Proper Job Planning
Earlier issues of this
covered topics such as
"What is Grout",
"The Different Types of Grout",
and "Foundations-Preparation for Grouting".
Planning the Pour
Planning the grout pour is
one of the most important steps
necessary to insure a good grout
installation. Many steps need to
be taken early in the job
schedule, several days ahead of
actual grouting in some cases.
Items such as the following fall
into this category:
- Provide shade from
direct sunlight over the
equipment and foundation
at least forty-eight (48)
hours prior to grouting.
This is usually required for
proper alignment of the
equipment as well.
- If temperatures are likely to drop below 50°F., additional shelter and heat will be needed to achieve temperature equilibrium of the foundation and the equipment to a minimum of 70°F. Start early enough in the job schedule so that both alignment and grouting can be done under reasonably stable temperature ranges.
- Be sure the grouting materials are stored ahead of time in an area or room where they will be in the 70° F. range. Grout materials that are stored outside may be too cold or too hot and this will affect both workability and performance. Grout materials should be dry, as well.
- When using epoxy grouts the area to be grouted must be bone dry. The foundation should be protected from rain and dew in advance so the concrete will be thoroughly dry. Concrete can hold moisture several inches below the surface, which may appear to be dry. The moisture below the surface can be drawn to the surface during the cure of the epoxy grout. Moisture will interfere with the bond between the epoxy grout and the concrete foundation. The ASTM D 4263-83 test can be used with existing foundations to determine if the concrete is dry enough for epoxy grout.
- Develop a grouting plan so that any early grout pours, such as leveling pours or those in connection with anchor bolt replacement or jack pockets, will be done early in the grouting schedule. They should be cured and able to take loads if required for alignment purposes. Often, a jackscrew landing plate must sit on a deeper grout pour, and a deep, partially cured first pour can allow changes in the jackscrew plate during subsequent alignment.
- When regrouting old equipment, plan ahead of time how the foundation will be rebuilt to the approximate elevation of the original concrete block. Whether rebuilding with concrete or the new 24-hour curing polymer-modified concrete (to be discussed in a future newsletter) or rebuilding with epoxy grout, this will affect the job schedule. Curing times for these products vary from 24 hours to 28 days.
- Decide early if rebar reinforcing and expansion joints will be required and in which pours. This is a very important part of preplanning. Follow the manufacturer's instructions in this regard. General tips on these two topics will be in a subsequent newsletter.
The Final Pour
Implied in the above suggested steps of early planning is a principle of good grouting practice: to make the final or precision pour in the 2" maximum thickness range, under the equipment base or sole plate. Naturally, the final pour will be thicker on the shoulder in the case of epoxy grouts since they can be poured high along the side of the equipment base or sole plate. (Cementitious grouts should be cut off flush with the bottom of the equipment base and sloped away from the equipment.)
If the total of the two grout pours is to be 8" deep, they should be done 6", then 2", rather than two 4" pours. There will be less pull down of the equipment base during bolt torquing if the final pour is limited to 2". Good materials and installation techniques should result in pull downs of .0015" or less in most cases. Some pull-down is to be expected, and it is the summation of any changes that take place during bolt torquing, in the anchor bolts, sole plates (if used), subpours, as well as the final precision grout pour. There is no hard-and-fast rule on what is acceptable. What is important is that the crankweb deflections or coupling alignment and the machined leveling pads stay within tolerances for the type of equipment being grouted.
Newer adjustable support systems are gaining favor since these assemblies will allow the alignment to be adjusted for thermal growth after grouting. This is a real plus if proper hot running alignment is not obtained even with good cold alignment settings. Information on these systems is available on request. The Day of the Pour On the actual day of grouting, it is a good idea to review the day's grouting plan with the grout crews. This can be done while the final alignment check is being performed by mill-wrights. Subjects which should be discussed are as follows:
- Review the manufacturer's mixing instructions and installation procedures. Assign responsibility to one person for proper mixing.
- Review safety and hygiene precautions.
- Decide on who will do what job. Crews to carry the mixed grout to the equipment, as well as placement crews, will be needed.
- Good grouting practice is to start at one end and pour grout towards the other, expelling air from under the equipment as it fills up. Select which end to start from. Also, if one side of the equipment is harder to grout than the other, start there first while the crew is fresh.
- Be sure the equipment is ready for grouting. The metal surfaces that will be in contact with the grout should be properly prepared, sandblasted, etc. Check the concrete for proper chipping and cleanliness, and if using an epoxy grout, the dryness of the concrete. Check the forms for tightness. Have a flashlight, rags, foam or putty available in case there is a small form or grout dam leak. Bracing lumber and a Port-a-Pack hydraulic jack will be needed if there is a major leak. Be prepared for the worst.
- Forms should have been waxed earlier. If the wax has evaporated, reapply, but don't get it on the concrete or equipment base. Paste wax is best.
- Protect the floors and nongrouted equipment surfaces ahead of time to make clean-up easier. Grouting is messy.
- Check anchor bolt sleeves and jack bolts to be sure they are properly sealed or wrapped. Ensure that anchor bolt sleeves are dry.
- Check the mixer(s) and have carrying buckets, wheelbarrows, etc., clean and available. Prepare placement tools ahead of time, such as plywood strips 4" wide, or funnels for skid grouting.
- Be sure everyone knows his job, and stress the importance of placing the grout thoroughly back under the equipment but without forcing air under it. Work slowly and deliberately without stopping. No breaks should be taken during grouting. Once a part of the frame is full or in complete contact with the grout, do not allow grout level to drop and let air in. Keep more material coming and work progressively to the other end. After the Pour · Clean up immediately after grouting; the floor, the equipment and yourself. Assign one or two persons to finish the installed grout surface before it gets too hard to finish, in accordance with the grout manufacturer's instructions. Some slow curing materials will require someone to stay late and to periodically refinish if bubbles continue to break out on the surface after placing.
- When grouting with epoxy or other organic materials, as well as cementitious materials, wash up thoroughly after grouting, even intermittently on long jobs. Waterless hand cleaners and soap and water are best. Finishing or cleaning solvents can be harmful to the skin. Follow the manufacturer's instructions for the brand material involved, and use good common sense. Cover this in the planning session!
Rowan Grouting Inspection/Job Supervision is available for any project with critical equipment grouting and installation. Contact us for a rate sheet and estimate for site inspection. Additionally installation drawing and plan review is also available for smooth installations and to ensure they meet latest design guidelines.