Most requested grouts
- SikaFlow-648 (MasterFlow 648) — Sika — epoxy grout for equipment under vibration, 10–150 mm.
- Chockfast Red — ITW — epoxy grout for large machinery and baseplates.
- SikaGrout-928 (MasterFlow 928) — Sika — non-shrink flowable cementitious grout, 20–200 mm.
- SikaGrout-980 (MasterFlow 980) — Sika — cementitious micro-concrete for deep pours, aggregate up to 8 mm.
What is grout?
Grout (referred to in Russian-language documentation as podlivka or grunt-rastvor) is a flowable or plastic mix used to fill the gap between a foundation and the element it supports: a pump baseframe, a compressor baseplate, a column base, a crane rail or the flange of a wind turbine tower. The purpose of grouting is not simply to “fill the gap” but to make the steelwork and the concrete act as a single support, so that the load is transferred evenly over the whole bearing area rather than through individual shims and anchor bolts.
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Grout differs from ordinary mortar in three respects. First, it compensates for shrinkage: once hardened, it does not pull away from the baseplate — otherwise a void is left underneath and the whole exercise is wasted. Second, it flows the required distance through a narrow gap without segregation and without vibration. Third, it gains strength quickly, so that the equipment can be put into service on a tight schedule.
Where grouts are used
- installation of pumps, compressors, generators, turbines, gearboxes, crushers, mills, presses and machine tools;
- grouting under the baseplates of steel columns and under precast concrete elements;
- grouting in anchor bolts and cast-in items, anchoring of starter bars;
- grouting under crane rails and crane girders, including the runways of port and workshop cranes;
- bridge bearings and joints in precast structures;
- wind turbine foundations (the tower-to-foundation connection);
- marine and offshore equipment (so-called chocking — mounting on polymer “chocks” instead of steel shims).
Two main classes: cementitious and epoxy
| Criterion | Non-shrink cementitious grout | Epoxy grout |
|---|---|---|
| Composition | Portland cement, graded aggregate, expansive and plasticising admixtures | two- or three-component system: resin, hardener, mineral filler |
| Mixing | with water on site | by combining the factory-proportioned components, without water |
| Typical applications | static and moderate loads, columns, anchor bolts, large volumes | vibration, impact and cyclic loads, precision machinery, aggressive environments |
| Layer thickness | from thin gaps to mass pours (special grades can be extended with crushed stone) | limited by the heat of reaction; large volumes are placed in pour sections or with special grades |
| Chemical resistance | that of hardened cement paste — vulnerable to acids, sulphates and oils | high resistance to oils, many acids, alkalis and salts (according to the manufacturer’s tables) |
| Adhesion to steel and concrete | mechanical bond; substrate preparation required | high adhesive strength |
| Cost | lower | significantly higher |
There are also intermediate solutions: polymer-modified cementitious grouts and rapid-hardening grouts based on special binders, for repairs completed “within a shift”. For anchoring, injection anchor resins (epoxy, vinyl ester) are used as well as grouts; they are dispensed from a cartridge into a drilled hole.
How to choose a grout
1. Type of loading
For a building frame column or a vessel, where the load is mainly static, a non-shrink cementitious grout of the appropriate strength class is usually sufficient. Where the support is subject to vibration, impact or alternating loads — reciprocating compressors, gas engine-driven compressors, diesel generators, crushers — designers generally switch to epoxy grouts: they cope better with dynamic loading and do not break down under vibration at the interface with the baseplate.
2. Gap height and volume
Every material has a minimum and a maximum layer thickness stated in its technical data sheet. If the gap is too thin, a cementitious grout will not flow through it; if an epoxy grout layer is too thick, it will overheat and crack. Where the gap is large, choose a grade that allows deeper pours, or extend the cementitious grout with crushed stone as recommended by the manufacturer.
3. Flow distance
Under a wide baseplate, the material has to travel from one side to the other, displacing the air. Flowability, the use of a head box and the working life all matter here. For long flow paths, choose flowable grouts with high fluidity.
4. Temperature during placing and in service
In summer in Uzbekistan, the substrate and steelwork in direct sun get much hotter than the air, which shortens the working time of the material, especially with epoxy systems. In winter, cementitious grout gains strength slowly and may freeze. The technical data sheet of every material gives the permissible application temperature range; for hot equipment (turbine casings, compressors), the maximum service temperature of the grout is checked separately.
5. Chemical exposure
Oils, fuel, electrolytes and the acids found in chemical and food-processing plants attack hardened cement paste. In such areas, epoxy grouts are used, and resistance to the specific medium is confirmed by the questionnaire.
6. Time to start-up
If the equipment has to be running the next day, choose a grout with high early strength and check in the technical data sheet what strength it will have reached by then at the actual temperature.
7. Design requirements and standards
Designs often refer to ASTM C1107 (non-shrink cementitious grouts), ACI 351.1R (grouting under equipment), API RP 686 (machinery installation), and EN 1504-3 and EN 1504-6 (repair mortars and anchoring of reinforcing steel). When selecting a substitute for the grade specified in the design, compare not only the strength but also the test method, the age of the specimens and the temperature at which the figures were obtained.
Sections of the reference guide
- Cementitious grouts — non-shrink and expansive grouts, flowable and thixotropic, common placing mistakes.
- Epoxy grouts — when epoxy is needed, exotherm, thickness and temperature limits.
- Equipment grouting — the work sequence from substrate preparation to start-up.
- Anchoring and anchor grouting — grouting in bolts, anchor resins.
- Crane rails — grouting under crane rails and crane girders.
- Wind turbine grouts — foundations and tower flanges: fatigue and dynamic loads, thick pours, work in heat and frost.
Materials from leading manufacturers
A selection of the main product ranges. Check the properties of a particular grade in its own technical data sheet: the content of Sika and Mapei data sheets varies with the country of issue.
Cementitious grouts
- SikaGrout-212, SikaGrout-214, SikaGrout-314, SikaGrout-318 — Sika — non-shrink flowable grouts for machinery, baseplates and anchors.
- Mapefill, Mapefill R, Mapefill GP — Mapei — expansive fluid mortars for grouting and anchoring.
- Conbextra GP, Conbextra HF, Conbextra HS — Fosroc — general-purpose non-shrink grouts and high-strength precision grouts.
- MasterFlow 928, MasterFlow 4316 — Master Builders Solutions (now Sika) — a non-shrink grout with extended working time and an ultra-high-strength grout for machinery and wind turbines.
- Five Star Grout, Five Star Fluid Grout 100 — Five Star Products — non-shrink grouts to ASTM C1107.
- PAGEL V1/10, V1/50, V1/50HF — Pagel Spezial-Beton — pourable grouts in different aggregate sizes, including grades for wind turbines.
Epoxy grouts
- Sikadur-42 (MP Normal, HE and regional versions) — Sika — grout for machinery, baseplates and crane rails.
- Chockfast Orange, Chockfast Black, Chockfast Gray, Chockfast Red, Chockfast Red SG — ITW Performance Polymers — chocking compounds and grouts for machinery.
- Planigrout 300, Planigrout 310, Planigrout 350 — Mapei — epoxy grouts for heavy machinery and rails, covering different layer thicknesses.
- Conbextra EP10, EP65 Plus, EP120 Plus — Fosroc — epoxy grouts for thin, medium and large gaps.
- MasterFlow 648 — Master Builders Solutions (now SikaFlow-648) — a three-component precision epoxy grout.
- Five Star HP, DP, Rapid Epoxy Grout — Five Star Products — epoxy grouts for dynamically loaded equipment.
- PAGEL EH196R, EH196S — Pagel — epoxy grouts for rails and precision supports.
Frequently asked questions
Can grout be replaced with ordinary sand-cement mortar?
No. Ordinary mortar shrinks and pulls away from the baseplate, flows poorly through a narrow gap and segregates when water is added. As a result, voids are left under the baseframe and the load is transmitted through isolated points.
When should epoxy grout be chosen instead of cementitious grout?
When the equipment generates vibration, impact or cyclic loads; when oils and chemicals are present in the area; when the unit has to be put into service quickly; or when the design and the equipment manufacturer’s installation documentation require it.
Can grades be compared on the strength values in their technical data sheets?
Only under identical conditions: test method, specimen size, age, temperature and consistency. Figures obtained to ASTM and to EN, or on cubes and on prisms, are not directly comparable.
What grout thickness is permissible?
Each material has its own range, stated by the manufacturer. For epoxy grouts, the maximum thickness per pour is limited by heat generation; for cementitious grouts, by bleeding and heat build-up. For large gaps, special grades are chosen or the grout is placed in layers.
Does a hot climate affect the choice of grout?
Yes. High temperatures shorten the working time of the material and intensify the exotherm of epoxy grouts. Check the upper application temperature limit in the technical data sheet and schedule the pour for the cooler part of the day.