Innovative underwater material from recycled spoil for scour hole remediation in offshore wind foundations

This study investigates the viability of Underwater Controlled Low-Strength Material (UWCLSM), developed from recycled waste spoil, for repairing scour holes in Offshore Wind Foundations (OWFs). The results confirm the feasibility of this approach, with UWCLSM demonstrating excellent anti-dispersion and self-leveling properties underwater, achieving near 400 kPa strength, and withstanding erosive water flow. Compared to traditional scour hole repair materials, UWCLSM significantly reduces costs and carbon emissions. The addition of Hydroxypropyl methylcellulose (HPMC) plays a dual role in enhancing UWCLSM. While it enables UWCLSM to resist dispersion in underwater applications, it also adversely affects the material’s flowability and strength. Incorporating 5% fly ash as a cement substitute optimizes UWCLSM's strength and flowability, while adding 0.25% Polycarboxylate Ether enhances flowability without significantly compromising anti-dispersion. Additionally, this study compares UWCLSM’s flowability and strength in water and air, analyzes the distribution of strength post-pouring, and examines the scour damage patterns. The findings highlight UWCLSM as a promising material for repairing scour holes in OWFs, contributing to sustainable construction practices and resource recycling.