Influence of dispersed reinforcement on properties of road concrete obtained by vibropressing semi-dry mixtures

Abstract

Abstract. Problem and goal. The results of research of influence of dispersed reinforcement on properties of concrete semi-dry mixes, their ability to consolidation by vibropressing and strength characteristics of the received concrete are resulted. Metodology and result. In the first stage of research, steel anchor fiber was used as a dispersed fiber, the second stage was devoted to vibropressing mixtures with basalt fiber. In order to establish the influence of the parameters of the composition of vibropressed reinforced concrete and to obtain quantitative dependences of the main properties for their use in the design of the composition, a planned experiment was conducted. The regression equations for water consumption, average density of compacted concrete mixture, compressive strength and tensile strength during splitting at the age of 28 days were obtained. The analysis of the obtained equations showed that the dispersed reinforcement of concretes from semidry mixture with steel fiber is associated with a complicated distribution of fiber, which necessitates an increase in water content, the introduction ofincreased amounts of plasticizers. Vibropressed reinforced concrete has increased values of tensile strength in splitting and compression, which allows it to be recommended for the manufacture of road elements. It was found that basalt fiber is much better distributed during mixing and, unlike steel, less interferes with compaction. Disperse reinforcement of vibropressed concrete with basalt fiber allows to obtain values of tensile strength in bending within 10…13 MPa. This strength is 40…50% lower than when using steel fiber, but when vibropressing basalt fibers are more technological: improve the molding properties, provide greater homogeneity of concrete, allow to produce products with less wall thickness and any complex configuration. Originality. The obtained mathematical models of influence of factors of composition of vibropressed fibroconcrete on its mechanical and technological properties gave the chance to offer a way of designing of structure of such concrete with maintenance of a complex of necessary parameters and the minimum cost of components.