Modified Fiberboard for Monolithic Beams

The results of developing a fiber-reinforced concrete composition modified with multi-walled carbon nanotubes (MWCNTs) for application in monolithic beams are presented. A comparative analysis of six concrete compositions with various combinations of modifying components was conducted. It was established that the complex modification of concrete with steel fiber, superplasticizer "Polyplast SP-3" (1.5 % by cement weight), and MWCNTs (0.0005 % by cement weight) provides an increase in compressive strength by 84.4 % and flexural strength by 2.48 times compared to the control composition. The application of the developed composition allows increasing the strength class of structures from B27.5 to B50 or reducing the consumption of bar reinforcement by 19.2 %. A synergistic effect of the three-component modification system was revealed, attributed to the reduction of water-cement ratio, densification of the cement matrix at the nanoscale, and effective absorption of tensile stresses by the fiber.