Citi-Con has extensive experience grouting industrial equipment to ensure its stability, longevity and performance.
It is important to note that rotating equipment and heavy machinery cannot be mounted directly on a concrete foundation. This is considering that slab and machine base irregularities will result in load-bearing issues and alignment difficulties. Furthermore, a concrete foundation is not strong enough to withstand the compressive and dynamic loading of heavy machinery. Therefore, machinery bases are aligned and levelled by shims or jack bolts above the concrete foundation. The space between the machine and the concrete base needs to be filled with grout.
This means that the grout must be fluid enough to be placed under the baseplate to fill this space. It must also maintain its volume throughout the service life of the equipment to ensure intimate contact between the surfaces. This ensures maximum load-bearing capability.
Our quality equipment grouting
Our quality equipment grouting safeguards against premature machinery failure. This is by ensuring that vibrations travel seamlessly from equipment to the foundation mass where they dissipate. If the equipment is misaligned due to poor grouting, vibrations compound until equipment components, such as bearings, are damaged.
Furthermore, the correct grout must be used. Poor quality grout and grouting workmanship will not be able to withstand constant dynamic loads. A quality grout will ensure a positive bond on both the equipment base and the concrete foundation to form a monolithic structure. This safeguards your investment.
Hairline cracks in the shoulder of the grout is one of the most common problems. It can cause water ingress if the foundation is outdoors and exposed to severe weather. Thermal expansion of the base plate can occur when it is welded, resulting in spalling or cracking of the grout. Grout shrinkage can cause gaps between the machine and the grout, resulting in vibration that exceeds safe operating levels.
Correct grout for equipment grouting
Therefore, Citi-Con will always ensure that it selects the correct grout for equipment grouting as a fundamental first step.
This is based on an array of factors. These include vibration levels, load-bearing requirement and exposure to chemicals.
A free-flowing, high strength or synthetic resin-based mortar is used for a myriad of applications. These include filling voids under machines and structural elements, as well as securing anchors. SikaGrout®-212 | Low Shrinkage General Purpose Grout and SikaGrout®-295 ZA | Cementitious Grouting to Fill Voids are examples. SikaGrout®-3200 ZA | Cementitious Grouting to Fill Voids can even be used on wind turbine foundations.
Epoxy grouts are ideal for high-impact loads, dynamic machinery and aggressive environments. This is by providing high creep and chemical resistance and strong adhesion to steel. A case in point is E3-Deep Pour, formulated to be used in deep placements for maximum bearing capacity for numerous base configurations. Refer to E3-Deep Pour – Euclid Chemical.
Grout type will also influence the surface preparation method that needs to be done to ensure a strong bond. This may entail roughening the surface using bushing, chipping or sandblasting techniques.
When using cementitious grouts, we always ensure that there is no oil, grease and dust traces on concrete and steel surfaces. Thereafter, we roughen the concrete surface to expose course aggregate. Then we presoak the concrete with water for between eight and 24 hours, before removing standing water.
When using epoxy grouts, we ensure that the surfaces are dry. Any contaminants are removed and the concrete roughened, and steel surfaces prepared to an SSPC-SP6 commercial finish. Refer to Surface Prep Standards – A Quick Summary.
Equipment grouting and quality grouts
Citi-Con’s equipment grouting team is an approved applicator of quality grouts.
All grout manufacturers publish properties of their products, the outcome of independent and inhouse testing. However, these properties are not uniformly reported for various reasons.
The grouts that we use for equipment grouting must demonstrate the following properties:
- Compressive strength
- Creep resistance
- Modulus of elasticity
- Fatigue resistance
- Impact resistance
- Coefficient of thermal expansion
- Flowability and bearing area
A combination of compressive strength (Cementitious-materials-for-concrete-standards-selection-and-properties-2024-2.pdf), flowability and bearing area are especially important for overall long-term performance. For grout to be able to withstand repeated loading, it needs to be fatigue and impact resistant.
Getting equipment grouting right
Getting equipment grouting right also relies on well-sealed forms which contain the grout and maintain the correct pour shape.
Citi-Con uses materials that can withstand the weight and pressure of the grout while preventing leaks or blowouts during placement. We also ensure that there is a 2,54cm to 5,08cm clearance around the baseplates for flow.
When using cementitious grouts, we apply form release agents on areas where bond is not desired. A coat with multiple layers of paste wax is deployed for epoxy grouts.
Citi-Con also uses a suitable mixing method to ensure grout consistency. Cementitious grouts require aggressive, high-energy mixing to activate the cement and achieve proper flow. We use a mortar mixer to achieve the best results, although a drill-and-paddle type is suited to mixing small batches. Mixing usually takes four to five minutes until the mortar is smooth and lump-free.
Epoxy grouts are mixed at low speeds to avoid air entrapment and excessive heat buildup, compromising strength and work time. Between 6,6l and an 10l of water is mixed with a 45kg bag of grout.
Ahead of mixing, we pre-condition all components to between 21,10C and 26,6oC for optimal performance. Thereafter, we first mix the resin and hardener until fully blended and then add aggregate slowly. This while mixing in a mortar mixer. We use four bags of aggregate for high flow applications and five bags for standard flow. To avoid air entrapment, we avoid excessive mixing.
Curing equipment grouting
Curing is a critical step in our equipment grouting process. Therefore, it must be done correctly and never rushed.
Cementitious grouts are wet cured for at least three days using a damp burlap or plastic sheets. An appropriate curing compound is added after 24 hours to retain moisture and prevent cracking.
Epoxy grouts must be protected from water and direct sunlight during curing to prevent soft spots or incorrect chemical reactions. Cure time depends on temperature, but we generally plan for between 24 and 48 hours.
Learn more about Citi-Con and our capabilities. www.citicon.co.za