CONCRETE

UDC 691.328.44

Pukharenko, Yu. Dr. Eng. Sc., prof., Saint Petersburg State University of Architecture and Civil Engineering, Saint Petersburg

Akhmetov D. A. Doctor of Technical Sciences, General Director, NIISTROMPROJECT, Almaty, Kazakhstan

Morozov V. I. doctor of technical science, professor, Saint Petersburg State University of Architecture and Civil Engineering, Saint Petersburg, Russia

Kostrikin M. P. post-graduate student, Saint-Petersburg State University of Architecture and Civil Engineering, Saint-Petersburg, Russia

Alitinform №3 (64) 2021 г. 42-52 p.

Abstract

The processes of structure formation in cement systems without reinforcement and with low-modulus synthetic macro- and microfibers have been investigated. A comparison is made of the work of macrofibers and microfibers in a concrete matrix with a large aggregate. The influence of low-modulus synthetic fibers on the characteristics of strength, crack resistance and durability of building composites is estimated. It has been established that synthetic macrofibers have a predominant effect on the strength characteristics of the composite, increase crack resistance and fracture toughness, while synthetic microfibers modify the structure of the cement stone, improve the pore structure, and increase frost resistance and water impermeability of the composite. It has been substantiated and experimentally confirmed that by combining fibers of different standard sizes in one composite, it is possible to obtain a material with simultaneously high strength, durability and crack resistance. On the basis of experimental data, the efficiency of using synthetic fibers in the manufacture of PAG airfield slabs has been substantiated. Based on the calculation of the crack resistance of the PAG-20 slab, it was found that when reinforcing concrete with 0.9 % macrofibers and 0.2 % microfibers, it is possible to reduce the slab thickness by 14.5 % with a corresponding decrease in costs by 7 % per product.

Key words:

fiber-reinforced concrete, low-modulus synthetic fibers, macrofiber, microfiber, crack resistance