CoRncrete: A corn starch based building material (2017)
Researchers are exploring “CoRncrete,” a cornstarch-based binder mixed with sand as a potential low-carbon alternative to Portland cement, but early results reveal serious drawbacks: it degrades in water within a day and its life-cycle analysis shows a carbon footprint similar to conventional concrete. Commenters question its scalability and sustainability, noting global cement demand far exceeds possible starch supply and raising concerns about diverting food crops and arable land, much as with corn-based ethanol. Many see more promise in improving traditional concrete production, alternative designs, or other bio-based materials, while still valuing negative or inconclusive results for preventing future hype-driven “green” boondoggles.
Material properties and limitations
- Mix is mostly sand with cornstarch as binder; analogy drawn to how concrete is named by binder (cement) despite being majority aggregate.
- Reported compressive strength ~26 MPa: comparable to basic “driveway” concrete but far below high‑strength structural concretes (40–200 MPa).
- Major flaw: degrades partially or completely in water within about a day. Likely needs sealing; some doubt it could ever be a general building material.
- Not fire‑resistant due to organic binder; contrasted with Portland cement’s suitability for structural, fire‑rated applications.
- Biodegradability and susceptibility to ants/rodents are raised as further concerns for long‑term use.
Environmental impact and scalability
- Several comments note that, as currently produced, cornstarch has a life‑cycle carbon footprint similar to Portland cement, so there is no clear emissions win.
- Debate over how heating energy for curing was treated in the LCA; unclear assumptions about grid cleanliness.
- Global production constraints: even diverting all corn (and its starch fraction) might not cover a quarter of current cement demand, which is expected to grow.
Potential niches (space and temporary structures)
- Water‑solubility seen as a bug on Earth but potentially acceptable on the Moon/Mars, where there’s little liquid water and starch might piggyback on food production.
- Counterpoint: importing starch to the Moon is costly; space construction research tends to prefer in‑situ materials (regolith, ice).
- Historical parallels with “staff” and other temporary materials raise the idea of deliberately short‑lived or biodegradable architecture, though safety and replacement energy costs are concerns.
Comparisons with other low‑carbon approaches
- Other pathways to decarbonize concrete:
- Electrifying cement kilns and capturing kiln CO₂.
- Structural design that uses less concrete (optimized beams/floor systems).
- Alternative bio‑materials like mycelium, hempcrete, strawbale, bagasse boards, and advanced wood products, each with their own trade‑offs.
Food, land use, and biofuel parallels
- Strong concern about diverting food crops to materials, echoing earlier corn‑ethanol debates and food‑price impacts.
- Some argue there is global food surplus if waste and distribution were fixed or if ethanol corn were redirected; others stress topsoil and arable‑land limits.
Policy, economics, and greenwashing
- Many view cornstarch‑based materials as another potential outlet for overproduced, subsidized corn rather than a climate solution.
- Long digression into biofuels: multiple comments frame corn ethanol as farmer/agribusiness subsidy and “green” pretext, with government reports and propaganda cited on both sides.
- Broader skepticism toward “environmentally friendly” branding and subsidy‑driven boondoggles (e.g., solar roadways, offshore wind in some critiques).
Meta and research value
- Commenters appreciate that a peer‑reviewed paper with largely negative practical results exists; it sets expectations and makes future hype or crowdfunding schemes easier to scrutinize.
- The thread is generally glad to see experimental binders explored but treats corncrete as an instructive dead end or niche material rather than a general cement replacement.