Abstract:
In this study, compressive strength, chloride penetration profile, and corrosion of embedded steel bars in Portland cement type V concrete containing fly ash from fluidized-bed (FC) and pulverized combustions (PC) under marine site were investigated. Fly ash obtained from fluidized-bed combustion was ground to small [article which retained on a sieve No.325 about 2-5% by weight. Fly ash from pulverized combustion was received directly from the power plants. The fly ashes were used to replace Portland cement type v at the percentages of 0, 15, 25, 35 and 50 by weight of binder. A water to binder (W/B) ratio of concrete was kept constant at 0.65. The 200x200x200 mm3 concrete cube specimens were cast and steel bar of 12-mm in diameter and 50-mm in length were embedded at coverings of 10, 20, 50 and 75 mm in concrete specimens. The cylindrical specimen with 100-mm in diameter and 200-mm in height were also cast for the strength test at 28 days of curing and 5-year exposure in marine site. Concrete specimens were cured in fresh water for 28 days and then were placed at the tidal zone of sea water at Chonburi Province. The specimens were tested for compressive strength, total chloride peneration and corrosion of embedded steel bars afer being exposed to the tidal zone of sea water for 5 yeard. The results showed that concrete containing fly ash from pulverized combustions produces a better chloride resistance than that ground fly ash from fluidized-bed combustions. All fly ash concrete had better chloride resistance and steel corrosion than that of Portland cement type V concrete. An increase of fly ash replacement in concrete (not more than 35%) could resuce the chloride penetration and steel corrosion in concrete. In addition, compressive strength development of concretes containing fly ash from pulverized combustion was higher than those of concrete containing fly ash from fluidized-bed combustion.