Equipment grouting: work sequence and quality control

Why equipment is grouted

The unit is levelled and aligned on wedges, jacking screws or shims, after which the gap between the baseframe and the foundation is filled with grout. If everything is done correctly, the baseframe bears on the grout over its entire area, vibration is damped by the mass of the foundation, the anchors work as intended in the design, and the alignment holds for years. Voids under the baseframe, grout debonding and cracks are a common cause of excessive vibration and premature wear of bearings and seals.

The general work sequence is set out below. Specific values (substrate pre-soaking time, permissible temperatures, pour depth, time before anchor tightening) are always taken from the technical data sheet of the selected material and the installation documentation for the unit.

1. Choosing the material

static or moderately loaded equipment, large volumes — non-shrink flowable cementitious grout;
reciprocating machinery, high-speed turbomachinery, impact loads, chemically aggressive environments, short time to start-up — epoxy grout;
the gap height and flow distance must be within the limits specified by the manufacturer.

For more detail, see the “Cementitious grouts” and “Epoxy grouts” sections.

2. Foundation preparation

The foundation concrete must have reached its design strength; manufacturers of epoxy systems usually specify a minimum concrete age.
The weak top layer and laitance are removed with a chipping hammer down to sound concrete with exposed aggregate. Grinding is unsuitable for this — it “polishes” the surface.
The surface is cleaned of dust and oil. Oil stains that have soaked into the concrete are cut out.
Anchor pockets and sleeves are cleared of debris, water and ice.
For cementitious grout, the substrate is pre-soaked and standing water is removed before pouring. For epoxy grout, by contrast, the substrate is kept dry unless the technical data sheet permits a damp one.

3. Equipment preparation

The contact surfaces of the baseframe are cleaned of paint, rust and oil. Epoxy grouts usually require abrasive blast cleaning; some manufacturers accept a factory-applied primer compatible with epoxy.
Levelling screws and wedges that will be removed after the grout has hardened are greased or wrapped so that the grout does not bond to them.
Anchor bolts are wrapped or sleeved over the length where they must be free to stretch when tensioned — this way the bolt works over its full design length.
The baseframe is checked for vent holes to let air escape; if necessary, they are drilled.

4. Formwork

Formwork must be rigid and grout-tight: joints and the junction with the concrete are sealed with sealant or polyethylene foam backing rod.
On the pouring side, the formwork is set back from the baseplate and raised above its underside to create a head of grout. An inclined chute or a head box is convenient.
On the opposite side, a small gap is left for air to escape and to check that the grout has flowed through.
For epoxy grouts, the formwork is coated with wax, polythene or a release agent.
For long baseframes, expansion joints in the grout are designed as recommended by the manufacturer.

5. Temperature conditions

Before pouring, measure the temperature of the air, the concrete, the baseframe steel and the material itself. In Tashkent, Samarkand and Navoi, steel in the summer sun can get hotter than the maximum permitted for application — in that case a canopy is put up, work is done in the cooler part of the day and the materials are cooled. In winter, a heated enclosure is set up if necessary. For epoxy systems, the dew point must be taken into account: condensation on a cold baseframe impairs adhesion.

6. Mixing and pouring

The volume is calculated in advance and material is prepared with a margin, so that the pour can proceed without interruption.
Cementitious grout is mixed with an accurately measured quantity of water in a mixer for the specified time. Epoxy components are mixed in full kits, with the filler added gradually.
The grout is poured from one side (or from one side and the adjacent end), maintaining a constant head, until it emerges on the opposite side and through the vent holes.
Grout is not normally vibrated; to help it along, straps or cables are worked back and forth under the baseplate, if the manufacturer permits this.
Do not pour from several sides at once, do not interrupt the pour, and do not add water to grout that has started to set.

7. Curing and start-up

Cementitious grout is immediately covered with wet hessian or polythene sheeting and kept moist; this is particularly important in windy and hot weather.
Epoxy grout is protected from water and temperature fluctuations until it has cured.
Levelling screws are backed off or removed once the grout has reached the required strength, and the holes they leave are filled.
Anchors are tightened and the unit is started up no earlier than the time stated in the technical data sheet for the actual temperature.

8. Quality control

Taking specimens from each batch for compressive strength testing.
Tap testing the baseframe after hardening to locate voids. Any voids found are filled by injecting a low-viscosity resin.
Checking alignment after the anchors have been tightened and during the first weeks of operation.
Keeping a log: batches, temperatures, start and finish times of the pour.

Materials from leading manufacturers

SikaGrout-214, SikaGrout-314 — Sika — non-shrink cementitious grouts for turbines, compressors, pumps and baseplates.
Sikadur-42 MP Normal — Sika — epoxy grout for machinery and baseplates; the technical data sheet refers to API creep requirements.
Mapefill — Mapei — fluid cementitious grout for machine tool beds and steel structures.
Planigrout 300, Planigrout 310, Planigrout 350 — Mapei — epoxy grouts for presses, compressors and heavy machinery.
Chockfast Orange, Chockfast Black — ITW Performance Polymers — chocking of engines, compressors and generators, including hot machinery.
Chockfast Red, Chockfast Red SG — ITW Performance Polymers — full epoxy grouting under large machinery and baseframes.
Conbextra HF — Fosroc — high-flow cementitious grout for precision work.
Conbextra EP65 Plus — Fosroc — fast-curing epoxy grout for machinery and turbines.
MasterFlow 928 — Master Builders Solutions (now SikaGrout-928) — cementitious grout with extended working time.
MasterFlow 648 — Master Builders Solutions (now SikaFlow-648) — epoxy grout for dynamic loads.
Five Star Fluid Grout 100 — Five Star Products — fluid sulphate-resistant cementitious grout.
Five Star HP Epoxy Grout — Five Star Products — epoxy grout for rotating equipment.
PAGEL V1/10, V1/50 — Pagel Spezial-Beton — pourable cementitious grouts for precision machine tools, turbines and generators.
Five Star Metallic Grout — Five Star Products — metallic-aggregate cementitious grout for machinery under impact and vibration.
Five Star High Strength Grout — Five Star Products — high-strength cementitious grout for machinery and turbo equipment, 89.6 MPa.
Five Star HTR Grout — Five Star Products — cementitious grout for equipment operating at up to 1316 °C.
Five Star Epoxy Chock / Epoxy Chock EX — Five Star Products — epoxy chocking compound for compressors, turbines and other aligned machinery.
Euclid E3-Deep Pour — Euclid Chemical — deep-pour epoxy grout for equipment bases, lifts up to 46 cm.
PAGEL V15 (V15/50, V15/50SF) — Pagel — basalt-aggregate grout for heavily vibrating machinery and crane rails.
Euclid NS Grout — Euclid Chemical — non-shrink non-metallic cementitious grout for machinery, pumps and anchor bolts.
Euclid Tammsgrout Supreme — Euclid Chemical — high-strength non-shrink cementitious grout for heavy machinery and crane rails.
Euclid Hi-Flow Metallic Grout — Euclid Chemical — high-flow metallic-aggregate cementitious grout for heavy machinery and crane rails.
Mapefill F — Mapei — sulphate-resistant fluid cementitious grout for precision anchoring of machine tools and steel structures.
Mapefill MF 610 — Mapei — fibre-reinforced expansive grout for precision anchoring of equipment in layers over 5 cm.
Mapefill HS — Mapei — super-flow high-strength non-shrink grout for precision anchoring of equipment.
Planigrout 728 — Mapei — non-shrink precision cementitious grout for base plates and anchor bolts.
SikaGrout-713 — Sika — non-shrink mineral-aggregate grout for precision equipment grouting.
SikaGrout-885 MF — Sika — low-dust metallic-aggregate grout for heavy and dynamically loaded machinery.
Fosroc Conbextra HR — Fosroc — heat-resistant non-shrink grout for blast furnaces and hot equipment.
Mapefill GP Plus — Mapei — fluid non-shrink grout for precision anchoring of machinery and steel structures.
SikaGrout-350 — Sika — non-shrink cementitious grout for deep pours up to 300 mm under equipment.
SikaGrout-295 US — Sika — high-strength fluid expanding cementitious grout for baseplates and machinery.
SikaFlow-649 — Sika — high-strength high-temperature epoxy grout for machinery, rails and wind turbines.
SikaFlow-668 — Sika — epoxy chock grout for mounting compressors, turbines and machinery.
Fosroc Conbextra GP4 — Fosroc — high-strength non-shrink precision grout for turbines, compressors and pumps.
Fosroc Conbextra GP5 — Fosroc — ultra-high-strength non-shrink cementitious grout for heavy-duty equipment.
Fosroc Conbextra HT — Fosroc — rapid-strength heat-resistant cementitious grout up to 400 °C for hot works.
Fosroc Conbextra EP160 — Fosroc — solvent-free epoxy grout for deep gaps up to 200 mm.
Fosroc Conbextra 621 — Fosroc — dual-expansion non-shrink precision grout for turbines, presses and rails.
Fosroc Conbextra GP2(N) — Fosroc — free-flow non-shrink grout for turbines, compressors and anchor bolts.
Fosroc Conbextra GV — Fosroc — low-exotherm self-levelling grout for 70–150 mm gaps under machine beds.
Fosroc Conbextra EBG(M) — Fosroc — thixotropic epoxy bearing grout for 3–50 mm gaps under equipment.
SikaGrout-114 — Sika — dual-expansion non-shrink grout for machine foundations and baseplates.
SikaGrout-275 — Sika — high-strength non-shrink precision grout for machinery, layers up to 100 mm.
SikaGrout-950 — Sika — high-strength non-shrink grout for turbines, presses and crane rails.
SikaFlow-400 — Sika — free-flowing epoxy grout for machinery, anchors and crane tracks, 20–80 mm.
Skrepa Samonivelir — Penetron — flowable B50 mortar for horizontal repairs and grouting under columns and equipment.
Mapefill 10 — Mapei — non-shrink flowable concrete grout with 10 mm aggregate for grouting under machinery.

Frequently asked questions

Can wedges and jacking screws be left in the grout?

That is decided by the installation documentation for the unit. Often the screws are backed off or removed after the grout has hardened, so that the baseframe bears on the grout rather than on point supports; for this reason they are greased or wrapped beforehand. Steel wedges left in place create hard support points, so whether they are to be removed or left in is agreed in advance.

How soon can the anchors be tightened and the equipment started up?

The time depends on the material and the actual temperature and is taken from the technical data sheet. For example, Five Star requires HP Epoxy Grout to reach the necessary strength and modulus of elasticity before the anchors are tightened; in cold weather the waiting times increase considerably.

How can you check that there are no voids under the baseframe?

Once the grout has hardened, the baseframe is tapped with a hammer: a hollow sound indicates a void. Voids are filled by injecting low-viscosity resin through drilled holes, working from one edge to the other.

Is grout needed if the equipment sits on shims?

As a rule, yes: grout distributes the load, damps vibration and protects the anchors. The exception is chocked installations, where the unit is deliberately supported on individual polymer chocks.