The effect of the thickness of the load-bearing layer of shotcrete on the strength characteristics of load-bearing structures

Introduction. This article examines international experience with shotcrete application in the construction industry. An analysis of the composition and application technology of the shotcrete mixture is provided. The development and production of molds for sample preparation is described. Samples were manufactured using the selected technology of wet shotcrete. The experimental studies were conducted in two stages: in the first stage, custom formwork was manufactured using additive technologies. In the second stage, testing of the experimental samples and analysis of the results were conducted in accordance with current regulations. The analysis of the results is presented in tabular and graphical formats. The effective thickness of the shotcrete load-bearing layer for the construction of engineering structures is determined.

Aim. To develop removable formwork for experimental studies of the thickness of the shotcrete load-bearing layer and study its effect on the strength properties of load-bearing structures.

Materials and methods. The experimental study was conducted in laboratory conditions using certified equipment in accordance with existing regulatory documents.

Results. A collapsible formwork design was developed for the laboratory samples with varying thicknesses of the shotcrete bearing layer creation, and a shotcrete mix formulation was selected. Based on the results, the strength of shotcrete samples with different thicknesses was compared. The bearing layer thickness for engineering structures was determined, and recommendations for the appropriate shotcrete layer thickness for linings, engineering structures, and civil buildings were provided.

Conclusions. A collapsible formwork design for experimental samples was proposed. The experience of the shotcrete application in construction was taken into account during testing. Analysis of the experimental data showed that shotcrete performs similarly to conventional concrete, as confirmed by test results on 18 shotcrete samples with varying thicknesses and complies with current standards. Taking into account the formulation studies conducted, additional testing is necessary for fiber-reinforced shotcrete.

1. Andreeva N.V. A new-generation system of fiber-reinforced shotcrete blocks for low- and mid-rise buildings. Manufacturing technology and design solutions [dissertation]. Rostov-on-Don, 2024, 178 p. (In Russian).

2. History of shotcrete in the mining. <i>Eurotech</i> [website]. URL: https://stroifak.ru/ (accessed: 09.25.2025).

3. Golova T.A., Magerramova I.A., Andreeva N.V. Production technology of non-autoclaved foam concrete, dispersed reinforced with modified fibers. <i>Vestnik Volgogradskogo gosudarstvennogo arhitekturno-stroiteľnogo universiteta. Seriya: Stroiteľstvo i arhitektura = Bulletin of Volgograd State University of Architecture and Civil Engineering. Series: Civil Engineering and Architecture</i>. 2020, no. 1 (78), pp. 126–135. (In Russian). EDN: TMDUOX.

4. State Standard 5578-2019. Slag crushed stone and slag sand of ferrous and non-ferrous metallurgy for concretes. Specifications. Moscow: Standartinform Publ., 2019. (In Russian).

5. State Standard 14613-83. Vulcanized fibre. Specifications. Moscow: Publishing House of Standards, 1989. (In Russian).

6. STO 15122014-2014. Concrete reinforced with structural synthetic polypropylene fibre DURUS S400, DURUS S500. Specifications. Saint Petersburg: NTB LLC, 2014. (In Russian).

7. Golova T., Mailyan L. Clustering of shotcrete technology from the position of a single system integrated approach. <i>Construction and Architecture</i>. 2022, vol. 10, no. 2, pp. 41–45. (In Russian). DOI: https://doi.org/10.29039/2308-0191-2022-10-2-41-45. EDN: YGFYOE.

8. SN 277-80. Instructions for the manufacture of cellular concrete products / Gosstroy of Russia. Moscow: SUE CDP, 2001, 47 p. (In Russian).

9. State Standard 12730.0-2020. Concretes. General requirements for methods of determination of density, moisture content, water absorption, porosity and water tightness. Moscow: Standartinform Publ., 2020. (In Russian).

10. State Standard 8829-2018. Prefabricated construction concrete and reinforced concrete products. Load testing methods. Rules for assessment of strength, rigidity and crack resistance. Moscow: Standartinform Publ., 2019. (In Russian).

11. Mailyan L., Golova T. Light concrete based on foam polyamidbe-tonic composition. <i>Construction and Architecture</i>. 2019, vol. 7, no. 1, pp. 70–75. (In Russian). DOI: https://doi.org/10.29039/article_5ca75fa9df9457.56609824. EDN: UPYPII.

12. SP 63.13330.2018. Concrete and reinforced concrete structures. General provisions. Updated version of SNiP 52-01-2003. Moscow: Standartinform Publ., 2019. (In Russian).

13. Ivanova T.A. Shotcret technologies for construction and reconstruction of buildings and structures. Cheboksary: Publishing House “Sreda”, 2024, 88 p. (In Russian).