Specific Design of a Self-Compacting Concrete with Raw-Crushed Wind-Turbine Blade

Wind-turbine blades pose significant disposal challenges in the wind-energy sector due to the increasing demand for wind farms. Therefore, this study researched the revaluation of Raw-Crushed Wind-Turbine Blade (RCWTB), obtained through a non-selective blade crushing process, as a partial substitute for aggregates in Self-Compacting Concrete (SCC). The aim was to determine the most adequate water/cement (w/c) ratio and amount of superplasticizing admixtures required to achieve adequate flowability and 7-day compressive strength in SCC for increasing proportions of RCWTB, through the production of more than 40 SCC mixes. The results reported that increasing RCWTB additions decreased the slump flow of SCC by 6.58% per 1% RCWTB on average, as well as the compressive strength, although a minimum value of 25 MPa was always reached. Following a multi-criteria decision-making analysis, a w/c ratio of 0.45 and a superplasticizer content of 2.8% of the cement mass were optimum to produce SCC with up to 2% RCWTB. A w/c ratio of 0.50 and an amount of superplasticizers of 4.0% and 4.6% were optimum to produce SCC with 3% and 4% RCWTB, respectively. Concrete mixes containing 5% RCWTB did not achieve self-compacting properties under any design condition. All modifications of the SCC mix design showed statistically significant effects according to an analysis of variance at a confidence level of 95%. Overall, this study confirms that the incorporation of RCWTB into SCC through a careful mix design is feasible in terms of flowability and compressive strength, opening a new research avenue for the recycling of wind-turbine blades as an SCC component.