МЕХАНИЧЕСКИЕ СВОЙСТВА ФИБРОБЕТОНОВ ПРИ ДИНАМИЧЕСКОМ СЖАТИИ

Abstract

The article discusses the results of an experimental study of high-speed deformation and destruction of four types of concrete under dynamic uniaxial compression. The introduction presents an overview of experimental studies of domestic and foreign authors of the dynamic properties of fiber-reinforced concrete. World practice confirms the expediency of introducing metal fibers into concrete in order to increase its strength dynamic properties. However, the combination of steel and polymer fibers has not been fully studied and is of current interest. Fine-grained concrete, steel fiber-reinforced concrete, polyfiber-reinforced concrete and combined fiber-reinforced concrete were tested at high-speed deformation. According to the results of the study, static and dynamic tests were carried out. Dynamic compression tests were carried out using the Kolsky method at strain rates from 102 to 103 s–1. Static tests were carried out on a hydraulically driven unit. To visualize the process of dynamic deformation and fracture, a high-speed FASTCAM Mini UX100 camera was used. The paper presents the compositions of the studied materials, test parameters, as well as a comparative analysis of the data obtained. The introduction of a reinforcing fiber into the original fine-grained concrete increased the dynamic strength of the material. In static tests, concrete with steel fibers and concrete with a combination of polymer and steel fibers showed close values for maximum strength. The highest strength under dynamic uniaxial compression was shown by fiber-reinforced concrete with steel fiber. The dependences obtained demonstrate that the maximum fracture stresses achieved in the experiments increase linearly with the growth of the strain rate and the corresponding limiting strains, while the time before the onset of fracture decreases according to a power law.