ALKALI-SILICA REACTION
PREVENTION + EVALUATION + REPAIR
At Durability Engineers, our team has deep expertise in preventing Alkali-silica Reaction (ASR) and assessing ASR-affected structures. We leverage this knowledge to offer tailored solutions for our clients, whether in the planning and design stages or during 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, triggered by the interaction between specific alkalis—typically from the cement—and reactive aggregates. This reaction leads to swelling, expansion, and cracking, which can compromise structural integrity and drastically shorten the service life of the affected structure.
PREVENTION + MITIGATION
In new construction, our team utilizes petrography, standardized and specialty testing of cements and aggregates, along with advanced materials engineering, to prevent alkali-silica reaction (ASR). We develop project tailored engineering strategies that offer effective mitigation approaches for each structure. Our services include:
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Project Specification Development
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Materials Selection and Mixture Proportioning
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Durability Consulting, including the 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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Nondestructive Testing (NDT) and Destructive Testing
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Specialty ASR Testing for Diagnosis and Prognosis
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Instrumentation and In-situ Monitoring of the Structure
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Standard and Specialty Testing
REPAIR + REMEDIATION
Following the evaluation of an ASR-affected structure, comprehensive monitoring plans, mitigation strategies, and/or repair designs can be developed. While there is no universal solution to fully stop ASR in existing structures, customized strategies will be developed in collaboration with stakeholders to extend the life and maintain the structural integrity. This process may include the development and execution of monitoring plans, regular condition assessments, and construction oversight to track performance and adjust strategies as needed.
Durability Engineers (DE) will design, initiate, and complete the monitoring process, ensuring regular communication on the performance with stakeholders. Repair designs and solutions will be implemented to address the symptoms of ASR and mitigate its effects. External confinement techniques, such as post-tensioning and fiber reinforcement, can limit expansion, while waterproofing, breathable sealers, and coatings can help prevent further moisture ingress, thereby potentially extending the life of the structure.
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Monitoring Plan Development and Execution
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Repair Design and Construction Administration
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Mitigation Design and Construction Oversight
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External Confinement (e.g., Post-tensioning and Fiber Reinforcement Design)
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Regular Condition Assessments for tracking the structure's performance
