Flexural strengthening of reinforced concrete beams with different levels of damage using ambient-cured ultra-high performance concrete

This paper proposes an ambient-cured ultra-high performance concrete (ACUHPC) by optimising its mixing procedure based on general materials. Seven reinforced concrete (RC) beams were designed and subjected to different levels of damage and strengthened using the proposed ACUHPC. Flexural experiments were performed, and corresponding finite element (FE) models were developed to investigate the flexural performance of the strengthened beams. The influence of the level of damage and thickness of the ACUHPC strengthening layer on the response of the beams was evaluated. The scope of application of the proposed ACUHPC strengthening method, suggestions for its implementation, and methods for estimating the flexural capacity and mid-span deflection of the strengthened beams are presented herein. The results indicated that using the ACUHPC can significantly increase the flexural capacity and effectively decrease the deflections and maximum crack width of the strengthened beams. Furthermore, the flexural capacity of the most severely damaged beam was enhanced by 36.3% after strengthening.