Researchers at the Jagiellonian University have developed a method to enhance the natural ability of building materials to bind carbon dioxide from the atmosphere. The method relies on an easily accessible material that is, in fact, a waste product. This offers an opportunity to reduce the cost of building materials while increasing the likelihood that the new solution will be adopted on an industrial scale.
According to scientists from the Jagiellonian University, the solution has clear industrial potential. The environmental effect sought by the construction sector can be achieved using a readily available waste material—ash from incinerated sewage sludge produced at wastewater treatment plants. In the future, this could become a simple and efficient method of reducing the carbon footprint of the construction sector while ensuring responsible waste management. The new solution may also lower material costs, further boosting its implementation potential.
The research was conducted by Prof. Monika Kasina and Adam Wierzbicki, MSc.
Sewage Sludge Ash (ISSA)
The innovation involves the use of Incinerated Sewage Sludge Ash (ISSA), classified as a non-hazardous waste. It is important to emphasize that both sewage sludge and ISSA must be processed and disposed of. The newly developed method therefore turns a problematic waste material into something useful. Using ISSA not only reduces the amount sent to landfills but also lowers the demand for pure cement in building material production. This can translate into reduced CO₂ emissions from cement production. Another advantage is that ISSA is generated year-round in stable quantities, ensuring a reliable supply of raw material for the method.
ISSA is produced by incinerating dewatered sewage sludge at temperatures of around 900°C in specialized fluidized-bed furnaces. It has a stable and repeatable mineral composition, making it safe for use as an additive to cement-based building materials. ISSA contains a rich mineral profile, including carbonate, silicate, and phosphate phases rich in calcium, which contribute to natural carbonation processes.
When ISSA is added to cement in the appropriate proportion, the cement’s ability to bind atmospheric CO₂ increases, forming well-crystallized calcium carbonates (CaCO₃). These carbonates fill the microstructure of the cement, reducing its porosity and permeability. Importantly, adding ISSA does not disrupt the setting and hardening processes, which was confirmed in technological property tests.
Environmental and Industrial Benefits of Using Waste
“ISSA offers new possibilities for enhancing natural carbonation in cement-based materials. In properly selected proportions, it supports the process of binding carbon dioxide from the air. This solution clearly fits the principles of the green economy and corporate social responsibility, as it enables the rational use of industrial waste in a way that benefits both the environment and the construction industry,” explains Prof. Monika Kasina of the Jagiellonian University.
She adds that cement-based materials enriched with ISSA maintain their performance and quality parameters, as confirmed in laboratory studies.
“We have been working with a concrete manufacturer for a year. Together, we carried out experimental research and tests on mortars containing various shares of ISSA, checking compressive strength and other technological parameters. After six months of testing, the results show that all required technological parameters are maintained,” says Adam Wierzbicki, co-creator of the new cement enhancement method.
The key factor for implementation is the economic advantage. By adding ISSA to cement mixtures, less pure cement is needed. This reduces the consumption of primary raw materials (lowering the carbon footprint) and can also lower material costs—providing a competitive edge either through higher margins or lower product prices.
Less CO₂ in the Atmosphere Through Natural Carbonation
Studies show that cement-based materials enriched with ISSA bind significantly more CO₂ than those without the additive. Calculations indicate that bound CO₂ content was on average 24 kilograms higher per ton of material than in reference samples without ISSA. Laboratory analysis also revealed a 13–16% increase in calcium carbonate content after carbonation. The rate of this process is influenced by various environmental factors.
“The effectiveness of carbonation depends on environmental conditions—primarily air exposure, temperature, and humidity fluctuations. The best results occur in moderate, warm climates where cyclical humidity changes support the formation of well-crystallized, stable calcium carbonates,” adds Prof. Kasina.
For this reason, cement-based materials containing ISSA are best suited for elements exposed to the atmosphere, such as plasters, floors, stairs, and decorative components. Due to accelerated carbonation, these materials are not recommended for reinforced concrete structures, where higher CO₂ levels could increase the risk of steel corrosion.
Time for Technology Transfer
The method developed at the Jagiellonian University has been filed for patent protection. The CITTRU Technology Transfer Centre, responsible for commercialization, is seeking industry partners interested in further developing the technology.
“The method should undergo additional testing to thoroughly evaluate the long-term performance of materials containing ISSA. The research team plans such experiments, but we would like to carry them out together with industry partners. Licensing or even selling the rights to the technology to a construction company is one possible pathway,” says Dr. Gabriela Konopka-Cupiał, Director of CITTRU.
Searching for Green Innovations
One of the key strategies for combating climate change is the introduction of new solutions in the construction industry. Globally, extensive research is underway to develop technologies that reduce CO₂ emissions in material production. The work carried out at the Jagiellonian University aligns with this trend, offering an approach that combines waste recycling, carbon footprint reduction, and durability of cement-based materials.
A crucial factor in the adoption of such technologies is cost: innovative cement and concrete must be producible at relatively low cost. This increases the likelihood of widespread industrial use, as the resulting materials remain price-competitive.
About the Jagiellonian University
The Jagiellonian University (UJ) is the oldest university in Poland and one of the oldest in Europe, founded in 1364 by King Casimir the Great. For over 650 years, it has educated generations of students, scholars, and public leaders. Located in Kraków, Alma Mater Jagiellonica combines centuries-old academic tradition with modern approaches to research, teaching, and innovation.
UJ comprises 16 faculties and offers programs in more than 80 fields of study, including humanities, social sciences, natural sciences, medicine, and technical disciplines. The university consistently ranks among top national and international institutions, with notable alumni such as Nicolaus Copernicus, John Paul II, and Wisława Szymborska.
The Jagiellonian University is a major center of scientific research and innovation. Through its Technology Transfer Centre (CITTRU) and special-purpose companies, it supports commercialization of research results and fosters collaboration with industry. It also conducts numerous international projects in cooperation with leading universities worldwide.
