Scientists use textile ash to create extremely strong cement

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.