AAR Risk Assessment and Diagnosis

The cause - silica gel growths on reactive aggregate particles

The effect - expansion, cracking, loss of integrity

Sandberg have been continuously involved with the diagnosis of AAR since before the earliest UK mainland example was publicised more than twenty years ago. This experience embraces alkali-silica, alkali-silicate and alkali-carbonate reactivity and extends to over thirty countries. It covers both pre-construction AAR risk assessment of concrete constituents, its diagnosis and evaluation in existing structures and the provision of expert services where litigation ensues.

Pre-Construction Evaluation of Constituents

• Desk Studies of potential aggregate resources and environmental factors.
• Source assessments and aggregate sampling by experienced geologists.
• Expert petrographical examinations of aggregates.
• Indicative chemical testing of aggregates and aggregate combinations.
• Alkali content analysis of cements, additives, water and aggregates.
• Full assessment of concrete mix proposals for AAR potential.
• Recommendations for minimising AAR risk and specification advice.

Diagnosis and Evaluation of AAR in Concrete and Concrete Structures

• Expert inspection, in situ testing and sampling of structures.
• Visual and microscopical examination of concretes.
• Chemical analysis of concrete, alkalies, chlorides, cement content.
• Mineralogical and chemical analyses of reaction products.
• Core expansion testing of concrete.
• Diagnostic and remedial appraisals of potentially affected structures.