Investigating the Compressive and Corrosion Resistance Properties of Ultra-High-Performance Fiber-Reinforced Concrete Enhanced with Layered Double Hydroxide Nanoparticles

Abstract

Despite the growing interest in biodegradable layered double hydroxide (LDH) nanoparticles for cementitious materials, their influence on permeability-related transport behavior and chloride resistance of ultra-high-performance fiber-reinforced concrete (UHPFRC) has not yet been systematically investigated. In particular, the combined role of LDH nanoparticles and steel microfibers in governing moisture transport, chloride ingress, and mechanical performance of UHPFRC remains insufficiently understood. To address this research gap, the present study experimentally investigates the synergistic effects of LDH nanoparticles and steel microfibers on the compressive properties, permeability, and chloride resistance of UHPFRC. LDH nanoparticles were incorporated at dosages ranging from 0 to 2.5 wt% (0, 0.5, 1.0, 1.5, 2.0, and 2.5 wt%), while a constant steel microfiber content of 0.2 wt% was maintained. The performance of the modified concretes was evaluated through compressive strength tests, capillary water absorption and sorptivity measurements in accordance with ASTM C1585, mercury intrusion porosimetry (MIP) test and the rapid chloride migration test (RCMT). The results demonstrate that LDH nanoparticles effectively refine the cementitious matrix through pore refinement, hydration nucleation, and increased diffusion tortuosity, whereas steel microfibers primarily mitigate crack initiation and propagation, thereby limiting preferential transport pathways. A clear synergistic enhancement in mechanical and durability performance was observed, with a 22 % increase in compressive strength compared to the control mixture. Moreover, the incorporation of 2.0 wt% LDH resulted in approximately 37 % reduction in chloride migration and a pronounced decrease in capillary water absorption. At higher LDH contents, a reduction in efficiency was observed, indicating the existence of an optimal LDH dosage.