CHINESE researchers have developed a revolutionary runway safety system using ultra-lightweight foam concrete, nicknamed “marshmallow” concrete, designed to gently halt hundred-ton class aircraft during emergency landings. The breakthrough was achieved by China Building Materials Academy (CBMA) Co., Ltd. in collaboration with the China Academy of Civil Aviation Science and Technology and a tech firm affiliated with the Beijing academy. It recently received the second prize for innovation from the China Building Materials Federation, according to Science and Technology Daily. The research team created a material resembling ordinary concrete but with over 80% porosity and a density of just 200 kilograms per cubic meter — about 1/10 the weight of standard concrete. This material forms a “soft barrier” that absorbs kinetic energy through controlled crushing. “It looks solid, but crumbles upon impact, decelerating planes easily,” explained Fang Jun, a CBMA engineer. Foaming is a crucial step in producing ultra-lightweight foam concrete. “The process is essentially ‘blowing bubbles’ into the concrete mixture,” Fang said. To strengthen the bubble films, the researchers introduced a maleated rosin-based twin-chain air-entraining agent. This agent allows molecules to densely align on bubble membranes, forming a robust “armor” that prevents material collapse. Takeoffs and landings are critical phases for aircraft safety, with accidents frequently occurring during these times. To reduce risks, the International Civil Aviation Organization (ICAO) requires runway end safety areas (RESAs) extending at least 90 meters beyond runways. Traditionally, RESAs have consisted of water pools, grass areas, soil, or sand — but these have been unstable and environmentally sensitive. (Xinhua) | 