Lightweight Concretes on Hollow and Porous Aggregates

One of the directions of development of concrete science is the combination of positive qualities of heavy and lightweight concretes. The problem of optimizing the structural properties of heavy concrete and the thermal properties of lightweight concrete is solved in a large number of scientific papers. In Russia, the most popular structural lightweight concretes are those based on expanded clay aggregate. Recently, there has been experience in reconstructing bridges made of lightweight concrete on hollow microspheres. Over the past 10 years, the possibilities for producing lightweight concrete with increased strength have improved significantly. The paper presents models demonstrating the features of the formation of the structure of lightweight concrete on hollow and porous aggregates. The advantages and limitations are described for each of the aggregates for obtaining lightweight concrete with a given average density and strength. The described models show that it is advisable to use porous filler to obtain high-strength lightweight concrete with an average density of more than 1600 kg/m3, and hollow filler at ρlb<1600 kg/m3. The thickness of the filler shell becomes the determining factor in achieving the required specific strength of lightweight concrete