Pacific Cast Stone Inc. of Lincoln, Neb., has announced that a 20-year Cast Stone Warranty is now a part of its product offering. The warranty covers damage involving cracking, spalling, freeze/thaw, crazing, iron spotting and alkali silica reactivity.
Jack L. Irwin, Chairman/CEO of Pacific Cast Stone, emphasized that this warranty was the result of over two years of research and testing of its products in collaboration with Wiss, Janney, Elstner Associates, Northbrook, Ill., and Thos. Rewerts & Co. LLC, Kansas City, Mo. Irwin said this development team was put together to address the durability issue regarding cast stone products in general. The knowledgeable engineers working in this field had expressed a great deal of concern regarding this durability issue and Pacific was determined to manufacture only products of the highest quality standards. WJE and Rewerts have commented that Pacific Cast Stone products in their now developed form should last hundreds of years.
One of the leading concerns of the engineers has been Alkali Silica Reactivity (ASR). This is a phenomenon in cement mixtures caused by a reaction between the hydroxyl ions in the alkaline cement pore solution in the concrete and reactive forms of silica in the aggregate. A gel is produced which increases in volume by taking up water, exerts pressure and results in failure of the concrete (cast stone). Irwin said Pacific has addressed this by incorporating granite as the aggregate in Pacific cast stone totally eliminating any ASR concerns.
Irwin also pointed out that prior to this development Pacific was only using the “wet cast process” for manufacturing cast stone. The engineers have commented that the “dry cast (dry tamp)” method with a 0 mix slump has had major durability and longevity issues. Evaluating projects that have Pacific cast stone in place for nine to 18 years are evidence of the superiority of the “wet cast” production method.