Scientists use textile ash to create extremely strong cement
Lithuanian researchers are developing new ways to turn textile waste into energy and high-performance cement materials, offering sustainable solutions for two resource-intensive sectors – textiles and construction.
image:
Dr Raimonda Kubiliūtė, a researcher at Department of Silicate Technology, Faculty of Chemical Technology, Kaunas University of Technology
view moreCredit: KTU
Researchers at Kaunas University of Technology (KTU) are developing new ways to turn textile waste into energy and high-performance cement materials, offering sustainable solutions for two resource-intensive sectors – textiles and construction.
Waste is no longer just a problem; it can become a valuable resource. Scientists at Kaunas University of Technology (KTU) in Lithuania are exploring how textile waste can be converted into energy or incorporated into the production of cement and concrete. Such solutions reduce environmental pollution, support the circular economy and open new opportunities for industry.
Every year, several billion tonnes of waste are generated in the European Union. The EU is currently updating its waste management legislation to transition to a more sustainable circular economy model. Unlike the traditional linear system – where resources are extracted, used, and discarded – the circular economy focuses on reducing waste through smart product design, reuse, repair, recycling, and more sustainable consumption. Particular attention is directed toward textiles and construction, two sectors with high environmental footprints.
The challenge of textile waste
Managing textile waste remains a global challenge. Most textile products are still incinerated or landfilled, and only a small share is recycled or reused. In Europe, only a fraction of post-consumer textiles is collected separately, and just a few per cent of used clothing is transformed into new products – fibre-to-fibre recycling technologies are still emerging.
Currently, most recycled textile materials are repurposed into low-value products such as cleaning cloths, insulation or padding. Recycling synthetic clothing is particularly difficult due to the additives used in production, which complicate sorting and processing. Microplastics are also released during washing or treatment. Because most garments consist of fibre blends, incineration and landfilling remain the most common disposal methods – yet direct incineration increases CO₂ emissions and environmental pollution.
Using textile waste in the cement and concrete industry
One promising direction for higher-value reuse is the incorporation of textile-derived materials into other resource-intensive sectors, such as cement and concrete production.
“The cement industry, especially clinker firing processes in rotary kilns, contributes significantly to environmental pollution. This is why researchers are actively seeking ways to reduce the amount of conventional cement in cement-based mixtures by replacing it with alternative binders or fillers,” says Dr Raimonda Kubiliūtė of the KTU Faculty of Chemical Technology.
Across the cement and construction sectors, scientists are developing innovative strategies to reduce the share of ordinary Portland cement without compromising – and sometimes even improving – material performance. Reducing clinker content is also essential for lowering CO₂ emissions. Recent research supports this direction: a 2025 Springer publication demonstrated that calcined smectitic clay waste can partially replace Portland cement in LC3-type binders while achieving competitive compressive strengths, highlighting the potential of industrial waste as a viable supplementary material.
Initial findings from KTU researchers working at the interface of the textile and cement industries show that adding 1.5% of recycled polyester fibre derived from discarded clothing can increase concrete strength by 15–20% and significantly improve freeze–thaw resistance.
Textile ash significantly increases strength
Thermal treatment of textile waste at 300 °C in an inert environment produces carbon-rich granules with high calorific value. Their use as an alternative fuel could reduce reliance on fossil resources. However, as with other fuels, their combustion generates secondary waste – ash.
The mineral and chemical composition of ash varies depending on the type of fuel, which means its effect on the strength and durability of cementitious materials can differ widely. KTU studies have shown that textile ash can replace up to 7.5% of conventional cement and increase the compressive strength of cement samples by up to 16% under standard curing conditions.
“This technological solution not only reduces CO₂ emissions during cement production but also provides an innovative and environmentally friendly approach to textile waste management,” adds Dr Kubiliūtė. While the production of alternative fuels from textile waste is still in its early stages in Lithuania and elsewhere, the potential of this area is increasingly recognised.
The research described above is part of the project “Production of Alternative Fuel from Textile Waste in Energy-Intensive Industries (Textifuel)”, carried out by KTU and the Lithuanian Energy Institute.
Caption
The samples of cement containing textile ash
Credit
KTU
Journal
Journal of Thermal Analysis
Method of Research
Experimental study
Subject of Research
Not applicable
Article Title
Application of smectitic clay waste for limestone calcined clay cement production
New recycling method for textiles
A novel, non-toxic solvent makes it possible to recycle mixed-fiber textiles almost perfectly.
image:
Nika Depope in the lab at TU Wien
view moreCredit: TU Wien
We are producing more textiles than ever before: worldwide, well over one hundred million tons of textiles are manufactured every year – more than twice as much as in the year 2000. This makes it increasingly important not to simply throw away old textiles, but to recover them in an environmentally friendly way.
That is often not easy – especially when it comes to blended fabrics, such as mixtures of cotton and polyester. At TU Wien, a new method has now been developed to separate and recycle such mixed textiles efficiently – in a remarkably simple way, using menthol and benzoic acid, two non-toxic substances.
Five minutes is all it takes
“What may be surprising at first: both menthol and benzoic acid are solid at room temperature. But together they form a liquid – a so-called deep eutectic solvent. This novel liquid is a powerful, non-toxic and easy-to-produce solvent with a wide range of possible applications,” explains Andreas Bartl from the Institute of Chemical, Environmental and Bioscience Engineering.
When this new solvent is heated to 216 °C, a fascinating process begins: within just five minutes, the components of the mixed textiles separate from each other. The polyester dissolves completely, while the cotton remains unchanged. It can then be washed, dried and reused, and the polyester portion precipitates upon cooling, is separated, and can also be recycled. With recovery rates of 100% for cotton and 97% for polyester, the process achieves an almost complete recycling – a result that conventional methods have not been able to reach so far.
Separating, not breaking down
“The truly remarkable thing about this new process is that neither the cotton nor the polyester is damaged or chemically altered,” says Andreas Bartl. “Our analyses show that the cotton fibres remain stable and retain their typical properties – they can even be spun into new yarns again. And the polyester also remains unchanged: its structure and melting temperature are the same as before. This demonstrates how gentle and efficient this recycling process is.”
Until now, polyester has usually been chemically broken down during recycling, split into smaller molecular building blocks. The new method, by contrast, preserves the polymer chains intact – which means that the material quality is maintained.
A promising approach
So far, the process has only been tested in the laboratory, but the research team led by Nika Depope and Andreas Bartl sees great industrial potential in it. Both the recovered cotton and the recycled polyester can be used for a wide range of applications – for example for new yarns, fibres, nonwovens or technical textiles.
The team is currently working on making the process even more energy-efficient, since the required temperature of 216 °C is a drawback in terms of energy consumption. However, the researchers are confident that further optimisations are possible – and that the method could in future be used on an industrial scale.
Journal
Waste Management
Method of Research
Experimental study
Subject of Research
Not applicable
Article Title
Deep eutectic solvent as a solution for polyester/cotton textile recycling
