and LCC per year is the most lowest in case of normal concrete due the materials cost of fly-ash used concrete is more expansive than normal concrete. Therefore, fly-ash using for concrete to reduce LCC of infrastructure is effective for chloride damaged structures or combined carbonation and chloride damaged structure.