For sprayed tunnel shotcrete, fibers often have the potential to reduce rebound compared with steel mesh because they are mixed throughout the concrete rather than creating a surface grid that can intercept and deflect the spray. However, fiber does not guarantee lower rebound: mix design, spraying technique, substrate, and fiber type all affect the result. Steel mesh may still be required where the design calls for discrete reinforcement, support for irregular ground, or a specific structural arrangement.
The fairest choice depends on the project’s measured rebound and engineering requirements—not on reinforcement type alone. Compare the options using the same shotcrete mix, equipment, nozzle operator, and site conditions, and verify that either system meets the project specification. The guidance below explains how to make that comparison and what buyers should confirm with suppliers.
Rebound is the portion of sprayed material that fails to adhere to the receiving surface and falls away during application. It may include cementitious material, aggregate, and reinforcement fibers, depending on the mixture and spraying conditions. Rebound is both a material-efficiency concern and a quality-control issue: material that does not remain in place cannot contribute to the installed lining.
Projects commonly express rebound as a percentage of the material discharged or sprayed, but the chosen collection and calculation method should be agreed before testing. For example, a project can report rebound as the mass of collected rebound divided by the mass of material discharged, multiplied by 100. Results are only comparable when the measurement method, test area, and operating conditions are consistent.
Fibers are dispersed through the shotcrete mix and can help control cracking and provide post-crack reinforcement, subject to the fiber type, dosage, and design requirements. Because there is no mesh grid in front of the receiving surface, the spray is not required to pass through mesh openings. That can reduce one source of rebound and help the operator apply shotcrete continuously across the surface.
Fiber performance is not automatic. Fiber type and dosage affect mix handling, pumping, workability, and the finished layer, while poor spraying technique or an unsuitable mix can still produce substantial rebound. As an indicative specification example rather than a universal recommendation, steel fibers may be offered in lengths around 25–60 mm; the appropriate length and dosage must be checked against the equipment, mix, and project design.
Steel mesh is fixed to the tunnel surface before shotcrete is applied. It provides a defined reinforcement layout and may be specified for design, installation, or ground-support reasons. Its effectiveness depends on correct installation and on shotcrete adequately filling around and behind the mesh without leaving voids.
The mesh can obstruct the spray path, especially where it is close to the substrate, overlaps, or has a complex arrangement. Material may strike the wires and rebound, but the amount is influenced by nozzle angle, distance, pressure, and application sequence. For context when reviewing quotations, mesh specifications may describe wire diameter and grid spacing—for example, a project might compare 6–10 mm wire and 100–200 mm spacing. These are illustrative dimensions only; they are not a design recommendation.
With competitive price and timely delivery, BEKA sincerely hope to be your supplier and partner.
| Factor | Fiber-reinforced shotcrete | Shotcrete over steel mesh |
|---|---|---|
| Rebound considerations | May avoid rebound caused by spray striking a mesh grid; outcome remains mix- and application-dependent. | Mesh can intercept the spray, particularly at wires, overlaps, and poorly covered areas. |
| Reinforcement arrangement | Distributed through the mix; performance depends on fiber specification, mixing, and dosage. | Fixed and visible layout; placement and attachment must follow the design. |
| Installation workflow | Can reduce or avoid a separate mesh installation step when the design permits. | Requires mesh handling, fixing, and coordination with spraying work. |
| Key quality concern | Uniform fiber distribution and shotcrete mix compatibility. | Coverage behind and around the mesh, plus correct positioning and fixing. |
| Best evaluated by | Design review, mix and pumping checks, and a controlled spraying trial. | Design review, installation inspection, and a controlled spraying trial. |
If the comparison is specifically about avoiding rebound caused by spray hitting reinforcement, fiber has a practical advantage because it is incorporated into the shotcrete rather than installed as a surface grid. That does not establish that fiber will always deliver a lower total rebound rate. Aggregate grading, water content, accelerator use, substrate condition, nozzle angle, and operator technique can all affect how much material adheres.
Mesh may remain the better or required option where the design specifies it, where a fixed reinforcement arrangement is needed, or where the project’s support method depends on mesh installation. Fiber may suit applications where the engineering design accepts fiber reinforcement and the project wants to simplify placement. In some projects, the design may require a combined approach; buyers should not remove mesh or substitute fiber without approval from the responsible engineer.
A single trial should not be treated as a universal performance guarantee. If conditions vary significantly between tunnel sections, repeat the comparison under representative conditions and preserve the test records. This gives the buyer and engineer a more useful basis for evaluating material efficiency alongside reinforcement performance.
Purchase price alone does not show which system is more economical. A mesh option may involve separate material handling and fixing work, while a fiber option can affect shotcrete batching, mixing, and pumping requirements. Compare the installed process, expected material use, labor, equipment compatibility, and quality-control requirements using project-specific quotations and trial results.
When requesting a quotation, provide the tunnel application, reinforcement design, required material grade, dimensions or fiber specification, quantities, delivery location, and any inspection or documentation requirements. Ask suppliers to identify what is included in the offer and to confirm production or delivery timing for the specified product. Avoid comparing prices where product dimensions, material requirements, or delivery terms differ.
Fiber often has the advantage when the goal is to avoid rebound caused by shotcrete striking a steel mesh grid, but it cannot be assumed to reduce total rebound in every tunnel. Mesh remains appropriate where the design requires a fixed reinforcement layout, and fiber is suitable only when its use meets the project’s engineering requirements. The most reliable answer comes from an approved, controlled comparison that measures rebound and checks the finished application.
As a next step, confirm the permitted reinforcement options with the project engineer, define a consistent rebound measurement method, and request comparable product quotations. BEKA can discuss stainless steel product requirements and sourcing considerations for buyers evaluating steel mesh options. Share your specification, dimensions, quantity, and delivery needs so the team can assess the appropriate supply scope.
If you want to learn more, please visit our website Tunnel Reinforcement Fiber vs Steel Mesh: Which Reduces Rebound Loss.