"Meringue" concrete revolutionizes airport safety

A group of Chinese researchers has developed an innovative material dubbed "meringue concrete", an ultra-light foam concrete capable of safely stopping aircraft weighing hundreds of tons in the event of emergency landings. The system, already implemented at 14 airports in China, could radically change international standards for runway end safety areas (RESA).

• What is "meringue" concrete?

The new material has a density of only 200 kg/m³, a tenth of the weight of standard concrete, and a porosity of over 80%. Despite its solid appearance, the concrete crushes in a controlled manner upon impact, absorbing the kinetic energy of aircraft efficiently and gradually, without shocks that endanger passengers or the structure of the plane. "It looks solid, but it crumbles on impact, slightly slowing down the planes,” explained Fang Jun, a researcher at the China Academy of Building Materials (CBMA).

• Why is such a system needed?

The International Civil Aviation Organization (ICAO) requires the existence of safety zones at the end of runways to reduce the risk of runway overruns. Until now, these zones were made with water basins, sand or grasslands - solutions that are often ineffective or dangerous: Water basins freeze in winter and attract birds; Soils or grasslands vary depending on humidity and temperature, with unpredictable mechanical strength; Sand is difficult to maintain and ineffective in extreme weather conditions.

• Engineering precision and durable materials

The key to the efficiency of Chinese foam concrete lies in controlling the compressive strength within a very tight range: 0.30 - 0.35 MPa. Unlike traditional concrete, where higher strength is considered an advantage, in this case it is essential that the concrete fails in a controlled manner. "It is a material that works well precisely because it is weak - but in a controlled manner,” Fang Jun emphasized. To reduce costs, the researchers avoided using expensive calcium sulfoaluminate cement and developed a formula based on regular cement but strengthened with special additives.

The system has already been implemented at 14 airports in China, including Nyingchi, in the mountainous and humid Xizang region (Tibet). There, monitoring data from the first year showed a fluctuation of just 3% in the material's performance - significantly lower than the design limit of 10%. In addition, a special two-stage strength adjustment technology allows the material to adapt over time, compensating for wear caused by external factors such as humidity, UV rays and temperature variations.

The Chinese invention, which has already won a national innovation award from the China Building Materials Federation, has the potential to revolutionize international standards for airport safety. In addition, being more affordable, it could be a viable solution for regional airports and low-cost carriers, where resources for state-of-the-art infrastructure are limited. This innovation proves once again how materials engineering and applied research can contribute to increasing aviation safety - in an era where air traffic is constantly growing and the challenges of sustainability and resilience are becoming more pressing.