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原文传递 PREDICTION OF DETERIORATION: START APPLICATION OF DEICING AGENT TAKEN INTO ACCOUNT.

题名：	PREDICTION OF DETERIORATION: START APPLICATION OF DEICING AGENT TAKEN INTO ACCOUNT.
作者：	Gaal-GCM; van-der-Veen-C; Walraven-JC; Djorai-MH
关键词：	Bridges-; Chlorides-; Comparison-; Corrosion-; Deicing-chemicals; Deterioration-; Equations-; Field-measurements; Mathematical-prediction; Time-dependence
摘要：	Predicting future deterioration is not as easy as extrapolating observed deterioration from the past. During the last century many aspects of bridge construction changed in ways that will influence tomorrow's condition. Three of the most influential changes are application of deicing agents, cover thickness, and the diffusion coefficient. These changes influence the rate of deterioration. The structure's age when the deicing agent was first applied has a significant influence on the chloride ingress, as a result of the decline of the coefficient of diffusion in time. An equation with a time-dependent coefficient of diffusion that includes the duration of exposure to the deicing agent and the age when exposure started was developed. The well-known phenomena that cause deterioration of concrete are alkali-silicate reaction, sulfate attack, frost-thaw, acid attack, carbonation, and chloride ingress. Taking all these phenomena into consideration would lead to a complex deterioration model. For the time being, it is more useful to take the decisive phenomenon into consideration--chloride-initiated corrosion. The probability of corrosion from chloride ingress is determined with Fick's second law of diffusion. Only by using a first-order reliability method can the results be compared with observed deterioration. The observed deterioration of more than 50 bridges during a period of 10 years was compared with the predicted deterioration from the newly proposed model that includes the point in time that application of deicing agents began.
总页数：	Conference Title: 9th International Bridge Management Conference. Location: Orlando, Florida. Sponsored by: Transportation Research Board
报告类型：	科技报告