Research of lightweight monolithic reinforced concrete slabs with the use of plastic inserts

Abstract

The paper presents technology for installation of floor slabs lightened with plastic inserts which are preliminary stressed under construction conditions. Efficiency of such constructive solution is determined by the action of preliminary concrete compression in the tensile zone while reducing structure dead weight due to voids arrangement. Floor slabs of prestressed reinforced concrete in comparison with unstressed concrete have considerably smaller deflections and increased crack resistance, having the same strength, which allows to cover large spans with an equal section of the element. The resulting ratios of the slab thickness, the consumption of concrete and reinforcement in the girderless monolithic reinforced-concrete framework, depending on the span length of the frame building, show the advantage of using prestressed reinforcement rather than conventional. To lighten the construction of the floor slabs, a variety of shaped plastic inserts are proposed to use. The main requirements for materials and products for the making voids in the body of the construction and prestressing of the slab reinforcement are given. Analysis of technical and economic indicators of effective design solutions allows us to conclude that they are used for building spans, when using monolithic reinforced concrete slabs with unstressed concrete is impossible.