CHLORIDE INGRESS IN CONCRETE: SIMULATIONS OF EXAMPLES FROM PRACTICE

摘要

Durability of concrete structures is not only a concern for existing older structures but nowadays it receives a lot of attention during the design phase. In addition to the usual structural calculations for concrete, increasingly reliable calculations can be performed for this material regarding the interaction of heat flow, mass transfer and mechanics. Typical topics are concrete cracking by heat of hydration, drying shrinkage cracking or chloride ingress in concrete as influenced by moisture movements. It is well-known that chloride ingress is one of the main causes of reinforcement corrosion. In the presented computational model for chloride ingress in concrete, ion transport is explicitly linked to heat and moisture transport. Free chloride ions diffuse through the (partially) water-filled pores in concrete, while they are simultaneously convected by moving moisture. In the paper the background of the model is described in detail. Furthermore the implementation of the model into a user-friendly software environment is explained. With the model a practical example is simulated. Measured chloride profiles are compared with the simulated results and on the basis of the simulations a prediction of the remaining service life is made.