ALKALI-SILICA REACTION
PREVENTION + EVALUATION + REPAIR
At Durability Engineers, our experts have extensive backgrounds in the prevention of Alkali-silica reaction (ASR) and evaluation of existing ASR-affected structures. We use this knowledge to provide our clients with solutions during the planning and design phases, as well as the evaluation and rehabilitation of existing structures.
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WHAT IS ALKALI-SILICA REACTION?
Alkali-silica reaction (ASR) can lead to premature failure of concrete elements and structures including pavements, bridges, tunnels, power plants, dams, and others. ASR is a chemophysical reaction within the concrete’s microstructure occurring between certain alkalis, typically from the cement, and specific aggregates. This reaction can produce significant swelling, expansion, and cracking that can lead to the loss of structural integrity and a significant reduction in service-life.
PREVENTION + MITIGATION
In new construction, our team employs petrography, standardized and specialty testing of cements and aggregates, and materials engineering to prevent alkali-silica reaction from occurring. We develop an engineering strategy that provides mitigation approaches for each structure. Our services include:
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Specification Development
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Materials Selection
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Mixture Proportioning
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Durability Consulting, Implementation of ASTM C1778 - Standard Guide for Reducing the Risk of Deleterious Alkali-Aggregate Reaction in Concrete
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Standard and Specialty Testing
EVALUATION + ASSESSMENT
In existing concrete structures, we employ state of the art techniques to evaluate existing conditions, identify the cause of deterioration and determine the potential for continued deterioration. We extract samples of the concrete and examine them in our laboratories for more in-depth characterization and testing. We augment and validate results from field investigations with petrographic and laboratory assessments. Our team provides:
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On-site Evaluations,
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Assessment of Existing Conditions,
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Non-Destructive and Destructive Testing,
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Oversight of Sample Removal,
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Specialty ASR Testing to Determine Diagnosis and Prognosis
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Instrumentation and Monitoring of the Structure In-situ
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Standard and Specialty Testing
REPAIR + REMEDIATION
After the evaluation of an ASR-affected structure, our team can develop a repair and mitigation program that addresses both deteriorated conditions and the potential for continued alkali-silica reaction. For example, expansion may be arrested by confining the structure’s elements with fiber-reinforced polymers, or through the installation post-tensioning. Also, future deterioration can be alleviated by preventing the ingress of moisture that contributes to the reaction. This can be achieved by applying waterproofing to the concrete surfaces to prevent rainwater from infiltrating the concrete. Our mitigation and repair services include:
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Construction Administration
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Repair Design
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Post-tensioning design
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Fiber-reinforced polymers
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Partial Replacement
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Mitigation Design
