Page 90 - Machinery Component Maintenance

Machinery Foundations and Grouting 75

It would also be prudent to prepare simple, itemized field checklists to
be used by personnel involved in equipment installation and grouting.
Typical sample checklists can be found in the appendices at the end of
this chapter.
Table 3-2 is a materials check list for epoxy grouting. Orders for mate-
rials not available locally should be placed with lead time reserved for
order processing, packaging, shipping, etc. A good rule-of-thumb is to
place orders sufficiently in advance to allow three times the normal time
required for unencumbered transit, if it can be anticipated that materials
are available from stock.
All grouting materials should be stored indoors in a dry area and pref-
erably at room temperature. Containers stored outside may in the sum-
mertime reach temperatures as high as 140°F, particularly if the contain-
ers and bags are in direct sunlight. The speed of most chemical reactions
is doubled with each 10°C (I 8°F) rise in temperature. Consequently, it is
quite probable that epoxy grout that has been stored outside in the sum-
mertime will have an excessively hot cure. When this occurs, the grout
cures in a thermally expanded state, and after cooling, creates locked-in
stresses. Excessive cracking will result as these stresses are relieved.
Most epoxy formulations do not cure well without accelerators at tem-
peratures below 6O"F, and not at all at temperatures below 35°F. Conse-
quently, grouting materials stored at cold ambient temperatures require
several days to cure. When this occurs, it is possible that equipment
alignment conditions will change before the mortar has set, resulting in a
poor installation. Furthermore, when the mortar is cold, it is viscous and
very difficult to place.

Conventional Grouting

Concrete Characteristics
Foundation design and machinery installation require more expertise
and precision than are usually practiced. Perhaps due to a shortage of
skilled manpower, the construction industry has given less attention to
technical details. Since there is generally some knowledge- "Everybody
knows a little bit about concrete; and aren't foundations just big blocks of
concrete?"-grouting is often taken for granted. Consequently, a high
percentage of compressors are installed improperly. Many foundations
must be renovated or the equipment regrouted long before the life of the
equipment is exhausted. Here are a few common problems that can be
avoided by putting a little effort into proper design and installation.