Flexural strengthening with carbon-reinforced concrete (CRC) provides a highly effective approach for preserving existing reinforced concrete (RC) structures and historic listed buildings. While the increase in load-bearing capacity has been extensively studied, less attention has been given to the behavior under service loads, which is crucial for predicting deformations and crack formation. This study presents a methodology for analyzing the behavior of a slab element, selected from a set of 36 specimens, subjected to cyclic, predominantly static load regime. The analysis concentrated on the plain steel rebars and the carbon grid in the test specimen, using distributed fiber optic sensors (DFOS). The strain profiles revealed a substantial load-bearing contribution and activation of the CRC strengthening layer under service loads.