4SIGHT

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The 4SIGHT computer program was written to facilitate concrete performance prediction under various exposure conditions. An HTML GUI now exists, so users can now go here to use the program. The web page contains entries for the user to specify concrete properties and the boundary conditions (ionic species in contact with the concrete). 4SIGHT uses the cedar++ C++ object code library to perform a transport and reaction calculation based on user input. Currently, relevant user input includes concrete mixture proportions, cement properties, crack properties, and concrete member dimensions.

• The 4SIGHT computer program has been designed to facilitate performance assessment of underground concrete structures.
• 4SIGHT uses a continuum scale transport/reaction model to prediction the dissolution and/or precipitation of minerals and salts.
• This web application is a graphical front-end to the original command line program. A description of the assumptions, the algorithms, the validation, and the meaning of input variables are discussed in a report published by NIST. Click on NIST-IR 6747 to download the 750 kB PDF document.

The 4SIGHT computer program combines electro-diffusive transport, permeation, and chemical reaction to predict the ingress of external species dissolved in the aqueous solution that is in contact with the concrete. As species in solution reaction with the mineral phases within the microstructure (dissolution/precipitation), the porosity changes, thus changing the transport coefficient. The service life is defined as the time required for chlorides to reach a critical threshold concentration at the depth of the steel reinforcement.