Revolutionary Foam Concrete Enhances Runway Safety for Aircraft Emergencies

Researchers in China have made significant progress by inventing a groundbreaking runway safety system that employs a new type of ultra-lightweight foam concrete, affectionately named "marshmallow" concrete. This innovative material can safely halt massive aircraft during emergency landings by creating a soft barrier that absorbs kinetic energy through controlled crushing mechanisms.

Produced by the China Building Materials Academy in collaboration with other aviation and technology institutes, this foam concrete boasts over 80 percent porosity and weighs only 200 kilograms per cubic meter—approximately a tenth of the weight of traditional concrete. Fang Jun, an engineer from the China Building Materials Academy, described how this material appears solid yet disintegrates upon impact, enabling a smoother deceleration process for landing planes.

Takeoffs and landings are crucial moments in aviation, known for their potential risks. The International Civil Aviation Organization mandates the implementation of runway end safety areas (RESAs), which should extend at minimum 90 meters beyond the runway. Traditionally used materials for these areas have included water, grass, or soil; however, these options can be problematic due to environmental variability and instability.

Fang noted that while conventional methods might lead to freezing or animal attraction in water pools, and soil can be susceptible to moisture and temperature changes, the newly developed foam concrete maintains consistent mechanical properties and performance. Its ability to absorb energy through a controlled fracturing process was a key focus during its development, aiming to keep the strength within a narrow range for optimal safety.

Unlike international techniques that often utilize calcium sulfoaluminate cement, which can be costly for smaller airports, the researchers prioritized creating a more affordable yet resilient solution using ordinary cement. The foaming process, which involves incorporating bubbles into the concrete mixture, was enhanced with a novel air-entraining agent that fortifies the bubbles, preventing collapse.

To ensure the longevity of this arrestor system in outdoor conditions, the team established a dual-stage strength-regulation technology that effectively controls the material's strength development over time. This approach tackles any potential degradation due to environmental factors. Currently, the foam concrete has been applied across 14 airports in China, with performance data from the Nyingchi airport indicating remarkable stability, well within safety design tolerances.