Prediction model of long-term chloride diffusion into plain concrete considering the effect of the heterogeneity of materials exposed to marine tidal zone

Prediction model of chloride diffusion in concrete considering the coupling effects of coarse aggregate and steel reinforcement exposed to marine tidal environment

“…The chloride concentrations in concrete specimens with various coarse aggregate volume fractions, as expected, increase with the exposed time increasing, whereas decrease with the diffusion depth increasing. These variation trends for chloride profiles are consistence with the results reported in literatures [5,11,12,16,17].…”

“…(11) only take account of the influences of coarse aggregate volume fraction and indirect blocking effect of steel reinforcement, whereas the direct blocking effect of steel bar is not considered in Eq. (11). Accordingly, the chloride concentrations predicted by Eq.…”

“…0) and the chloride diffusion coefficient D should be both considered as time-dependent parameters resulting in C s = C s (t) and D = D(t) [25], where C s means the surface chloride concentration (%). Formulas of C s (t) can be expressed as linear, square-root, power, exponent, and logarithmic functions [11]. Also, the time-dependency of chloride diffusion coefficient D(t) is more appropriately modeled based on a power function proposed by Thomas and Bamforth [26] as follows:…”

“…The T-D model can elaborate the variation characteristics for chloride diffusion coefficient of concrete with exposure time and diffusion depth varying. Wang et al [11] investigated the effects of the heterogeneity of concrete materials (consistent with the influence of coarse aggregate) on long-term chloride diffusion in concrete using the meso-scopic FEM, and an empirical model for predicting long-term chloride profiles in concrete considering the various volume fractions of coarse aggregate was elaborated. Wang et al [12] explored the effects of volume fraction and maximum size of natural coarse aggregate on chloride profiles and diffusion characteristics for concrete under dryingwetting cycles.…”

“…Despite of all these laudable achievements during the previous investigations, however, the existing researches related to the effects of the coarse aggregate and steel reinforcement on chloride diffusion either considered the coarse aggregate volume fraction (or coarse aggregate content) only [5][6][7][8][9][10][11][12]17], or taken into account the blocking effect of steel bar separately [13][14][15][16]. The coupling effects of coarse aggregate and steel reinforcement on chloride diffusion in concrete required to be deeply researched and explored.…”