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 CompCon creates a platy crystal formation of the calcium hydroxide system that has a greater surface area than the needle-like surfaces of an ettringite system such as that developed with a Type-K cement and/or a CSA (calcium sulfoaluminate) ettringite system. Therefore the expansion of a CompCon calcium hydroxide platelet system tends to be greater, and thus less material is necessary to obtain the same RE (Restrained Expansion) than with an ettringite system when tested in accordance with ASTM C-878. The addition of CompCon to a concrete mix provides a predetermined percentage of CALCIUM OXIDE and ALUMINUM DIOXIDE, plus certain other chemical compounds that will react with specific elements found in the concrete to form CALCIUM HYDROXIDE PLATELETS. The amount of platelets produced, thus the percentage of restrained expansion (RE), is regulated by the amount of CompCon introduced into the mix. There are certain "urban (construction) legends" and misconceptions relative to the rate and amount of expansion that occurs during the the first 24 hours of curing. Some shrinkage compensating concrete proponents are of the opinion that if the rate of expansion is “too fast”, there is an initial slippage and loss of RE (restrained expansion) in the concrete. They believe that the rate of expansion should occur over several days of wet curing after the concrete has set up. This is necessary in a Yype K ettringite system, but not in a Type G calcium hydroxide system. This hypothesis has some theoretical validity, but is a moot point and non issue in practice. There are separate design curves for Type G and Type K systems in ACI 223 relating reinforcing restrain to require mix expansion. The differences between these two graphics accounts for the difference in expansion rates of the Type G and Type K systems. Following ACI 223 will ensure identical results when using either system. If the initial set time of the concrete is retarded greater than 8-10 hours, the amount of loss of RE during this extended set time should be compensate for by increasing the dosage of the CompCon component. The increased dosage will produce a greater RE that will allow (compensate) for the possible loss during the early stage of extended setting. CompCon has its RE achieved during the first 24 to 48 hours, depending upon the cement in use. CompCon is compatible with virtually all cements meeting ASTM C-150, including, but not limited to Types I, II, III, IV, V, LA, IP, IA, & slag cement. CompCon can also be used with fly ash, silica fume, and most other concrete additives. | What is CompCon | Chemistry | Concrete Characteristics | Facts about SCC | CompCon & Floor Slabs | Pre-Stressed | Links | | Return Home | Products | What's New | Our Services | Contact Us | |
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