Mechanical Properties and Performance of Shotcrete Systems

Shotcrete systems, comprising pneumatically applied concrete with or without fibres, have become indispensable in civil and underground engineering owing to their rapid setting, excellent adhesion and adaptability to complex geometries. The mechanical properties of shotcrete span compressive strengths typically from 20 MPa to over 100 MPa, tensile strengths up to 10 MPa and flexural capacities that are strongly influenced by fibre type and dosage. Key performance indicators include early-age strength gain, post-peak ductility, toughness and rebound rate, all of which are determined by the cementitious matrix, accelerator chemistry and aggregate grading. Recent advances highlight the role of fine fillers and specialist accelerators in refining microstructure, accelerating ettringite formation and controlling setting times without compromising long-term durability. Fibre reinforcement, whether organic or steel, has been shown to enhance crack bridging, energy absorption and shear resistance, thereby improving overall service life in tunnelling, mining and slope stabilisation. Durability under aggressive environments—such as sulphate-rich waters or high ground temperatures—depends on accelerator choice and hydration products, which govern resistance to leaching, thermal damage and external chemical attack. Integrated approaches that combine optimised mix design, tailored accelerators and engineered fibres are now guiding best practices for sustainable, high-performance shotcrete across global infrastructure projects.

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Mechanical Properties and Performance of Shotcrete Systems publication trend

The graph below shows the total number of articles in mechanical properties and performance of shotcrete systems across all publications each year (not limited to Nature Index journals).

Technical terms

Shotcrete: Pneumatically applied concrete that is deposited at high velocity onto a surface, allowing rapid placement and high early-strength development.

Accelerator: A chemical admixture that drastically shortens setting time and promotes rapid strength gain, often by stimulating ettringite formation or aluminate hydration.

Ettringite: A needle-like hydrated calcium aluminate sulfate mineral that forms in early cement hydration, crucial for rapid set and initial strength but requiring controlled growth to avoid long-term expansion.

Rebound rate: The proportion of shotcrete material that bounces off the substrate during spraying, influencing material waste, surface density and fibre distribution.

References

1. Comparison of Effects of Sodium Bicarbonate and Sodium Carbonate on the Hydration and Properties of Portland Cement Paste. Materials (2019).
2. Polyamide Fiber Reinforced Shotcrete for Tunnel Application. Materials (2016).
3. Influence of liquid accelerators on shotcrete in karst area tunnels. Case Studies in Construction Materials (2022).