Title: Benchmarking Accelerated Performance Test Methods with Long-Term Testing
Author(s): R. Doug Hooton
Publication: Symposium Paper
Appears on pages(s): 4.1-4.10
Keywords: durability; field performance, test methods; alkali-silica reactivity; sulfate resistance; freezing and thawing
Many performance-based test methods adopted in various national and international standards were adopted decades ago based on short-term evaluations. Many of the durability tests use various methods of acceleration to obtain results in a reasonably short period of time, and then pass/fail criteria are set for these tests and included in standard specifications. If long-term tests conducted in the field, or at least in outdoor exposure, can verify the appropriateness of both the test methods and the test limits, then it provides confidence that the test methods are meaningful and that the specification limits are appropriate. This has been done in the case of ASTM and CSA test methods for sulfate resistance, mitigation of alkali-silica reaction, for de-icer salt scaling resistance and for resistance to chloride ingress for marine and deicer exposures. The potential downside can be that the materials and mix designs used in the long-term tests may no longer be representative of those currently in use. In addition, the precision of all test methods needs to be evaluated in inter-laboratory test programs to provide confidence in the test results obtained. This contribution describes results from several long-term test programs and inter-laboratory studies focused on verifying specific standard test methods for durability.