Frequently Asked Questions

Why is high early strength important for industrial machinery grouting and what does Conbextra BB92O achieve?

In industrial plants and process facilities, every hour of planned maintenance shutdown is expensive. When machinery such as pumps, compressors, turbines, or gearboxes must be removed for maintenance and then reinstalled, the machine cannot be safely started and loaded until the grouting under its base plate has cured to sufficient strength to carry both the static weight and the dynamic loads from vibration and rotating imbalance. With a standard cementitious grout that achieves adequate strength in 3 to 7 days, the entire shutdown programme must be extended to allow for grout curing. Conbextra BB92O achieves suitable strength within 24 hours, allowing the grouting to be completed as part of the final stage of the maintenance shutdown and the machine to be recommissioned immediately after the minimum cure period — significantly reducing the total shutdown duration and the associated production loss.

What is the difference between Conbextra BB92O and Conbextra BB92IN for bearing bed grouting?

Both Conbextra BB92O and Conbextra BB92IN are bearing bed grouts from the Fosroc Conbextra range, but they are formulated for different performance priorities. The BB92O suffix denotes the early-strength-optimised variant, where the formulation is designed to achieve the highest possible strength in the shortest time for rapid equipment return to service. The BB92IN variant is formulated specifically for performance under Indian ambient temperature conditions, which are frequently hotter than European reference conditions — particularly in summer when temperatures of 35 to 45 degrees Celsius are normal across Northern India. Both products are non-shrink and cementitious, and both are appropriate for industrial machinery grouting. The right choice depends on whether rapid return to service or consistent performance in hot Indian summers is the primary requirement — Space Arc Engineering can advise on the most appropriate Conbextra bearing bed grout for the specific project conditions.

How is the bearing gap prepared before grouting with Conbextra BB92O?

Proper substrate preparation is critical for any grouting operation. The concrete foundation surface must be mechanically roughened (by chipping, scabbling, or grit blasting) to expose aggregate and provide a mechanical key for the grout. Any loose concrete, oil, grease, or contamination must be removed. The prepared surface must be saturated surface-dry (SSD) before grouting — meaning the concrete is fully water-saturated but has no free surface water that would dilute the grout at the interface. The equipment base plate must be accurately levelled on shims or wedges to the required installation height before grouting, and the formwork surrounding the bearing gap must be oil-sealed to prevent grout leakage. The mixed grout is then poured or pumped from one side of the bearing gap, allowing air to escape from the other side, until the gap is completely filled with no voids.