Flexural Strengthening of RC Beams with Cement-Based Composites

In this paper, the effectiveness of fiber-reinforced cementitious matrix (FRCM) materials for the strengthening of reinforced
concrete (RC) beams is experimentally investigated. Bending tests on RC beams strengthened with different FRCM materials, made
out of (1) carbon fiber nets; and (2) poliparafenilenbenzobisoxazole (PBO) fiber nets embedded in cement-based matrix, are performed.
For case (2), different net shapes, cementitious matrices, and a number of net layers were considered. Depending on the type of fibers
and matrix, different flexural debonding failure modes are identified. The fiber strain at debonding is evaluated by comparing the experimental
results with those obtained with two different theoretical models. The results obtained in this study confirm the effectiveness of
FRCM materials for the strengthening of RC structures and encourage further experimental and theoretical work on the topic. A better
understanding of the debonding phenomenon is crucial for an optimal design of the strengthening material. The way in which the nature
of fibers and matrices and the number of layers control the performance of the strengthened members is also investigated in the present paper.