Strain development in CFRP-wrapped circular concrete columns affected by alkali-aggregate reaction

• CFRP wrapping is effective in limiting AAR expansion.
• CFRP confinement at early ages shows better performance in reducing expansion.
• Efficiency of reducing AAR expansion depends upon the time of CFRP wrapping.
• Efficiency of reducing AAR expansion depends on the number of CFRP layers.

A large number of concrete bridges and dams around the world are affected by deterioration caused by the alkali aggregate reaction (AAR). Fibre reinforced polymer (FRP) is considered one of the best materials for the rehabilitation of concrete columns affected by AAR. A number of cylindrical columns of 200 mm in diameter and 500 mm height were fabricated from reactive concrete using fused silica and additional alkali in its ingredients. At different periods during AAR development, i.e., 7, 15, 30, 45, 60, 90 & 120 days after casting, external confinement by carbon fibre reinforced polymer (CFRP) was applied. The main objective of using CFRP as a confinement material was to reduce the effect of the AAR-induced expansion of the concrete. Results indicate that the efficiency of CFRP application in reducing AAR expansion depends on the time of CFRP wrapping and on the number of CFRP layers applied to the columns.