Imagine a runway that feels like a marshmallow under a plane’s wheels. That’s the vision behind a new ultra-light foam concrete developed by China Building Materials Academy (CBMA) and partners in Beijing. Dubbed marshmallow concrete, this material could reshape runway end safety areas (RESAs) worldwide.
Conventional RESAs rely on water pools, grass, soil or sand to slow overrunning aircraft. But weather extremes and maintenance can turn these barriers into hazards—frozen pools, animal hazards and unstable ground remain top concerns. Enter marshmallow concrete, a breakthrough with over 80% porosity and a density of just 200 kg/m3—only one-tenth the weight of standard concrete.
Soft Barrier, Strong Impact
The secret lies in controlled crushing. When a hundred-tonne jet like a Boeing 747 slides into the foam, the material crumbles in a narrow strength window of 0.30–0.35 MPa, absorbing kinetic energy and decelerating the aircraft smoothly. According to Fang Jun, a CBMA engineer, the structure looks solid but gives way under impact, creating a cushioned stop.
Innovation Meets Affordability
While some designs use calcium sulfoaluminate cement for rapid hardening, high costs and long-term powdering make them less practical at small airports. The Beijing team opted for ordinary cement, cutting costs without sacrificing durability. A tailored foaming process—think blowing bubbles into the mix—creates a sturdy bubble matrix using a maleated rosin-based twin-chain air-entraining agent that fortifies the bubbles like microscopic armor.
Built to Last Outdoors
To combat weather-induced wear, the researchers developed a dual-stage strength-regulation technology. This staged-release mechanism compensates for environmental factors, keeping the foam’s protective power consistent over years of exposure.
Awarded by the China Building Materials Federation, marshmallow concrete promises a leap forward for aviation safety. For global citizens, tech enthusiasts and sustainability advocates, it’s proof that even the toughest challenges can yield to light, airy innovation.
Reference(s):
Scientists create 'marshmallow' concrete to stop aircraft safely
cgtn.com
