Innovative hybrid fiber-reinforced shotcrete for thin repairing concrete overlays

  • 1 Institute of Mechanics, Bulgarian Academy of Science, Sofia, Bulgaria


Shotcrete is a technology patented in 1911 by Dr. Carl Akeley – curator at the Field Columbian Museum in, Chicago. The system enables one to place a cement-sand mix or concrete on various surfaces via high pressure and casing by means of special equipment – a shotcrete machine. In fact, this is a method for concrete casting by pressure through a hose and pipe-lines at high velocity into the surface. Two basic methods of shotcrete exist – “dry” and “wet” ones. The report discusses the main technological features of the two methods, analyzing their advantages and disadvantages. Emphasis is placed on the possibilities of rational choice of one of the two varieties of technology depending on multiple factors of complex nature. In a synthesized way are presented their potential for carrying out specialized construction works – repair, reconstruction and strengthening of damaged reinforced concrete constructions, consolidation of rock massifs and slopes, construction of tunnels, swimming pools and other special facilities. The effectiveness of the “wet” method is based to real possibilities to involve in concrete mix design different chemical innovative admixtures – ultra high range water reducing (HRWRA), shrinkage compensating (ShCA), internal crystallization one, etc. Preliminary estimates are presented for their economic expediency under specific conditions.



  1. D. Bittner, Shotcrete: Wet process versus dry process, Concrete Repair Bulletin, July/August, 2015,
  2. European Specification for Sprayed Concrete, EFNARC, Association House, 99 West Street, Farnham, Surrey, GU9 7EN, U.K - ISBN 0 9522483-1-X,1996.
  3. J. Bertrand, Shotcrete Supply: Dry or Wet? A Shotcrete Supplier’s Perspective, Shotcrete, Spring, 2006.
  4. V. Naidenov, An innovative approach for repairing of corroded reinforced concrete industrial structures in aggressive environment by high-tech hybrid reinforced sprayed concrete with capillary crystalline admixture, MACHINES, TECHNOLOGIRS, MATERAILS (MTM), Year XIII, ISSUE 6/2019, ISSN PRINT 1313- 0226, (259-262).

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