Grouting and Chocks
M&M will install your chocking system according to your
specification and needs, whether it be full bed grout, epoxy chocks, steel chocks and sole
plates, or the newer composite material chocks such as the adjustable Tri Chocks and
Vibratherm shimmable chocks.
For a better understanding, it is helpful to analyze the
different types of grout.
Inorganic grouts are by far the oldest grouts and are used in a broad range of industrial applications. Sometimes referred to as sand and cement grouts, which are mixed with water, this description does not do justice to the sophisticated properties some modern-day, proprietary brands possess. Plain sand, cement and water mixtures shrink. By the addition of other materials to the formula, however, the natural shrinkage can be offset by various expansive mechanisms. The resulting product will actually expand very slightly, in the range of .03%.
Since a lot of the shrinkage and expansion reactions take place in the plastic stage, before final cure, some expansive formulations can lose part of the net gain against shrinkage when the hydration process moves beyond the plastic stage. There are even proprietary brands that offer double expansive mechanisms, with the second taking over in the later stages of cure.
Certainly such formulations are much more complex than a simple sand and cement mixture. The formulator's goal is to produce a product that, when properly mixed and installed, will provide excellent base plate contact (95 to 100%), good compressive properties (5,000 to 8,000 psi) and the ability to be installed in a range of environments from 50 to 100 F.
Resistance to weathering and to operating or environmental fluids is another important property that must be considered in selecting an inorganic grout. The resistance capability of the grout is often the limiting factor to achieving a long, trouble-free life.
In a lot of industrial applications, a good inorganic grout will be stronger and more dense than the underlying concrete foundation. Being less expensive, by perhaps 30% to 50% of what an organic-based epoxy grout costs, inorganic grouts are used quite broadly where operating conditions permit.
The second general class of grouts is called organic because a polymer binder, which is organic, is substituted for the cement binder in an inorganic grout. Organic grouts often contain the same inorganic fillers (sand, silica flour and quartz) found in pure inorganic cement grout formulas.
If inorganic grouts are stronger than concrete and cheaper than organic grouts, why even use an organic grout?
The reason is very simple; the organic grout gives much better chemical resistance which allows it to perform where inorganic grouts can't. Even something as simple as lubricating oil can eventually destroy the physical properties of inorganic grouts.
Organic grouts are also stronger in compressive, shear and tensile strength, so they can perform longer under heavy dynamic loading conditions. There is a place for this more expensive class of grout in machinery grouting, particularly for right angle drive reciprocating compressors, large diesel and gas engines, some turbines and gear boxes, as well as a host of equipment in the steel and paper industries where wet operating conditions are prevalent.
Organic grouts, also called polymer grouts, are usually based on a thermosetting plastic resin system, such as epoxy. Other thermosetting resins, such as polyesters, phenolics and furanes, have been used as well. These materials are used in specialty grouts requiring a particular resistance to strong chemicals beyond the usually good chemical resistance offered by epoxies.
The most common type of organic grouting systems are based on epoxy resins. Because of the popularity of this class of grout, we will deal with the proper use and application of epoxy grouts. These grouts can be summarized as having almost no shrinkage, compressive strengths of 10,000 to 14,000 psi or better, tensile strengths of 2,000 psi or better, and they are essentially impervious to penetration or chemical attack by oils, detergents, water, mild acids and most alkaline solutions. However, with a coefficient of expansion of at least twice that of concrete and steel, care in the design, use and installation of epoxy grouts that must be taken.