Using numerical techniques to accelerate delayed ettringnite formation test methods

Scope and Method of Study. A numerical technique to be used to estimate the final results of tests with symmetric S-curves, specifically delayed ettringite formation expansion tests. Also Lab testing of cores with suspected DEF.;Findings and Conclusions. Delayed ettringite formation (DEF) in concrete can cause significant damage to structures. Finding the severity of the DEF is beneficial. Currently to measure the potential DEF expansion, lab testing is required that could take up to 2 years to complete. This thesis presents two methods to shorten DEF expansion tests. Each method focuses on the following: fitting a curve to the data, assuming an inflection point, interpolating to the expansion of the found inflection point, and doubling the expansion found to obtain the final expansion.;After considering each method, partial data from completed DEF expansion tests were used to compare final expansion results. Both methods accurately and consistently found final expansions while saving on average over a year of testing time. Making use of these methods would increase the time it takes to get information to the field about DEF expansions. Improving decision-making time concerning maintenance.;DEF testing of cores from two projects was also performed. The Fu expansion test was used to measure the expansion of the cores over time.