Performance of strengthened lightweight concrete T beams anchored in flexure with CFRP fiber anchors

This paper evaluates for the first time the flexural response of sand-lightweight Perlite concrete using full-scale reinforced concrete T beams strengthened and anchored with carbon fiber reinforced polymer (CFRP) materials. Six specimens were prepared with the same geometry, steel reinforcements, and concrete properties. The beams had a similar number of CFRP sheets but were anchored utilizing a progressively increasing number of CFRP fiber anchors. This allows effective assessment of flexural improvement in full-scale sand-lightweight Perlite concrete beams when applying different numbers of fiber anchors. The experimental results were also compared with the numerical predictions, and the comparison was discussed. The test results showed some improvement in the flexural response due to the use of CFRP fiber anchors. Interestingly, the anchored beams resulted in a similar strength improvement regardless of the number of CFRP fiber anchors used in the shear span. This appears to be the outcome of a localized, unique failure mode of excessively wide cracks around the anchors due to the lack of aggregate interlock. Finally, the performance of the fiber-anchored beams herein is compared with the identical lightweight concrete beams externally anchored with U-wrap anchors.