Sika Rokkon-1
Water-activated, chloride-free cementitious capsule for fast, non-shrink rock-bolt anchoring in tunnelling and underground mining.
What is it?
A pre-packed cementitious capsule (sausage form in a perforated pouch) that turns into a non-shrink, thixotropic grout once soaked in water, used to bond rock bolts into their boreholes.
Where is it used?
Underground works where strata need reinforcing: road and rail tunnels, metro and hydroelectric headworks, mine roadways, slope faces and portal cuttings.
Why use it?
It gives a clean, corrosion-safe, laboratory-consistent alternative to on-site mixed grout, developing early strength so bolts can carry load quickly without chloride attack on the steel.
How is it applied?
Soak the capsule in water for a few minutes, push it up the borehole ahead of the bolt, then spin or drive the bolt through to burst the pouch and distribute the grout around the anchor.
About Sika Rokkon-1
Sika Rokkon-1 is a factory-produced cementitious grouting capsule made specifically for anchoring rock and roof bolts in tunnels and underground mines. Instead of batching grout at the face, the crew works with a sealed sausage-shaped capsule held inside a perforated plastic pouch. The dry cementitious blend, the additives and the water-to-cement ratio are all fixed in the factory, so every capsule that reaches the borehole behaves the same way. For a distributor-supplied product feeding demanding infrastructure jobs, that repeatability is the whole point: it removes the guesswork of hand-mixing in a wet, dusty, low-light environment where a bad batch is hard to spot and harder to fix once a bolt is in.
The capsule is designed around a simple installation sequence. It is dipped in water for a short soak so the liquid percolates through the perforations and wets the cement, then it is placed up the hole and the bolt is inserted through it. As the bolt advances it splits the pouch and drives the now-plastic grout into the annulus between steel and rock. The mix is chloride-free, which matters because the whole assembly is a steel bolt sitting permanently in a damp ground mass — any chloride would invite corrosion at exactly the point where the anchor must stay sound for the life of the structure. Space Arc supplies Rokkon-1 across Delhi NCR and pan-India for tunnelling contractors, mining operators and geotechnical specialists who need a consistent, corrosion-safe cementitious anchor system.
The technical insight
The clever part is how the capsule controls water. A rock-bolt grout has two competing needs: it must take up enough water to hydrate the cement, but not so much that the mix becomes soupy and runs out of an overhead or steeply inclined hole. Rokkon-1 handles this through the perforated pouch and a set of formulation additives that meter water uptake toward an optimum water-to-cement ratio while keeping the grout thixotropic — stiff at rest, briefly workable when sheared by the spinning bolt, then stiff again. That thixotropy is what lets it stay put in up-holes rather than draining back down the annulus. On top of this, controlled non-shrink expansion counteracts the natural shrinkage of hydrating cement, so the grout keeps positive contact against both the bolt and the borehole wall instead of pulling away and leaving a debonded gap. The chloride-free chemistry lets it build early strength without the corrosion penalty that chloride-accelerated systems carry, which is why it is considered safe against embedded steel over the long term.
Where it is used
- Grouting rock and roof bolts for strata reinforcement in road and rail tunnels
- Anchoring bolts in underground mine roadways and development headings to control roof falls
- Bolt fixing in hydroelectric headrace tunnels, surge shafts and powerhouse caverns
- Support bolting in metro and utility tunnels driven through rock
- Slope and cut-face stabilisation with pattern-bolted anchors
- Portal, adit and shaft-collar reinforcement at tunnel entries
- Ground anchoring in geotechnical works where a cement-based, corrosion-safe system is specified
- Rib and sidewall support where overhead and inclined holes need a non-draining grout
Key advantages
- Factory pre-packed for consistent, laboratory-tested grout quality on every capsule
- Chloride-free chemistry protects the embedded steel bolt against corrosion
- Controlled non-shrink expansion keeps positive contact between bolt, grout and rock
- Thixotropic consistency resists grout loss in overhead and steeply inclined holes
- Simple water-soak activation removes on-site batching, mixing plant and spillage
- Rapid strength gain lets bolts take load and tunnelling progress continue sooner
- Clean, low-waste system suited to confined, poorly lit underground working faces
- Available in multiple capsule diameters to suit common borehole and bolt sizes
Limitations & considerations
- A cementitious system develops full strength more slowly than resin capsules, so it is not the fastest option where near-instant load-up is essential
- Correct soak time is critical — under-soaking starves the cement of water while over-soaking dilutes the mix and weakens it
- Capsule diameter must be matched to borehole and bolt diameter; a poor annulus fit compromises encapsulation
- Sensitive to storage — capsules must stay dry and sealed in the original packaging or they hydrate prematurely
- Setting behaviour and strength gain shift with ground and water temperature, so cold or very hot conditions need trial verification
- Not intended as a general structural repair or free-flowing machine-base grout; it is a dedicated rock-bolt anchoring capsule
Selection & best practice
Match the capsule diameter to the borehole so the annular gap around the bolt is neither too tight to insert nor too wide to fill, and verify the pairing against the bolt and hole sizes before the shift starts. Keep boxes dry and sealed until the moment of use, and take only what the face needs. Soak each capsule in clean water for the specified few minutes — time it rather than eyeballing it, because both under- and over-soaking degrade the anchor. Push the wetted capsule to the back of a clean, flushed hole, then insert and spin the bolt fully through to burst the pouch and shear the grout so it packs the full annulus. In cold or hot ground, run a small trial to confirm set and early strength before committing to production bolting. Where holes are wet or heavily fractured, review the installation approach with the technical team, and always follow the current Sika product data sheet and safety data sheet for site-specific soak times, capsule counts and handling.
Specifications
| Product type | Cementitious capsule for rock-bolt grouting (sausage form in perforated pouch) |
| Base | Special chloride-free cement blend with controlled-expansion additives |
| Activation | Water soak for approx. 3-4 minutes at +30 C |
| Initial setting time | 3-8 minutes at +30 C |
| Final setting time | 10-20 minutes at +30 C |
| Compressive strength (1 day) | >= 11 N/mm2 |
| Compressive strength (7 days) | >= 18 N/mm2 |
| Compressive strength (28 days) | >= 27 N/mm2 |
| Capsule sizes / pack | 25 mm x 300 mm (100/box), 32 mm x 300 mm (75/box), 40 mm x 300 mm (12/box) |
Industry use cases
Tunnelling (transport)
Pattern rock-bolting of crown and sidewalls in road, rail and metro tunnels driven through competent to fractured rock, using a corrosion-safe cementitious anchor.
Underground mining
Strata reinforcement in mine roadways and development headings to reduce roof-fall risk, with capsules that install quickly at the face without batching plant.
Hydropower
Bolt anchoring in headrace tunnels, surge shafts and powerhouse caverns where permanently damp ground demands a chloride-free, non-shrink grout.
Geotechnical / slope works
Pattern-bolted stabilisation of rock cuttings, portals and slope faces where a consistent pre-packed grout suits difficult, exposed working positions.
Frequently asked questions
How do you install a Sika Rokkon-1 capsule?
Why is a chloride-free grout important for rock bolting?
How many capsules do I need per bolt?
What makes it hold in overhead and inclined holes?
How is Rokkon-1 different from a resin anchor capsule?
How should the capsules be stored on site?
How we position Sika Rokkon-1
Sika Rokkon-1 sits in our grouts and anchors range as the go-to cementitious, chloride-free capsule for rock-bolt anchoring in tunnels and mines. Within the Sika family it pairs naturally with the wider Rokkon rock-bolting line (such as the Rokkon R fast-setting variants for jobs needing quicker strength) and with Sika’s SikaGrout cementitious grouts for base plates and machine bases where a flowable, high-strength grout is called for rather than a bolt capsule. Where a project instead needs a resin anchor that loads up almost instantly, or a chemical anchor for bolts and rebar into concrete and masonry, we would point specifiers to a filled polyester resin system. Talk to our team about matching capsule diameters to your borehole and bolt sizes across Delhi NCR and pan-India.
Fosroc Lokfix — A specifier who needs an anchor that takes load almost immediately, or is fixing bolts and rebar into concrete or masonry rather than pattern-bolting rock, may prefer this fast-setting filled polyester resin over a cementitious capsule.
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