Chloride diffusion coefficient and service life prediction of concrete subjected to repeated loadings

Abstract

The chloride diffusion coefficient and the service life of concrete with different water to cement (W/C) ratios and under repeated loadings were examined. The W/C ratios were 0·30, 0·35, 0·40 and 0·45 by mass of cement. Loading, repeated five times, was applied to concrete specimens using a WHY series fully automatic testing machine; the maximum loading was 40% and 80% of the axial cylinder compressive strength ( [Formula: see text]). The diffusion coefficients were calculated from the steady state in a chloride migration test by using the Nernst–Planck equation. The service life was predicted using a Life-365 model. The results show that an increase in W/C ratio largely increases the chloride diffusion coefficient of concrete at 28 d. Five times 40% [Formula: see text] and 80% [Formula: see text] Loading increases the chloride diffusion coefficient and decreases the service life for all mixes. The service life of 10 mm concrete cover with a 0·40 W/C ratio is 4·0 years, and decreases by 10·0% and 35·0% when the repeated loadings are 40% [Formula: see text] and 80% [Formula: see text], respectively.