PSI - Issue 59

Volodymyr Dovbenko et al. / Procedia Structural Integrity 59 (2024) 702–709 Volodymyr Dovbenko et al./ Structural Integrity Procedia 00 (2019) 000 – 000

707

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25

σ c , М P а

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15

1

10

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ε с × 10

-5

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0

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100

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200

Fig. 4. Diagram of concrete deformation during a one-time loading of prisms of the first series: 1 - controlled; 2 – reinforced.

It should be noted that during the test of reinforced concrete, brittle failure occurred, just as for concrete without reinforcement. Exfoliation of the composition from the concrete was not detected. Polymer and concrete worked as one material. This is probably because the compressive strength of concrete is lower than the strength of the polymer itself. The polymer worked together under the load having filled the pores and microcracks of the concrete, as if restraining the deformations of the concrete. It served as a rigid clamp. Control samples - tensile prisms in 3 pcs were tested without reinforcement. The remaining prism samples in 3 pieces reinforced with a polymer composition were tested with a short-term one-time load. The average strength of the control concrete under a single load was f ctk, prism = 2.58 М P а . In turn, the strength of the reinforced concrete was f ctk, prism = 3.35 М P а , which increased the tensile strength of the control concrete by 23%. The tensile test of special prisms shows that a sample reinforced with a polymer composition increases tensile strength better than compressive strength. Electron microscopy was performed to study the structural features of concrete reinforced with a polymer composition. Electron microscopic studies of the effectiveness of impregnated concrete were carried out using an electron microscope-microanalyzer PEMMA-102-02, which scans the surface of samples using an electron beam. To improve the contrast of the image, the shading of the object was performed. The essence was that a thin layer of copper was sprayed on the chipped surface of the test sample. The structure of the control and reinforced concretes was studied on chipped particles of test samples – cubes of 100×100×100 mm size. An image of the concrete structure is presented in the example of control samples and samples reinforced with a polymer composition at magnifications of 100, 200, and 600 times (Fig. 5a,b). Concrete impregnated with a polymer composition has its characteristics. They consist of the fact that the composition is polymerized in its pores. In the polymerization process, the monomer decreases in volume and squeezes the mineral part of the material. At the same time, a certain amount of monomer can be evaporated before the completion of the polymerization. During the study of the chipped surface of concrete impregnated with a polymer composition of experimental samples was found (Fig. 5a,b) that a polymer mesh was formed in the pores of the cement stone. The composition seems to seal the defects of the concrete structure and bind different areas with thousands of threads, increasing their load and crack resistance. A concrete polymer mesh can be considered a type of dispersed reinforcement. As a result, the state of the material can be considered pre-stressed, which increases its strength.