Frequently Asked Questions

What is the minimum embedment depth for a 16 mm diameter threaded rod anchored with Sika AnchorFix 3001 in C25 concrete for a design tensile load of 30 kN?

Anchor design using Sika AnchorFix 3001 must be performed using the Sika AnchorFix design software or the ETA-approved design method (ETAG 001 Annex C or EN 1992-4) applied to the product ETA values — anchor design cannot be reliably performed from general rules of thumb. As a general indicative reference only (structural engineer must verify): for a single 16 mm diameter threaded rod (M16) in C25 concrete (25 MPa characteristic compressive strength) with no edge or spacing effects and loaded in tension only, the characteristic bond resistance per unit embedment depth for Sika AnchorFix 3001 in uncracked concrete is approximately 12 to 15 MPa (varying with hole drilling method — rotary drill vs hammer drill). For a target design tensile load of 30 kN, with an appropriate partial safety factor of 1.5 to 2.0 (depending on failure mode, load category, and design code), the required characteristic tensile resistance is 30 x 2.0 = 60 kN. At a bond resistance of 12 MPa, the required embedment length is: 60,000 N / (pi x 16 mm x 12 N/mm2) = 60,000 / 603.2 = approximately 100 mm. With partial safety factor already applied, the design embedment is approximately 10 x bar diameter (160 mm) to 12 x bar diameter (192 mm) for M16 in C25 concrete — typical Indian design practice uses 10 to 15 bar diameters as a rule of thumb for preliminary estimates. All final embedment depths for structural connections must be calculated by a qualified structural engineer using the ETA documentation for Sika AnchorFix 3001 and the applicable Indian or international design code.

How should Sika AnchorFix 3001 holes be cleaned before injection and what happens if the drill dust is not removed?

Hole cleaning before Sika AnchorFix 3001 injection is as critical for adhesive anchor strength as it is for Sikadur 31 CF Normal — drill dust and concrete slurry in the hole wall are the most common cause of adhesive anchor pull-out failures. The drill dust creates a weak interlayer between the adhesive and the concrete, reducing the effective bond area and allowing the anchor to fail at a fraction of its design load. The correct cleaning sequence (per Sika AnchorFix and ETA requirement): Step 1 — Blow out: insert a compressed air nozzle or hand bellows pump to the bottom of the hole and blow out all dust from bottom to top using compressed air at minimum 4 bar pressure. Repeat 4 times. Step 2 — Brush: insert a nylon cleaning brush of the appropriate diameter (matching the hole diameter) to the full depth of the hole and brush vigorously 4 full rotations pulling back while rotating. Step 3 — Blow again: repeat the compressed air blowing after brushing to remove the debris loosened by the brush. Repeat this blow-brush-blow sequence a minimum of 4 times (or until the air exiting the hole is visually clean). Step 4 — Final inspection: inspect the hole with a torch — the walls should appear clean, grey concrete without dust coating. Dry holes give the best bond strength — if the hole has water ingress, inform the engineer as Sika AnchorFix 3001 has limited suitability for wet or flooded holes (Sika AnchorFix 3+ or water-tolerant grades are specified for wet conditions).

Can Sika AnchorFix 3001 be used in hollow brick masonry or AAC block walls for anchoring shelving brackets and what are the limitations?

Sika AnchorFix 3001 can be used in hollow brick masonry and solid masonry (no hollow voids) for limited loads — but it is NOT suitable for anchoring in hollow core or lightweight AAC (autoclaved aerated concrete) blocks without using a sleeve or screen tube anchor system. In hollow brick masonry with void cavities: injecting Sika AnchorFix 3001 directly into a hollow-void drill hole will result in the adhesive flowing into the void instead of filling the annular gap around the anchor rod — the anchor will have adhesive contact only at the face shell of the brick, with no bond along the void section of the embedment, severely reducing pull-out capacity. For hollow masonry anchoring with Sika AnchorFix 3001, a perforated metal sleeve or fibre mesh screen tube is inserted into the hole first; the adhesive is injected through the tube to fill the cavity behind the face shell; then the anchor rod is inserted. This screen-tube injection method traps the adhesive around the rod in the void area and substantially increases pull-out capacity. For AAC blocks (Autoclaved Aerated Concrete — very low density, 400 to 650 kg per m3): the base material strength of AAC is very low (typically 2 to 4 MPa compressive strength), and any anchor system including adhesive anchors has very limited pull-out capacity in AAC. For light shelf brackets in AAC block walls (loads below 0.5 to 1.0 kN per anchor), Sika AnchorFix 3001 with screen tube may be adequate. For heavier loads in AAC walls, consult Space Arc Engineering for appropriate anchor system alternatives.