This work presents an experimental investigation on the impact behavior of large-scale reinforced concrete (RC) beams incorporating functionally graded high-performance cementitious composites. Four configurations were tested: (i) conventional RC, (ii) steel fiber-reinforced concrete (SFRC), (iii) SFRC with a bottom Ultra-High-Performance Concrete (UHPC) layer, and (iv) SFRC with a bottom UHPC layer reinforced with carbon textile. Hooked-end steel fibers enhanced crack bridging, while UHPC mixes were optimized with copper-coated fibers and mineral additions. The textile reinforcement consisted of a bidirectional epoxy-coated carbon mesh. Drop-weight impact tests were conducted using a custom-designed testing apparatus capable of delivering impact energies up to 2.27 kJ, simulating low-velocity impact conditions. The experimental setup was instrumented with piezoelectric sensors at the actuator and supports, and force data were acquired at a frequency of 20 kHz. High-speed cameras and Digital Image Correlation (DIC) were employed with aquisiton frequency of 10 kHz to monitor crack initiation, propagation, displacement fields, and strain evolution during impact. The inclusion of UHPC layers significantly improved impact resistance, energy absorption, and crack control. The hybrid SFRC + Textile-UHPC system achieved a 44.6% increase in peak load at 1.1 kJ and reduced crack openings by up to 47% at peak load and 95% at the residual stage. Under higher energy (1.7 kJ), reductions reached 87%. Steel strain at peak load decreased from 0.35% (RC) to 0.18–0.19%, while post-impact flexural moments rose by 135%, and energy dissipation by 386%. These results confirm the superior toughness and resilience of graded hybrid composite beams under impact loading. • Paper highlights • •UHPC and TRC layers significantly improve impact resistance and energy absorption. • Hybrid SFRC + TRC-UHPC beams reduce crack openings by up to 95% under impact. • •Residual resistance indices remain above 0.95, ensuring structural integrity. • •Peak load increased by 44.6% and energy dissipation up to 386% compared to RC. • Steel and textile reinforcement synergistically enhance post-impact performance.
NUNES et al. (Sun,) studied this question.