Location
Leeds University
Keywords
Concrete, Durability, testing, ASR, chloride penetration, freezing and thawing, sulfate attack
Abstract
Many performance-based durability test methods adopted in various national and international standards were developed decades ago based on short-term evaluations. Most durability tests use various methods to accelerate reactions in order to obtain results in a reasonably short period of time. Then pass/fail criteria are set for these tests in standard specifications. However, the acceleration techniques used maybe overly severe, and preclude the use of concrete materials and mix designs that perform perfectly well in the field. The inclusion of long-term field tests or outdoor exposure tests can be used to verify the appropriateness of both the test methods and the test limits. This provides more confidence that the results from the test methods are meaningful and that the adopted specification limits are appropriate. This approach has been used to verify or modify ASTM and CSA test methods for sulfate resistance, mitigation of alkali-silica reaction, de-icer salt scaling resistance, and for resistance to chloride ingress for marine and deicer exposures. However, in addition to the time and costs for such programs, another limiting factor can be that the materials and mix designs used in the long-term tests may no longer be representative of those currently in use. As another issue, the precision of all test methods needs to be evaluated by inter-laboratory test programs to provide confidence in the reproducibility of 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.
Included in
Using Long-Term Outdoor Exposure Data to Benchmark Accelerated Durability Test Methods
Leeds University
Many performance-based durability test methods adopted in various national and international standards were developed decades ago based on short-term evaluations. Most durability tests use various methods to accelerate reactions in order to obtain results in a reasonably short period of time. Then pass/fail criteria are set for these tests in standard specifications. However, the acceleration techniques used maybe overly severe, and preclude the use of concrete materials and mix designs that perform perfectly well in the field. The inclusion of long-term field tests or outdoor exposure tests can be used to verify the appropriateness of both the test methods and the test limits. This provides more confidence that the results from the test methods are meaningful and that the adopted specification limits are appropriate. This approach has been used to verify or modify ASTM and CSA test methods for sulfate resistance, mitigation of alkali-silica reaction, de-icer salt scaling resistance, and for resistance to chloride ingress for marine and deicer exposures. However, in addition to the time and costs for such programs, another limiting factor can be that the materials and mix designs used in the long-term tests may no longer be representative of those currently in use. As another issue, the precision of all test methods needs to be evaluated by inter-laboratory test programs to provide confidence in the reproducibility of 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.
