Masonry Magazine October 2008 Page. 38
MORTARS
All contractors are looking for ways they can decrease labor costs, given that the material costs are going up. King continues, "We get a lot of requests for pre-blended pigmented mortars. The thing with pre-blended mortars, particularly with pigmented mortars, is that you'll see more consistency in colors, which you don't always get from field mix. I was recently on a jobsite where they didn't use pre-blended pigmented mortars; they field-mixed all their pigments. Three sections of the wall were a nice, dark gray color, the next section was a much lighter gray, and the following section was back to dark gray. You could tell there was a color variation between the segments that were done."
Nick Blohowiack, central regional manager for Spec Mix in Green Bay, Wisc., agrees. "What's been happening over the last 10 to 15 years is that mortars have been shifting from what once worked for portion based mortars, typically proportioned in the field, for example, a bag of cement to a half bag of lime to four and one-half cubic feet of sand. That's a type S proportion mortar. With the advent of factory pre-blending facilities, we can now take that a step further and go into prescriptive mortars where we can design mortars to physically match masonry units and/or applications. So, they work better with the masonry units, and that's important, since the masonry units have been changing over the years."
Various standards are in place to determine which formula is right for the job based on environmental, strength, stress and other factors. Picking the right pre-blend can be a challenge as new masonry units and standards come out. Quikrete's Leonard explains, "At the beginning of every job, we will read the specs, supply the submittal package that would include what mortar is to be used that best matches that specification, and then we do a pre-construction panel, and some of them lately are pretty sizable. Some test panels require that even the window units be inside, so the architect can get a full feel for what the wall is going to look like with some of the other variables."
Products such as manufactured stone veneers and concrete brick add to the challenges. Bill Kjorlien, masonry technical sales manager for Lafarge North America in Atlanta, says, "The ASTM (ASTM International, originally known as the Ameri-
Product Watch
Anti-efflorescence Additive for Cement-based Mortar Systems
Elotex has introduced ELOTEX ERA100, a re-dispersible powder additive designed to eliminate primary efflorescence in stuccos, tile grouts, skim coats cement powder paints and other cement-based mortar systems.
A highly active, resin-based anti-efflorescence compound, ELOTEX ERA10 exhibits good mixing properties, is compatible with other additives, and has no detrimental effects on working properties. When cured, ELOTEX ERA100 eliminates or drastically reduces the occurence of primary efflorescence and increases water repellency. IMAS
For more information, visit www.nationalstarch.com.
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36 Masonry
October 2008 www.masoncontractors.org
The Voice of the Masonry Industry