PARAMETRIC RESEARCH OF RESTRAINED STRAINS AND STRESSES OF SELF-STRESSED FIBER-REINFORCED CONCRETE AT THE STAGE OF EXPANSION

Abstract

One of the main advantages of self-stressed concrete is its ability to compensate for one of the main disadvantages inherent in mineral binders – shrinkage strains. However, approaches to predicting the properties of self-stressed concrete are not universal, since they are based mainly on phenomenological approaches and empirical dependencies. The main approaches to predicting strains and stresses arising in expansive concrete are energy- and deformation approaches. A number of researchers confirm the effectiveness of applying the deformation approach to determine intrinsic strains and stresses. Modification of the model for determining its own stresses and strains made it possible to move from the case of uniaxial bar reinforcement to two- and three-axis-limited elements. Based on the provisions of the deformation approach, a deformation model was proposed to determine the intrinsic strains and stresses of self-stressed fiber-reinforced concrete. The main prerequisites and assumptions of the proposed model are formulated. A block diagram of the algorithm of the iterative procedure is given, which makes it possible to calculate the intrinsic strains and stresses of self-stressed fiber-reinforced concrete. Parametric studies of self-strains and stresses of self-stressed fiber-reinforced concrete at the stage of expansion were carried out. The normalized dependences of the bounded strains on the varied parameters are presented. The area of effective use of steel fibers to achieve "binding" effect of free expansion in self-stressed concrete of different energy-activity has been determined. Influence of change of introduced fiber amount on development of bound strains of self-stressed concrete at different time intervals has been determined. The obtained results can be used in design, educational and research institutions.