Masonry Magazine October 2011 Page. 25
The American Society for Testing Materials (ASTM)
The American Society for Testing Materials (ASTM) C936/C936M-09 defines the industry manufacturing standard for solid concrete interlocking pavers. This Standard Specification requires, in part:
• An average absorption no greater than 5 percent
• An average compressive strength of 8,000 pounds psi
• No greater mass loss than 200 g/m2 when subject to 25 freeze-thaw cycles
• No greater mass loss than 500 g/m2 when subject to 50 freeze-thaw cycles.
In areas where pavers are exposed to freezing and deicing materials during their service, ASTM C936/C936M-09 requires testing the pavers in 3 percent saline solution to replicate the effects of deicing salts. When companies meet ASTM requirements, their pavers are considered resistant to deicing salts. Pavers from Belgard, for example, exceed this standard and are deicing salt resistant, but that does not make them deicing salt proof. In fact, no company's pavers are deicing salt proof.
One challenge the paver industry faces is potentially confusing advertising that can cause contractors, hardscapers and homeowners to believe that some branded pavers are guaranteed to be unaffected by deicing salts. Product statements such as "deicing salt resistant," while technically true, also can be misunderstood.
"Customers sometimes take 'deicing salt resistant to mean 'deicing salt proof," says Daniel Moreland, a Belgard architectural representative for Anchor Concrete Products in Easton, Pa. "But there is a big difference between deicing salt resistant and proof."
Another claim sometimes misread by hardscape professionals and homeowners is a warranty that covers against the abnormal deterioration of a surface due to sodium chloride (NaCl), such as deicing salt. Such warranties cover only abnormal deterioration, which is damage that would exceed the allowances made in ASTM C936/C936M-09.
To eliminate confusion, manufacturers should explain carefully their guarantees to customers. For example, if pavers do sustain deicing damage, warranties typically don't cover items such as labor costs to replace them, shipping costs for the replacement pavers, and color matching. Professionals and homeowners who believe their pavers are protected against any and all damage caused from deicing salts could be unpleasantly surprised.
SAFEGUARD
AGAINST DAMAGE
One of the best ways to protect pavers is to minimize their exposure to deicing salts. Although people tend to believe that more salt equates
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