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Study of the Effects of Post-Combustion Ammonia Injection on Fly Ash Quality: Characterization of Ammonia Release from Concrete and Mortars Containing Fly Ash as a Pozzolanic Admixture. Semi-Annual Technical Progress Report for the Period 4/12/01 to 10/11/01.

DE2004833656

Publication Date	2004
Personal Author	Rathbone, R. F.; Robi, T. L.
Page Count	30
Abstract	Work completed in this reporting period focused on the measurement of the rate of ammonia loss from mortar and concrete, and the measurement of ammonia gas in the air above the materials immediately after placement. The majority of mortar experiments have been completed, and testing has begun on concrete. The mortar experiments indicate that the rate of ammonia loss is greater in mortars prepared using a higher water content and water:cement (W:C) ratio, although the higher rate is primarily observed within the first 2 days, after which the loss rates are nearly the same. The source of low-calcium (Class F) fly ash exerted a negligible influence on the loss rate. However, mortar prepared using a higher-calcium fly ash evolved ammonia at a slightly slower rate than the Class F ash mortars. The data also indicate that an increase in ventilation increases the ammonia loss rate from mortar, and suggest that a well-ventilated space could substantially increase the loss of ammonia from mortar and, by inference, a concrete slab. Analysis of ammonia concentrations in the air above freshly-placed mortars in an enclosed space indicate that the fly ash ammonia concentration should not exceed 100 mg N/kg ash in confined space applications. For most other applications with some ventilation the maximum acceptable concentration would be approximately 200 mg/kg. Early results from experiments on concrete suggest that, under similar conditions, ammonia diffusion from concrete occurs at a higher rate than in mortar. In addition, increasing the slump of concrete through the use of chemical admixtures has only a minor effect on the ammonia loss rate.
Keywords	Concrete Ammonia Losses Measurements Environmental exposure Cements Fly ash Temperature Mixing Ventilation Mortars(Materials) Construction material Air pollution
Source Agency	Technical Information Center Oak Ridge Tennessee
Corporate Authors	Kentucky Univ., Lexington. Center for Applied Energy Research.; Department of Energy, Washington, DC.
Supplemental Notes	Sponsored by Department of Energy, Washington, DC.
Document Type	Technical Report
NTIS Issue Number	200516

Study of the Effects of Post-Combustion Ammonia Injection on Fly Ash Quality: Characterization of Ammonia Release from Concrete and Mortars Containing Fly Ash as a Pozzolanic Admixture. Semi-Annual Technical Progress Report for the Period 4/12/01 to 10/11/01.

Study of the Effects of Post-Combustion Ammonia Injection on Fly Ash Quality: Characterization of Ammonia Release from Concrete and Mortars Containing Fly Ash as a Pozzolanic Admixture. Semi-Annual Technical Progress Report for the Period 4/12/01 to 10/11/01.
DE2004833656

Publication Date	2004
Personal Author	Rathbone, R. F.; Robi, T. L.
Page Count	30
Abstract	Work completed in this reporting period focused on the measurement of the rate of ammonia loss from mortar and concrete, and the measurement of ammonia gas in the air above the materials immediately after placement. The majority of mortar experiments have been completed, and testing has begun on concrete. The mortar experiments indicate that the rate of ammonia loss is greater in mortars prepared using a higher water content and water:cement (W:C) ratio, although the higher rate is primarily observed within the first 2 days, after which the loss rates are nearly the same. The source of low-calcium (Class F) fly ash exerted a negligible influence on the loss rate. However, mortar prepared using a higher-calcium fly ash evolved ammonia at a slightly slower rate than the Class F ash mortars. The data also indicate that an increase in ventilation increases the ammonia loss rate from mortar, and suggest that a well-ventilated space could substantially increase the loss of ammonia from mortar and, by inference, a concrete slab. Analysis of ammonia concentrations in the air above freshly-placed mortars in an enclosed space indicate that the fly ash ammonia concentration should not exceed 100 mg N/kg ash in confined space applications. For most other applications with some ventilation the maximum acceptable concentration would be approximately 200 mg/kg. Early results from experiments on concrete suggest that, under similar conditions, ammonia diffusion from concrete occurs at a higher rate than in mortar. In addition, increasing the slump of concrete through the use of chemical admixtures has only a minor effect on the ammonia loss rate.
Keywords	Concrete Ammonia Losses Measurements Environmental exposure Cements Fly ash Temperature Mixing Ventilation Mortars(Materials) Construction material Air pollution
Source Agency	Technical Information Center Oak Ridge Tennessee
Corporate Authors	Kentucky Univ., Lexington. Center for Applied Energy Research.; Department of Energy, Washington, DC.
Supplemental Notes	Sponsored by Department of Energy, Washington, DC.
Document Type	Technical Report
NTIS Issue Number	200516