Frequently Asked Questions

A mechanical engineering contractor in Greater Noida is installing two 500 kW centrifugal compressors on reinforced concrete pedestals in an industrial facility — the machinery OEM specification requires a precision non-shrink grout with minimum 40 MPa compressive strength and zero shrinkage to achieve the required vibration isolation and bearing life — what is the complete MC-Grout 300 installation methodology including pedestal preparation, formwork setting, grout mixing, pouring sequence, and curing, and how does the contractor verify non-shrink performance on site?

Machinery base plate grouting is a precision engineering task where errors in grout preparation or application can result in premature bearing failure, increased vibration levels, and misalignment of the compressor shaft with consequent mechanical damage — the stakes are higher than most structural concrete work. The complete MC-Grout 300 installation methodology is as follows. Pedestal surface preparation: the concrete pedestal surface must be prepared by roughening (light scarifying or jackhammer chiselling to produce a CSP 3 to CSP 5 profile per ICRI 310.2), removing all laitance, oil, grease, and curing compound from the bearing surface — any contamination will prevent grout adhesion and cause the grout pad to delaminate under vibration loading. Blow clean with compressed air. Pre-wet the pedestal surface to saturated-surface-dry (SSD) condition minimum 4 hours before grouting — this prevents the dry concrete from absorbing water from the grout mix and causing premature stiffening in the gap. Do not allow puddles of standing water in the gap at the time of grouting. Checking pedestal level and elevation: after anchor bolt installation and before base plate placement, verify pedestal top level with a precision level to within plus or minus 2 mm — if the pedestal top is significantly uneven, apply a levelling layer of MC-Grout 300 or gypsum packing to achieve a level bearing surface for the base plate jacking. Base plate installation and alignment: using hydraulic jacks or precision jack screws, raise the compressor base frame to the correct elevation and alignment as specified by the OEM alignment procedure (typically within 0.05 mm of specified elevation and 0.02 mm per metre of levelness). Support the base frame on temporary levelling screws or steel packs at the four corners and at intermediate points to prevent deflection under its own weight. The gap between base plate underside and pedestal top should be 40 to 60 mm — this is the standard grout gap for heavy machinery; gaps less than 20 mm are difficult to fill completely and gaps greater than 80 mm require two-stage grouting. Formwork installation: erect formwork around the entire perimeter of the base plate to contain the grout. The formwork must be: sealed at the base to the pedestal surface with putty or foam strip (no grout leakage); set back 25 to 50 mm from the base plate edge to allow grout to flow under the plate; chamfered at the top to allow grout to flow in from the pouring head without air entrapment; provided with one or more overflow holes at the far side from the pouring position at the level of the grout soffit to indicate when grout has flowed completely under the base plate. Head box installation: on one side of the base plate, erect a head box (a box 300 to 400 mm tall attached to the formwork) through which the grout is poured — the head of grout in the head box provides the hydrostatic pressure that drives the grout under the plate across the full width of the installation. MC-Grout 300 preparation: measure exact water volume per batch using a calibrated bucket — 4.2 litres per 25 kg bag for standard flowable consistency (check product data sheet for the current supply batch). Add the powder to the water (not water to powder) in a 60-litre drum or barrel and mix with a slow-speed (400 rpm) paddle mixer for 3 minutes until completely smooth with no lumps. Do not add extra water to improve flow — excess water increases shrinkage and reduces strength. Pour and place: pour the mixed MC-Grout 300 continuously into the head box without stopping — do not allow the flow to stop mid-pour as this can trap air. Continue pouring until grout flows out of the overflow holes on the far side of the base plate. Do not vibrate — vibration of non-shrink grout destroys the expansion mechanism and is counterproductive. Allow the grout level in the head box to maintain a standing head of 200 to 300 mm above the base plate bearing surface throughout the pour to ensure complete filling. After grouting: leave the head box in place for 2 to 4 hours (until initial set) before removing — this maintains the head pressure during the early hydration period when the expansion is most important. After removal, finish the grout exposed edges and seal with wet burlap or polythene sheet for 7 days curing. Remove formwork after 24 to 48 hours and finish exposed grout faces. Non-shrink performance verification on site: the contractor verifies non-shrink performance by casting three 100 mm cubes in a standard test procedure using the same mix water content as the field grouting — tap the moulds gently on a vibrating table for 10 seconds only (to remove air bubbles without destroying expansion) — demould at 24 hours and store in water at 23 degrees Celsius until testing. Measure height of cubes at 3, 7, and 28 days with a micrometer — height should be equal to or greater than the 24-hour dimension at all ages (zero or positive dimensional change). Report 28-day compressive strength. For critical machinery installations, conduct additional acceptance testing by drilling 50 mm diameter cores through the grout pad 28 days after installation and inspecting the core for voids — a grout pad with zero or near-zero voids indicates complete filling. Space Arc Engineering supplies MC-Grout 300 and technical grouting support for machinery base plate, bridge bearing, and column base grouting projects in Greater Noida, Ghaziabad, Delhi NCR, and across Uttar Pradesh.