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Nitrite diffusivity in calcium nitrite-admixed hardened concrete
The apparent diffusivities (Dapp) of nitrite in concrete were estimated by monitoring time-dependent concentrations of nitrite leached into water from calcium nitrite-admixed hardened concrete specimens. Experiments were conducted with five different concrete mixes and with deionized water (DI), limewater, or synthetic seawater as the leaching agents. The Dapp in Type II Portland cement concrete for long curing times and a w/c ratio of 0.40 was (similar to) 1.7 x 10-8 cm2/s when leached at 22 degree C with limewater. The Dapp was relatively insensitive to nitrite dosage and to DI or limewater as the leaching agent, but an increase in the w/c ratio to 0.49, or an increase in temperature by (similar to) 14 degree C, increased Dapp by (similar to) 50%. A 20% Type F fly ash cement replacement reduced the apparent diffusivity by (similar to) 60%. The Dapp decreased with concrete curing time. The magnitude of the Dapp and its dependence on concrete and exposure parameters were comparable to those observed in the transport of chloride ions in concrete.
Nitrite diffusivity in calcium nitrite-admixed hardened concrete
The apparent diffusivities (Dapp) of nitrite in concrete were estimated by monitoring time-dependent concentrations of nitrite leached into water from calcium nitrite-admixed hardened concrete specimens. Experiments were conducted with five different concrete mixes and with deionized water (DI), limewater, or synthetic seawater as the leaching agents. The Dapp in Type II Portland cement concrete for long curing times and a w/c ratio of 0.40 was (similar to) 1.7 x 10-8 cm2/s when leached at 22 degree C with limewater. The Dapp was relatively insensitive to nitrite dosage and to DI or limewater as the leaching agent, but an increase in the w/c ratio to 0.49, or an increase in temperature by (similar to) 14 degree C, increased Dapp by (similar to) 50%. A 20% Type F fly ash cement replacement reduced the apparent diffusivity by (similar to) 60%. The Dapp decreased with concrete curing time. The magnitude of the Dapp and its dependence on concrete and exposure parameters were comparable to those observed in the transport of chloride ions in concrete.
Nitrite diffusivity in calcium nitrite-admixed hardened concrete
Liang, H. (author) / Li, L. (author) / Poor, N.D. (author) / Sagues, A.A. (author)
Cement and Concrete Research ; 33 ; 139-146
2002
8 Seiten, 16 Quellen
Article (Journal)
English
Nitrite diffusivity in calcium nitrite-admixed hardened concrete
| British Library Online Contents | 2003
Nitrite diffusivity in calcium nitrite-admixed hardened concrete
| Elsevier | 2002
Nitrite diffusivity in calcium nitrite-admixed hardened concrete
| Online Contents | 2003