Cement built the modern world, but it also quietly helped heat the planet. As researchers race to cut emissions from construction, a new generation of materials is emerging that does more than reduce harm, it promises to lock away carbon, reuse waste and even grow itself. The boldest claim is simple and provocative: for some projects, we may finally be able to say goodbye to cement.
From carbon negative “biological concrete” to structural blocks made of soil and cardboard, the lab bench is suddenly crowded with contenders. I see a pattern in these breakthroughs, not a single silver bullet but a portfolio of materials that together could rewrite how we build, if regulators, builders and investors move fast enough to test them at scale.
The carbon problem cement can no longer outrun
Portland cement has long been the backbone of concrete, and with it, of highways, apartment towers and dams. It is also one of the most polluting industrial products on Earth, responsible for hundreds of kilograms of carbon dioxide for every ton produced, a burden that now clashes directly with national climate pledges and corporate net zero targets. Researchers behind a new carbon negative binder explicitly contrast their process with conventional concrete that emits around 330 kilograms of CO2 per cubic meter, a reminder of how deeply emissions are baked into the status quo.
That pressure is driving a wave of experimentation that goes beyond tweaking existing cement recipes. Some teams are designing binders that do not emit carbon at all during production and instead trap it permanently within the material, turning buildings into long term storage. One such fast acting, long lasting material is described as a new option that does not emit carbon and instead traps it, signaling a shift from mitigation to active removal. In parallel, catalogues of Popular Cement Substitutes now highlight industrial byproducts such as Fly Ash, rich in silicon dioxide and calcium oxide, as partial replacements that can cut the clinker content of concrete while reusing waste from coal fired power plants.
Biological concrete and enzyme built stone
Among the most striking developments is a family of materials that behave more like living systems than inert rock. Researchers working on a new Enzymatic Structural composite in the United States have created a carbon negative building material that uses enzymes to bind aggregates at low temperatures, avoiding the fossil fuel intensive kilns that define cement production. The process is described as bioinspired, with low energy demand, and the resulting blocks are pitched as a potential replacement for concrete in some structural applications.
In parallel, scientists have reported a Biological Concrete that Heals Itself and Is Carbon Negative, using microbial activity to both strengthen the material and repair cracks over time. The same research underscores the scale of the challenge, noting that we live in the age of concrete and that traditional cement production emits roughly a ton of CO2 per ton of product. I see these biological and enzyme based approaches as early but important signals that structural materials can be grown or assembled under gentle conditions, rather than baked in kilns that lock in emissions for decades.
Turning soil, water and cardboard into structural walls
Not every alternative relies on exotic chemistry. At RMIT University in Australia, a group of researchers set out Facing the cement issue by asking how far they could go using local soil, minimal processing and recycled waste. Their answer is a new building material made entirely from soil, water and recycled cardboard that eliminates the need for cement in certain applications, according to RMIT reporting. Separate coverage notes that Researchers have developed this soil, water and recycled cardboard mix into a structural material, positioning it as a low carbon option for walls and columns.
The concept has been pushed further by architects and engineers experimenting with cardboard confined rammed earth. In this system, cardboard tubes serve as both mold and reinforcement, filled with compacted earth that hardens into durable structural columns. Advocates describe how these tubes, once filled, reduce waste and cut reliance on high emission materials, with one analysis noting that Once the earth is compacted, the tube remains as permanent formwork. A separate overview explains that Cardboard confined rammed earth combines soil, water and cardboard tubes or moulds to create walls suitable for low rise construction, and that unlike conventional rammed earth, no cement is required. In a social media explainer, the project is framed as TURNING TRASH INTO TREASURE Led by Dr. Jiaming Ma, who uses cardboard tubes as molds to compress a soil oil water mix, turning junk into strong, reusable building blocks.
Ferrock and the rise of waste based stone
If soil and cardboard represent one path away from cement, industrial waste offers another. Ferrock has emerged as a particularly intriguing candidate, an environmentally friendly alternative to concrete made from waste steel dust and silica from ground up glass. One overview of sustainable materials notes that Ferrock is produced from these waste streams, turning what would otherwise be landfill into a structural binder.
The backstory is almost accidental. The History of Ferrock began when Dr David Stone, founder of Iron Shell Me, stumbled on the material in the early 2000s while working with iron rich waste. Subsequent testing has shown that Ferrock has been proven to be stronger than concrete in compression and offers much more flexibility as well, properties that matter for earthquake resilience and long span structures. A separate report describes how a researcher accidentally discovers material that is stronger and more flexible than concrete, noting that it is made from steel dust that is usually thrown out and silica from pulverized glass, and that 95% of the materials that make Fer are recycled. The same account stresses that this discovery could help traditional concrete give way to greener alternatives, a clear signal that waste based binders are moving from curiosity to serious contender.
From niche experiments to mainstream building codes
For all the excitement, I see a hard truth running through the data: no single material is ready to replace cement everywhere, from skyscraper cores to offshore wind foundations. Instead, the near term future looks more like a patchwork of regionally appropriate solutions. In some climates, green concrete that swaps a portion of cement for industrial byproducts will dominate, while in others, soil based systems and biological binders will make more sense. A technical guide to Green concrete and other alternatives notes that these mixes can cut embodied carbon but may be harder to plaster or finish, trade offs that designers will need to weigh.
At the same time, the pipeline of options is thickening. One consumer facing explainer on eco friendly materials reminds readers that this is not the first time scientists discovered concrete substitutes, pointing to Montana State University researchers who invented an ultra hard alternative and describing how the hollow tube is full of compacted material in some systems, a nod to the way Montana State University and others are rethinking formwork. Meanwhile, a separate analysis of a new carbon negative building material emphasizes Bioinspired Production With, reinforcing the idea that future standards will judge materials not just on strength and cost but on energy use and carbon balance across their life cycle.
Even within the cement industry, the shift is visible. Compilations of Popular Cement Substitutes now sit alongside traditional product lines, and major producers are investing in fly ash, slag and other supplementary cementitious materials to stay ahead of regulation. In that context, the new wave of biological, enzyme based, soil and waste derived binders looks less like a fringe movement and more like the research and development arm of a sector that knows it must change. Whether we truly say goodbye to cement or simply demote it from default to one option among many, the direction of travel is clear, and the next decade of building will be shaped as much in the lab as on the construction site.
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