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Innovative FRP solution for efficient tunnel excavation

ASTEC™ FRP Combination Bolt is a unique and innovative Glass Fiber Reinforced Polymer solution precisely designed by Dextra.
In unconsolidated excavation areas, like steel bolts, FRP Combination Bolt can be automatically installed by jumbo machine or manually installed.
Thanks to the characteristic of the FRP material, Combination Bolt can easily be cut by common excavation equipment, which makes the product an ideal solution for temporary application for tunnel excavation projects.

Product features

Corrosion free

Resistant to both acidic and alkali

Cuttable systems

Can be easily cut by common
excavation equipment.

Light weight

Easy handling, transportation and
installation inside the tunnel.

Related Projects

Deep Tunnel Sewerage System (DTSS) - Phase 2

Deep Tunnel Sewerage System (DTSS) – Phase 2

The Deep Tunnel Sewerage System (DTSS) is a used water infrastructure project being developed by the Public Utilities Board (PUB) of Singapore to meet the country’s long-term clean water needs.

Hyosung LPG Cavern

Hyosung LPG Cavern

Hyosung LPG Cavern includes LPG and petrochemical product production plants, storage tanks, and warehouses. For the construction of this project, Dextra GFRP rock-bolts were used.

Melbourne Metro: five new underground stations

Melbourne Metro

This Melbourne Metro extension features a 9 km long tunnel and five new underground stations. Dextra Griptec, Astec Combination Bolts, Astec Soil Nails and Soft-Eyes were selected for the construction of this project.

Related solutions

Soil Retention: Post-tensioned hybrid FRP+Steel cut-able ground anchor system used in excavation works.

Soil Stabilization:  Fully cut-able FRP soil nail system used for the stabilization of slope.

Soil Retention: Post-tensioned steel ground anchor system used in excavation works.


At every moment of your customer journey, Dextra teams dedicate themselves to the production of smart construction solutions that allow our customers to reach higher productivity and safety levels on their construction sites.

Dextra holds physical stocks on several continents, complemented in each country by the local inventories of our distributors. With this extended network, Dextra makes sure our products are always at reach no matter where our partners are.

For solutions that require to be customized, Dextra can also go beyond our standard delivery times and offer accelerated delivery schemes. Consult us for more information.

From 3 major industrial sites located in Bangkok (Thailand), Guangzhou (China), and Pune (India), Dextra completely owns its manufacturing facilities and processes. This allows us to have complete control over the timing of our operations and the quality of the solutions produced.

An independently accredited material testing laboratory, accredited to ISO-IEC17025, is located at Dextra’s main Bangkok factory, allowing the testing of material and products.

Dextra aims to supply products that exceed the most demanding international technical approvals and it is our goal to create maximum customer satisfaction by complying with our clients’ needs and specified requirements.

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