Deformational and energy-absorption performance of low-strength structural concrete with joint additions of raw-crushed wind-turbine blade and coarse recycled aggregate

Abstract Raw-Crushed Wind-Turbine Blade (RCWTB) is yielded through non-selective cutting and crushing of wind-turbine blades, which has a high content of fiberglass-composite fibers. These fibers can potentially increase the energy-absorption capacity and ductility of concrete, and even partially compensate for the higher brittleness because of the addition of Coarse Recycled Aggregate (CRA). This paper therefore analyzes the behavior under monotonic compressive and bending loading of low-strength structural concrete (target compressive strength of 25 MPa) produced with CRA amounts of 50% and 100% and RCWTB contents of 0% and 10%. Both the under-bending load-deflection curves and the under-compression stress-strain curves in both the longitudinal and transverse directions showed that RCWTB increased concrete deformability. Thus, it decreased the elastic stiffness and increased the fracture and peak strains and deflections, improving the load-bearing capacity. Compressive and flexural strengths were not adversely affected by RCWTB, so that a higher deformability augmented the absorbed energy. This gain was as high as 469% when a bending load was applied to low-strength concrete with 50% CRA. The pre-failure beneficial effect of RCWTB was more noticeable for a CRA content of 100% in the under-compression longitudinal stress-strain performance, due to the higher tensile stress supported by the RCWTB fibers prior to failure. However, the most suitable CRA content in the under-bending load-deflection performance and the under-compression stress-strain behavior in the transverse direction was 50%, which limited the micro-cracking of the cementitious matrix. The interaction between both wastes was statistically key to define the deformational and energy-absorption behavior of the low-strength structural concrete made with CRA and RCWTB simultaneously.