Lightweight Concretes Based on Glassy Aggregates are the Future of Envelope Structures

The paper discusses physical and mechanical, and heat-insulating properties of lightweight structural and insulating concretes based on various glassy aggregates – quenched cullets. Quenched cullet represents a fired aggregate that has a bulk density equal to 150-300 kg/m3 and cylinder strength of 0.5-2 MPa, which has been produced by pretreatment of silica rocks with an alkali component followed by firing in rotary kilns. It has been established that the aggregate grain's glassy envelope has a closed, evenly distributed porosity with a high content of the glass phase and improved strength and thermal and physical characteristics. Influence of the glass phase as part of a porous aggregate on the totality of concrete properties - structural, thermal and hydrophysical - has been found. Process fundamentals and standardization support for practical application of lightweight concretes featuring density D500-800 kg/cm3 and strength grades B2.5-7.5 in envelope structures with high heat-insulating properties have been developed.