Frequently Asked Questions

What is the correct mix design for a site-batched non-shrink grout using Sika Intraplast Z for anchor bolt pocket grouting in a concrete foundation?

For a site-batched non-shrink anchor bolt pocket grout using Sika Intraplast Z, the recommended mix design is as follows. Materials per batch: 50 kg OPC (one standard bag), 50 to 100 kg clean washed fine river sand or M-sand (1:1 to 1:2 OPC:sand by weight depending on pocket size — use 1:1 for small precise pockets and 1:2 for larger void filling), water at 0.35 to 0.40 w/c ratio (17.5 to 20.0 litres per 50 kg OPC), Sika Intraplast Z at 0.4 per cent by weight of OPC (0.2 kg per 50 kg OPC bag — approximately one heaped 200 ml cup). Mixing procedure: pre-mix the dry OPC and sand until uniform. Dissolve the Sika Intraplast Z powder in a portion of the gauging water (approximately 2 to 3 litres). Add the Sika Intraplast Z solution and the remaining water to the dry mix and mix for at least 3 minutes in a mechanical paddle or drum mixer. Do not mix by hand — inadequate mixing prevents uniform distribution of the Sika Intraplast Z and results in uneven expansion. Consistency: the mixed grout should be fluid enough to pour and self-level in the anchor pocket without mechanical compaction — add the maximum water within the 0.35 to 0.40 w/c range for fluid consistency. Do not add excess water beyond 0.40 w/c ratio — excessive water addition negates the non-shrink expansion and produces a weak, porous grout that will shrink and crack.

What is the difference between Sika Intraplast Z and Sika Intraplast N and which should be specified for anchor bolt grouting vs post-tensioning duct grouting?

Sika Intraplast Z and Sika Intraplast N are both non-shrink and expansive grout admixtures from Sika but have different expansion mechanisms optimised for different grouting applications. Sika Intraplast Z uses a gas-generating expansion mechanism (chemical reaction producing controlled gas bubbles in the plastic grout) and is suitable for general-purpose anchor bolt pocket grouting, structural void filling, and column base plate grouting where volume control and non-shrink performance in the first few hours of hardening are the primary requirements. Sika Intraplast N (N for normal Portland cement compatibility) uses an expansive agent based on a different reaction optimised for cement grout in post-tensioning duct grouting, where the extremely fine grout (no aggregate, very high water:cement ratio of 0.44 to 0.50 for pumpability through fine ducts) requires a different expansion chemistry to prevent bleed-water separation and maintain duct fill without shrinkage voids. Post-tensioning duct grout specification is highly regulated by codes (IS 1343, fib Model Code) and typically requires certified pre-bagged duct grout products rather than site-batched mixes with admixtures — for post-tensioning duct grouting, consult Sika India for the appropriate pre-bagged grout product rather than specifying site-batched grout with Sika Intraplast. Specify Sika Intraplast Z for all standard general civil and structural anchor bolt, void filling, and base plate grouting applications where site batching is economical.

Can Sika Intraplast Z-modified grout achieve the same strength as SikaGrout 214-11 factory-bagged grout for machinery base plate grouting?

Site-batched OPC:sand grout with Sika Intraplast Z can achieve comparable compressive strength to SikaGrout 214-11 if the mix is correctly designed and quality-controlled — however, achieving the same strength in practice is more difficult due to the variability of site batching. SikaGrout 214-11 is factory-blended with controlled-quality OPC, graded fine aggregate, and expansion agent in a factory environment with consistent raw material quality, providing 55 to 65 MPa at 28 days reliably. A site-batched 1:1 OPC:fine sand grout with Sika Intraplast Z at w/c 0.35 can achieve 40 to 55 MPa at 28 days depending on the quality of the OPC, the cleanliness and grading of the sand, the mixing quality, and the accuracy of water batching on site. The principal risk with site batching is over-addition of water by the site gang to improve workability at the expense of strength — on a critical machinery grouting project where the grout strength is structurally specified, factory-bagged SikaGrout 214-11 eliminates the site batching variable entirely. On less critical grouting (large volume structural voids, road kerb joints, non-critical anchor bolt pockets), Sika Intraplast Z site-batched grout is a cost-effective and technically adequate alternative. For machinery base plate and critical structural column base plate grouting, specify SikaGrout 214-11. Contact Space Arc Engineering for both products and technical advice on the appropriate choice for your specific application.