A.Jay Meunier, contracting specialist at S.T. Griswold and Co., a ready-mixed concrete supplier in Williston, Vt., responds: I am not aware of any cure for spalling slabs. Spalling can be caused by poor weather conditions during finishing, improper finishing techniques, or damage from de-icing salts.

Spalling slabs are more common in climates with frequent freeze-thaw cycles. Such climates require the use of air-entrained concrete (concrete with small bubbles of air to provide room for expansion when moisture freezes). Assuming that air-entrained concrete was used, most spalling problems can be traced to errors during the pour. Either the...

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