Creep study of carcass composites reinforced with steel fiber of the Dramix type

Abstract

The results of a creep study of disperse-reinforced building composites made by carcass technology are presented. In the experiment, steel fiber «Dramix» type fiber was used as dispersed reinforcement, the content of which was 1…3 % by volume of the composite. The impregnation matrix was made on the basis of portlandcement and a superplasticizing additive of the brand Melflux 1641 F. In the creep test, the samples-beams were loaded according to a 4-point scheme. The level of load applied to the samples was 30, 50 and 70 % of the maximum values. An unreinforced carcass composite was taken as a control composition. The tests continued until the moment when the value of the deflection became constant. Based on the data obtained, graphical dependencies «relative deflection – exposure time» were constructed. On the obtained creep curves of carcass composites in the general case, four sections of the kinetics of deflection change can be distinguished: the initial section, in which an intense, almost linear, increase in deflections occurs; the curved section where the attenuation of the process of growth of deflections is observed; a linear section in which the increase in deflections is insignificant and has a quasi-permanent character; the final section, when the stabilization of the deflections occurs, and their values become constant. The minimum deflection values were obtained for an unreinforced carcass composite, and the maximum for composite reinforced with 1 % «Dramix» fiber. When the composition of the carcass composites contains 2–3 % fiber, a significant decrease in the deflections was observed, but their values were higher than that of the control composition. This is explained by the different load applied to the reinforced and unreinforced samples of carcass composites, as well as the positive effect of increasing the content fiber to 2–3 % on their bending strength and stiffness. The studied dispersion-reinforced carcass composites can be used for the manufacture of monolithic industrial floors, foundations and pavements, working under the influence of increased mechanical influences.