Special-Uses-Alkali - Expanded Shale & Clay

Bridger and Coal Creek power plants and Boral Material Technologies, Inc. Monticello andCraig plants. The fly ash from Boral’s Craig plant was modified with the company’s so called“FACT” treatment to neutralize the impact of activated carbon used to adsorb mercury from theflue gas stream of coal-fired power plants.4.2.1. Salt River Materials GroupSalt River Materials group provided the baseline Class F fly ash as chosen by CDOT, from theSan Juan generating station for testing and evaluation. This material was tested at the following 3different replacement levels: 10, 20, and 30% of cement corresponding to CDOT’s minimum andmaximum limits and a mid-point. The expansions after 14 days were 0.33%, 0.10% and 0.02%respectively. These expansions indicated a successful mitigation level of 21% cementreplacement for our mix verifications.4.2.2. Boral Material TechnologiesBoral’s Monticello Class F fly ash, as well as FACT-treated Craig Class F fly ash were alsotested. These fly ashes were tested at 10, 20 and 30% replacement of cement. The Monticello flyash exhibited expansions of 0.35%, 0.17% and 0.03% respectively after 14 days. The FACTtreatedCraig fly ash showed similar results with slightly less expansion with 0.29%, 0.13% and0.04% respectively. Based on this information, the mix designs will contain a 26% replacementof cement with the Monticello and 24% replacement with FACT-treated Craig Class F ashes.4.2.3. Headwaters IncorporatedHeadwaters Incorporated submitted two of its fly ash products for testing, Coal Creek and JimBridger plants. These fly ashes were also tested at 10, 20 and 30% replacement of cement.During the expansion testing, these bars seemed to exhibit lower strength. Some of the bars hadto be re-fabricated because they would break during the un-molding process. The Coal Creekgenerating station fly ash had expansions of 0.29%, 0.08% and 0.07% at the cement replacementlevels of 10%, 20% and 30%, respectively. The Jim Bridger generating station’s fly ash hadexpansions of 0.41%, 0.39% and 0.08% at the same replacement levels as the Coal Creek fly ash.These 14-day expansion results gave a cement replacement level of 19% for the Coal CreekClass F, and 28% for the Jim Bridger Class F in the mix designs.18