Frequently Asked Questions

What is the correct procedure for grouting a heavy industrial machine base plate using MC-Grout 300 in fluid consistency, and how should the grout be mixed and placed to achieve a void-free result?

Grouting a heavy industrial machine base plate is a precision operation where the quality of the finished grout determines the long-term performance, vibration characteristics, and service life of the machinery installation. An incorrectly grouted base plate — with voids, honeycombs, or grout that has shrunk away from the plate — will result in uneven load distribution, high-cycle vibration fatigue of anchor bolts, and premature failure requiring costly remedial work that may involve shutting down production. The correct MC-Grout 300 fluid-consistency grouting procedure involves six stages. Stage 1 — Substrate preparation. The concrete foundation surface must be prepared by mechanical means (scabbling, chipping, or grit blasting) to remove laitance, oil contamination, and weak surface concrete, exposing a clean, rough, and sound concrete substrate. Clean the surface thoroughly with compressed air. Pre-wet the prepared concrete surface with clean water to saturated surface dry (SSD) condition and remove standing water immediately before grouting — a dry concrete substrate will absorb water from the grout, causing local stiffening and void formation. Stage 2 — Base plate alignment and shimming. Install the base plate on temporary steel shims or wedges at the specified height and alignment. Set the shims at a minimum of four points (or as specified by the machinery manufacturer or structural engineer) to achieve the correct elevation and level as measured by precision level or laser. Check anchor bolt alignment against the base plate bolt holes. Stage 3 — Formwork installation. Install robust formwork around the perimeter of the base plate leaving a minimum grout head height of 50 mm above the underside of the plate (the grout must be poured to create a hydrostatic head that drives the fluid grout into all voids under the plate). Seal all formwork joints with foam sealant tape to prevent grout bleed. On one long side of the base plate, install a grout pour opening (typically a funnel or header box formed from plywood) at least 300 mm wide to allow the grout to be poured in bulk at a controlled rate. Ensure grout can exit on the opposite side by leaving a vent opening — blocked vents trap air under the plate. Stage 4 — Mix MC-Grout 300. Pour clean water (measured precisely to the specified dose — approximately 3.5 to 4.0 litres per 25 kg bag for fluid consistency, but check the current TDS as this varies by product grade) into a clean mixing drum. Add the MC-Grout 300 powder while the mixer is running and mix for a minimum of 5 minutes at high speed using a paddle mixer or forced-action mixer. Do not exceed the maximum water dose as this will reduce strength and increase shrinkage. Check the fluidity on a flow table (target greater than 250 mm) before placing. Mix only the quantity of grout that can be placed within 30 minutes at 20 to 25 degrees C. In Indian summer (above 35 degrees C), reduce the batch size further and use chilled mixing water. Stage 5 — Pour MC-Grout 300. Pour the mixed grout continuously into the header box on one side of the formwork. Do not interrupt the pour — stopping the grout flow midway allows partial setting and creates a cold joint under the plate. Pour at a steady rate allowing the grout front to advance uniformly from the pour side to the vent side. A grout bar (steel rod) can be used to gently assist the grout to travel under the full width of the plate, but do not vibrate. Grout to the required head height (minimum 50 mm above underside of plate). Stage 6 — Curing. Allow the grout to set (initial set approximately 3 to 4 hours at 20 degrees C). As soon as the grout is firm enough, apply a wet hessian or curing compound to all exposed grout surfaces and maintain curing for a minimum of 7 days. Remove formwork after 24 hours minimum and inspect the grout for voids at the plate perimeter. After full curing, remove the temporary shims — pack shim holes with non-shrink grout — and check the alignment of the base plate before commissioning the machinery.