Kazan scientists develop lightweight and durable construction material

Researchers from the Tupolev Kazan National Research Technical University (KNRTU-KAI) have developed a new lightweight and durable porous construction insulation material with a significantly more stable structure than existing geopolymer foams. The innovation has been protected by two Russian patents, as reported by the official website of the Ministry of Science and Higher Education of the Russian Federation.

Geopolymer foam materials based on aluminosilicates are widely valued in modern construction for their low weight, fire resistance, water impermeability and strong thermal and acoustic insulation properties. These characteristics make them especially suitable for sustainable and energy-efficient construction, where they can replace conventional insulation materials in buildings, aircraft and shipbuilding sandwich structures, as well as insulation panels.

Their resistance to salts and acids, due to the absence of calcium compounds, and the use of industrial waste such as fly ash and metallurgical slag in production further enhance their environmental appeal.

The Kazan research team addressed this challenge by developing stable compositions and a simple production technology for geopolymer foams with a density of 197–234 kg/m³. The resulting material demonstrates a uniform fine-cell structure and high mechanical strength, significantly expanding its potential applications.

Metakaolin was used as the primary raw material, containing 52 per cent silica and over 42 per cent aluminium oxide. An alkaline sodium silicate solution served as the activator, azodicarbonamide was selected as the foaming agent, and gum arabic – a natural, water-soluble resin stable at temperatures up to 250°C – was used as the foam stabiliser.

Based on experimental results obtained at different heating rates, the researchers designed a two-stage production process. It includes pre-foaming at 30°C for 10–15 minutes, followed by high-temperature foaming at 220°C for 20–30 minutes. This approach allows the production of lightweight yet mechanically robust aluminosilicate foam materials.

The team also produced prototype sandwich panels featuring an aluminosilicate foam core combined with carbon composite and mica-based facings using aluminophosphate matrices. Testing confirmed that these structures meet national standards for low-combustibility materials, reinforcing their suitability for advanced construction and engineering applications.

Photo: gorodenkoff / iStock