If you properly get the vibration out of the equipment, its reliability will increase by a factor of 8 to 10 times.
Assuming the concrete is properly cured, grout can be poured after all concrete laitance is removed.
A concrete foundation should be prepared for grout by removing all laitance with a chipping hamper with a chisel bit.
Remove all laitance with a chipping hammer.
Make sure the concrete is properly hydrated.
Be sure the concrete is free of any oil or contaminants.
All existing foundation contamination must be removed by removing the concrete that is contaminated prior to grouting.