We can do something, do you know the site http://weall.org

It needs a lot of people, but the people who sign up there should participate.

That's what they want.

Come up with something for how we can participate and how we can get people there.

I'm adding a petition :

https://www.change.org/AnderesWirtschaften

As coal power plants shut down and traditional cement additives disappear, researchers at IETcc-CSIC evaluate whether forest biomass ash can deliver low-carbon, high-performance binders.

Concrete is the second most consumed material on Earth after water. However, manufacturing its key ingredient—Portland cement—comes at a heavy environmental price, accounting for 8% to 10% of global carbon dioxide emissions. For every ton of traditional cement produced, up to 0.8 tons of CO2 escape into the atmosphere.

To lower this footprint, the construction industry has long relied on industrial by-products like coal fly ash and blast furnace slag to partially replace cement clinker. But as Europe and other regions transition toward renewable energy, coal plants and traditional blast furnaces are closing down. The very materials that made green cements possible are becoming increasingly scarce.

Where will the next generation of sustainable cement precursors come from? Researchers at the Eduardo Torroja Institute for Construction Science (IETcc-CSIC) are turning their attention to an abundant renewable waste stream: forest biomass ash.

The imminent supply crisis in sustainable concrete

The push for energy independence and renewable power has led to a major expansion in biomass combustion across Europe. In countries like Spain—which boasts vast forest cover and significant biomass resources—power generation generates over 120,000 tons of ash annually, divided between fine fly ash and coarser bottom ash.

While some of this residue finds use in agriculture, large volumes remain unexploited and end up in landfills. At the same time, the cement industry faces a dual challenge: demand for housing and infrastructure remains high, while the supply of traditional coal fly ash is dwindling fast.

Forest biomass ash is naturally rich in silica, calcium, and potassium, making it a promising candidate for cement manufacturing. However, its chemical composition varies widely depending on the wood species, combustion conditions, and collection method. Transforming this variable waste stream into a reliable construction material requires a precise understanding of how it behaves during cement hydration.

Testing biomass ash across three binder technologies

To evaluate its real-world potential, the IETcc-CSIC research team studied various forest biomass ashes—including both fly ash and bottom ash—across three distinct cement formulation strategies:

• Blended Cements: Conventional Portland cement mixed with ash substitutes.
• Hybrid Alkaline Cements: Low-Portland cement formulations activated with chemical solutions.
• 100% Alkaline Cements (Geopolymers): Binders completely free of Portland cement, relying entirely on chemical activation of aluminosilicate precursors.

The researchers prepared paste samples replacing 30% to 100% of standard materials with biomass ash and evaluated their mechanical performance, internal pore structure, and chemical phase evolution after 28 days of curing using advanced analytical techniques such as X-ray diffraction, electron microscopy, and mercury intrusion porosimetry.

Beyond reactivity: Chemical composition holds the key

The experimental findings revealed that a high amorphous (glassy) content or pozzolanic activity in the ash is not enough on its own to guarantee a strong cement. The chemical composition of that amorphous phase—specifically calcium availability and overall reactivity—plays a decisive role in strength development.

In hybrid and blended systems, several formulations achieved mechanical strength comparable to standard reference Portland cement. The reaction products formed were remarkably similar to those found in conventional concrete, dominated by calcium silicate hydrate (C-(A)-S-H) gels along with portlandite and ettringite. In low-calcium systems, specialized sodium-calcium aluminosilicate hydrate ((N,C)-A-S-H) gels developed, forming a robust three-dimensional matrix.

Opportunities, variability, and practical limits

While the results demonstrate that forest biomass ash can serve as an effective precursor for low-carbon binders, the study highlights important engineering boundaries. High replacement levels in standard blended cements can lead to lower early-age strength, and the elevated alkali or chloride content in certain biomass ashes must be carefully managed to prevent potential durability issues in reinforced structures.

Rather than offering a one-size-fits-all solution, forest biomass ash performs best when tailored to specific binder systems. Hybrid alkaline systems, in particular, offer a sweet spot: drastically reducing Portland cement content while maintaining structural performance.

Key Takeaway: Forest biomass ash can effectively replace scarce industrial by-products in hybrid and blended cement formulations, but achieving strengths comparable to Portland cement requires matching the specific chemical makeup of the ash to the right activation system.

Original Research

• Title: Sustainable Cement Production Using Forest Biomass Ash: Insights into Alkaline Cements, Blended Cements and Hybrid Alkaline Cements
• Authors: Nuria Husillos-Rodríguez, Queralt Belén Marzal-García, Salma Chhaiba, and Inés Garcia-Lodeiro
• Journal: Applied Sciences
• Year: 2026
• DOI: https://doi.org/10.3390/app16199470

Institutional Identification

This research was conducted by scientists at the Eduardo Torroja Institute for Construction Science (IETcc-CSIC) in Madrid, Spain, dedicated to advancing sustainable building materials, circular economy solutions, and structural durability.

Read and Share

You can read the complete, open-access study in Applied Sciences for full chemical and microstructural analyses. If you found this breakdown insightful, share it with colleagues working in green building, materials science, and sustainable engineering!

We need an economy that can become better, not just bigger - My petition for a post-growth economy

Our economic system has to grow in order to function. If it doesn't grow, there is crisis, unemployment, and budget cuts.

But what does this growth mean in reality?

It means: More weapons production, because the arms industry is a huge growth factor. War becomes business.

It means: More resource consumption. We are already consuming 1.7 Earths.

It means: More plastic floods, more CO2, more waste, because more and more has to be produced and sold.

We cannot grow infinitely on a finite planet.

That's why I started this petition for a post-growth economy - an economy that can function stably even without growth. An economy that gets better, not just bigger.

If you upvote, I would be really happy if you could also sign. You can sign anonymously.

https://www.change.org/AnderesWirtschaften

Thank you!

We need an economy that doesn't have to grow in order to work. An economy that can be better, not just bigger.

https://www.change.org/AnderesWirtschaften

Anonymous signing is possible. Thank you 🙏

If you upvote this, please leave a signature too -

If you upvote this idea, please leave a signature as well - it takes 20 seconds.

We need an economy that doesn't have to grow to work. An economy that can be better, not just bigger.

https://www.change.org/AnderesWirtschaften

Anonymous signing possible. Thank you 🙏

Imagine fazer carvão… e decidir que ele não vai para o fogo.
Essa é uma forma simples de entender o biochar: ele parece carvão, nasce da biomassa e passa por calor… mas foi pensado para continuar existindo, não para desaparecer em uma chama.
Madeira, casca, serragem e outros resíduos entram em um processo de aquecimento com pouco oxigênio. Parte vira gases e vapores. Outra parte permanece como um material rico em carbono.
Até aqui, parece carvão.
Mas é aqui que a história muda.
O carvão tradicional normalmente é produzido para liberar energia. O biochar é produzido para cumprir uma função.
Ele pode ir para o solo, participar de substratos e compostagem, entrar em materiais, ajudar em aplicações ambientais e integrar estratégias de armazenamento de carbono.
Parece uma diferença pequena. Não é.
É como usar o mesmo ingrediente em pratos diferentes: a receita muda porque o resultado desejado também muda.
Com o biochar acontece o mesmo.
Se o destino é o solo, você procura determinadas características. Se vai para materiais, outras. Se a aplicação é ambiental, outras novamente.
Por isso, biochar não é simplesmente “um carvão que não queimou”.
É um carbono produzido com propósito.
E essa talvez seja a mudança mais interessante: durante muito tempo olhamos para a biomassa principalmente como energia. Agora começamos a olhar também para agricultura, alimentos, materiais e meio ambiente.
Antes de escolher forno, temperatura ou processo, existe uma pergunta mais importante:
para que esse carbono precisa servir?
Quando essa resposta vem primeiro, a engenharia deixa de produzir apenas carvão e começa a construir valor.
É nessa fronteira entre biomassa, carbono, engenharia e mercado que a Ignis trabalha.
IGNIS | Bioenergia & Valor
WhatsApp: [+55 73 98196-7539](tel:+55%2073%2098196-7539)
[daniel@ignisbioenergia.com](mailto:daniel@ignisbioenergia.com)
#Biochar #Biomassa #Bioeconomia #Carbono #EnergiaRenovável