Dissemination

BLADES2BUILD First Publication!

Ashal Tyurkay, Gunvor Marie Kirkelund, and Ana Teresa Lima published a review article about “State-of-the-art circular economy practices for end-of-life wind turbine blades for use in the construction industry” in Sustainable Production and Consumption of Elsevier!

BLADES2BUILD Second Publication!

Our partner R-NanoLab/National Technical University of Athens (NTUA) published a review article about “Recent Trends of Recycling and Upcycling of Polymers and Composites: A Comprehensive Review”! The review has been published in Recycling MDPI.

BLADES2BUILD Third Publication!

BLADES2BUILD Fourth Publication!

BLADES2BUILD Fifth Publication!

BLADES2BUILD Sixth Publication!

BLADES2BUILD Seventh Publication!

BLADES2BUILD Eighth Publication!

Chemical recycling of Wind Turbine Blade waste

Extensive research has been conducted on the solvolysis of pristine composite laminates with well-defined thermoset compositions (epoxy, polyester, vinyl ester). However, real-world wind turbine blades (WTBs) exhibit greater complexity, incorporating a heterogeneous mixture of thermosets, thermoplastics, and auxiliary materials such as balsa wood. The intricate nature of WTB construction presents a significant challenge in isolating individual components, necessitating a waste management approach that treats the entire blade as a mixed-stream feedstock with unknown chemical composition. Our partner Prezero provided NTUA WTB waste in order to perform the chemical recycling.

This investigation explores the development and optimization of a low-temperature (200°C) solvolysis process employing catalysts and additives, formulated for WTB waste, performed by NTUA. The utilized samples are representative of end-of-life (EOL) WTBs. The primary objective is to establish a universal process capable of accommodating the full spectrum of materials present within a WTB. Ideally, this process would facilitate the recovery of high-quality glass fibers for subsequent reuse, while simultaneously converting the resin fraction into valuable low-molecular-weight species (monomers and oligomers) suitable for utilization as feedstock in future material applications. Below there are images from Recycled glass fibers recovered by using chemical recycling process, originated from wind turbine blade waste: The rGF exhibit diameter ranging from 20 to 25 μm and fiber length up to 50 mm.

Re-use of the fibers into mortars

The aforementioned chemically recycled glass fibers are implemented into mortars to test different properties of the material, by our partner RWTH Aachen University.

Repurpose of Wind Turbine Blade waste

Our partner ACCIONA performed tests for the aggregate replacement by WTBW (wind turbine blade waste) at different dosages from 5% to 10% by concrete weight. The waste was mechanically shredded by our partners PreZero and Holcim in up to 10mm aggregate size. From the  tests carried out, the sample containing 10% of WTBW (wind turbine blade), presents good workability with the use of the last generation of superplasticizers, and a 24.7Mpa compressive strength is achieved at 28days, so the goal of C16/20 is fulfilled. The sample with the highest amount of waste shows better healing performance that the other dosages studied. Next lab-scale tests are focused on material durability characterization: water penetration, chloride intrusion, and so on. In the coming period ACCIONA in collaboration with Holcim will work together on the upscaling of BLADES2BUILD sustainable concrete to an industrial-scale prototype.

Repurpose of Wind Turbine Blade waste

Our coordinator, DTU, also processed some mortar samples with wind turbine blade waste as fiber reinforcement to find the effect of WTB waste size on the strength of cement mortars. The WTB waste was shredded from PreZero. The wind turbine blade waste was sieved into 5 different sizes: >8 mm, 2~8mm, 500μm~5mm, 63~500 μm, and <63 μm. Then 2 vol. % WTB waste was used as reinforcement in mortar samples for ASR test, compressive strength, and flexural strength. Alkali–silica reaction (ASR) is a material degradation mechanism that occurs in concrete structures. ASR is a chemical reaction occurring between the reactive siliceous aggregate particles and hydroxyl ions of the pore solution in hardened concrete. After the 3-point bending tests, a decrease in cracks when increasing the fiber size can be observed. In terms of compressive strength, we can see that the fibers connect (bridging) the cement matrix, in the broken pieces.

Circular building materials

Researchers of our partner TUe, Building Materials group, work on the development of circular building materials using mechanically treated (shredded) wastes of wind turbine blades. The two main areas of research are cement-based composites and polymer-based composites. They investigated the impact of mechanically treated wind turbine blade wastes, separated according to their sizes, on the flowability of cement mortars and flexural & compressive strength. The WTB waste was shredded by PreZero.

The waste was separated into 3 size ranges (first figure). A close look reveals that WTBW consists largely of thin glass fibers bonded together with epoxy and polyester resin (second figure). As the size of the waste used increased, the flowability of fresh mortars decreased. The results of bending and compression tests (third and fourth figures) demonstrate that with WTBW size increasing, the samples showed more ductile fracture and the fibers bridged the cracks.

Secondary polymer composites for the building sector

Our partner TUe/ Building Materials group, also works on the recycling of shredded waste of wind turbine blade (WWTB) into new secondary polymer composites for use in the building sector. To achieve this, 20mm wind turbine blade wastes were used (first figure) with polypropylene (PP) as the matrix to prepare pellets and secondary composites. The WTB waste was provided by PreZero. The pellets were produced using extrusion, and the specimens were prepared using injection moulding. Their thermal behavior was studied using thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). To enhance interfacial adhesion between the polymer matrix and the WTBW reinforcement, a coupling agent was employed, resulting in notable improvements in both mechanical and thermal properties

The mechanical testing shows the improvement of the tensile strength of the secondary composites by adding coupling agent, which enhances the interfacial strength between the matrix and fiber, consequently increasing tensile strength.

Recycling Wind Turbine Blades in Concrete: Study of fresh and hardened concrete properties

Our partner TUe/ Building Materials group, has developed mix design and study properties of fresh concrete (workability, density) and hardened concrete samples (compressive strength, tensile splitting strength, elastic modulus, flexural strength with CMOD (crack mouth opening displacement)) with mechanically shredded Wind Turbine Blade Waste (WTBW).

The WTBW with particle size below 10 mm was utilized as a partial aggregate and cement replacement and reinforcement. Compared to the control samples, the use of WTBW increased the energy absorption during failure under mechanical testing.