China builds super-soft runway material that crumbles to save planes

Chinese scientists have developed an innovative ultra-light foam concrete, dubbed “marshmallow” concrete, designed to enhance runway safety by absorbing the energy of aircraft during emergency landings. Weighing only 12.5 lb/ft³ (about one-tenth the weight of standard concrete), this material crumbles in a controlled manner upon impact, effectively decelerating even large aircraft like the Boeing 747. Developed by the China Building Materials Academy (CBMA) in collaboration with the China Academy of Civil Aviation Science and Technology, the foam concrete is already implemented at 14 airports across China and has won a prestigious innovation award. This new material addresses limitations of traditional Runway End Safety Areas (RESAs), which often use sand, soil, grass, or water pools—each with environmental or operational drawbacks such as freezing, animal attraction, or instability. The foam concrete’s strength is carefully controlled within a narrow range (0.30 to 0.35 MPa) to ensure it crushes