Mikhail Zhavoronkov, Associate Professor at the Department of Technology of Construction Materials and Metrology, completed the research work “Development of methods for constructing and processing diagrams of deformation of fiber-reinforced concrete under load” as part of a grant competition for the implementation of research work by scientific and pedagogical staff of the St Petersburg State University of Architecture and Civil Engineering in 2023

During the research, a sensor of an original design was developed that allows more accurate control of the fiber-reinforced concrete samples behavior under load. This is important for determining the power and energy characteristics values of the crack resistance of fiber-reinforced concrete.

Fiber-reinforced concrete has a number of advantages over traditional concrete and reinforced concrete. According to various sources, fiber-reinforced concrete is distinguished by increased compressive and bending strength, resistance to impact, etc. One of the main advantages of fiber-reinforced concrete is its increased crack resistance - the ability of the material to resist the formation and development of cracks.

Crack resistance can be expressed numerically through strength and energy characteristics, which are defined experimentally. The standard test method requires the use of specific equipment and is quite labor-intensive, so the results of such studies are probably sparse in the literature. Conducting research and accumulating statistical and reference data seems especially relevant. As a result of such studies, statistical data continues to accumulate and the problem of their paucity is gradually being solved.

The data obtained during the study can be used in the design of fiber-reinforced concrete structures and form the basis for further research, and the mastered test methods are implemented during the educational process as part of laboratory work in the relevant disciplines.

Work in this area has been carried out at the SPbGASU Department of Technology of Construction Materials and Metrology for decades. Many tests have been carried out to develop new or improve existing equipment and techniques. Mechanical devices, equipment based on analogue electronics, and later digital devices were developed and tested specifically for such tests.

“We tried to assemble devices connected to a standard laboratory press, and also assembled independent installations. Each time it was possible to achieve greater accuracy of the data obtained,” notes Mikhail Zhavoronkov.

One of the most successful developments is shown in Fig. 1. This is an installation created specifically for testing the crack resistance of fiber-reinforced concrete according to GOST 29167-2021. In addition, the figure shows the model of the installation used in its assembly and the sample being tested. The installation includes a mechanical loading device and a sensor system to monitor the behavior of fiber-reinforced concrete samples under load. Sensor readings are displayed on a computer monitor in the form of test results.