Prediction of the resistance of steel fiber concrete to thermal effects at various parameters of dispersed reinforcement
The article presents the results of computational studies that are part of the authors' comprehensive research on the development of a methodology for predicting the resistance of steel fiber concrete to thermal effects at NPP facilities with various parameters of dispersed reinforcement. The studies were carried out using selected models to describe the processes of thermal deformations and changes in the most important properties of steel fiber based on previously obtained experimental and calculated data on thermal changes of steel fiber on an optimized cement-sand matrix with five types of steel fiber with a volume content of 0.5% to 6% after heating at 110-1100 oC. Based on calculations in accordance with the accepted hypothesis and the selected models, the dependences of thermal changes in the properties of steel fiber concrete relative to matrix changes from the calculated changes in linear dimensions due to the formation of cracks in the fiber concrete are established. The dependences of thermal changes in the linear dimensions of steel fiber concrete due to the formation of cracks on the ratio of the calculated unreliaxed tensile structural stresses in the matrix to the tensile strength of the matrix are established. Based on the performed studies, a method for predicting thermal deformations, changes in mass, linear dimensions due to the formation of cracks, strength, water resistance of steel fiber concrete, based on thermal deformations and changes in the properties of the matrix, parameters of dispersed reinforcement is formulated.