STRUCTURE, STRENGTH AND FRACTURE MECHANICS OF LIGHT CONCRETE BASED ON CLAYDITE OF THE REPUBLIC OF BELARUS

Abstract

The paper provides the experimental studies results of the aggregate characteristics effect on the strength and deformation properties of lightweight concrete. There is an analytical review of various researchers’ studies on this topic. The formation features of the lightweight concrete structure, the mechanics of its fracture, the features of the formation and microcracks development, and the basic principles for describing a complete deformation diagram are considered. It is extremely important in the production of structural lightweight concrete to observe the preparation technology of concrete mixture. It is also necessary to pre-wet the porous aggregate in order to avoid self-drying concrete. The porous coarse aggregate and dense fine aggregate (natural sand) are used to obtain structural lightweight concrete. The use of porous fine aggregate does not allow to obtain lightweight concrete with high strength. An increase in the coarse aggregate fraction negatively affects on the deformation properties of expanded clay concrete, and the water-cement ratio does not significantly affect either the strength or deformation characteristics. Assessment of the average particle diameter of the porous aggregate can serve as an indirect method for assessing the basic deformation characteristics of lightweight concrete. The density of expanded clay concrete has a significant effect on its deformation property, in particular, on the values of microcracking formation, which can be taken into account in the calculation. The density and porosity of lightweight concrete are inversely proportional.