Durability analysis of concrete mixes with raw-crushed wind-turbine blade and recycled concrete aggregate: A modeling approach

Residues from the wind energy sector represent a potential source of raw materials for incorporation into concrete. Specifically, Recycled Concrete Aggregate (RCA) and Raw-Crushed Wind-Turbine Blade (RCWTB) have shown promise in improving the environmental eco-efficiency of concrete, without compromising its mechanical performance. This study focuses on the durability properties of concrete mixes incorporating RCA at levels ranging from 0 % to 100 %, and between 0 % and 10 % of RCWTB. The properties evaluated included porosity, Water Absorption (WA) rate, and abrasion resistance. A modeling approach through Response Surface Method (RSM) was employed to optimize the mix design based on these durability parameters. The results indicated that the inclusion of both RCA and RCWTB overall increased porosity and WA rate, although the glass fiber-reinforced polymer fibers in RCWTB partly mitigated this effect, probably acting as barriers to water penetration. Thus, the presence of these fibers also improved abrasion resistance values when added in intermediate contents. Optimal combinations of up to around 5 % RCWTB and about 10 % RCA were identified following numerical and graphical RSM optimization aimed at minimizing all durability indicators simultaneously. Finally, global numerical optimization, considering mechanical, durability, and eco-efficiency criteria, and following normalization of all concrete properties, identified an optimal mixture containing 3.1 % RCWTB and 46.7 % RCA, in which higher waste contents were yielded, as durability performance accounted for only one-third of the optimization weight. Overall, sustainable concrete containing from low to medium contents of wind-industry-derived residual materials can be developed, yielding a balanced mechanical, durability, and environmental performance.