Masonry Magazine January 2007 Page. 49
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no sheet wrap
or vapor barrier
can touch.
Masonry units should always be stronger than the mortar to prevent them from cracking in tandem with the admixture added by manufacturers to concrete masonry units (CMUs) to help masonry walls repel water and control efflorescence.
"They go hand in hand. The efflorescence benefit that you get is due to the water repellency," Jablonski said. "A water repellant also offers efflorescent control."
SPEC MIX's Integral Water Repellent (IWR) is a pre-blended mortar mix that contains a water repellant admixture and controls efflorescence. "It's a standard mortar, and we added the admixture," Blohowiak said. "IWR helps the mortar physically repel the water."
Hycrete Incorporated in Jersey City, N.J., offers a water-based liquid admixture that's mixed in the field and forms a waxy residue to prevent water penetration into the finished wall.
"It forms a chemical bond to metals in the concrete. It makes the joints water tight," said David Rosenberg, CEO of Hycrete. He added that, although the admixture is mostly used on concrete walls, it could also be used in masonry mortar mixes.
BASF Admixtures Inc., in Cleveland, which acquired Degussa's construction chemicals business in July 2006, offers one water repellent admixture for concrete block and another for masonry mortar. The admixtures have a polymer additive that increases the color integrity.
"Rheopel WR admixture enables the production of visually appealing concrete masonry products that are water-penetration resistant and efflorescence-controlled," according to the company. "This unique, patented formula incorporates a specially blended, high-molecular weight, polymer emulsion that improves and maintains color integrity."
While new innovations are giving water repellant admixtures increased compressive strength, more durabil-
PROSOCO
ROGUARD
Air & Water-Resistive Barrier
for sheathing and CMU backup
• Easy application and clean-up
• Minimal safety gear needed
Water-based, no VOC/EPA hassles
Stays on in rain, wind, sun, sleet and snow
• Helps buildings stay mold-free and energy-efficient
PROSOCO
SINCE 1939
800.255.4255
www.prosoco.com
See it at Booth C3806.
World of Concrete 2007
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The Voice of the Masonry Industry
January 2007
Masonry 43