A platform for research: civil engineering, architecture and urbanism
A platform for research: civil engineering, architecture and urbanism
Gas and Water Permeability of Concrete for Reactor Buildings Small Specimens. Small Specimens
The effect on permeability of artificial aging by drying shrinkage and by freeze-thaw was determined by observing mass transfer of gas and water under a pressure gradient. It was found that damage due to freeze-thaw was negligible but that cracking around aggregate caused by drying shrinkage resulted in significantly increased permeability to both gas and water. The absence of freeze-thaw damage was attributed to self-dessication. Since the concrete was not exposed to an external source of water, the chemical reaction was sustained by consumption of mixing water. The resulting air voids were, apparently, sufficient to absorb expansive pressures due to ice formation. The response to lateral prestress was different for cracked and uncracked concrete. Although, in all cases, increased prestress resulted in reduced leakage, the effect was stronger in cracked concrete. Mean pore diameter as determined by gas diffusion was not, however, substantially affected because the leakage in cracked concrete remained very low. Reinforcing steel did not have a great influence on permeability of small specimens. Gas transmission through concrete was strongly influenced by moisture content. Free moisture constituted a barrier to gas flow, acting as a virtual solid. This is important since aging of concrete results in reduced free moisture. Ultrasonic pulse velocity appeared to vary with moisture content and porosity of concrete in the same way as gas permeability and gave promise of being effective for in-situ monitoring of concrete in reactor buildings. (Atomindex citation 20:007845)
Gas and Water Permeability of Concrete for Reactor Buildings Small Specimens. Small Specimens
The effect on permeability of artificial aging by drying shrinkage and by freeze-thaw was determined by observing mass transfer of gas and water under a pressure gradient. It was found that damage due to freeze-thaw was negligible but that cracking around aggregate caused by drying shrinkage resulted in significantly increased permeability to both gas and water. The absence of freeze-thaw damage was attributed to self-dessication. Since the concrete was not exposed to an external source of water, the chemical reaction was sustained by consumption of mixing water. The resulting air voids were, apparently, sufficient to absorb expansive pressures due to ice formation. The response to lateral prestress was different for cracked and uncracked concrete. Although, in all cases, increased prestress resulted in reduced leakage, the effect was stronger in cracked concrete. Mean pore diameter as determined by gas diffusion was not, however, substantially affected because the leakage in cracked concrete remained very low. Reinforcing steel did not have a great influence on permeability of small specimens. Gas transmission through concrete was strongly influenced by moisture content. Free moisture constituted a barrier to gas flow, acting as a virtual solid. This is important since aging of concrete results in reduced free moisture. Ultrasonic pulse velocity appeared to vary with moisture content and porosity of concrete in the same way as gas permeability and gave promise of being effective for in-situ monitoring of concrete in reactor buildings. (Atomindex citation 20:007845)
Gas and Water Permeability of Concrete for Reactor Buildings Small Specimens. Small Specimens
R. H. Mills (author)
1986
77 pages
Report
No indication
English
Radiation Shielding, Protection, & Safety , Reactor Materials , Construction Materials, Components, & Equipment , Construction Equipment, Materials, & Supplies , Radiation Pollution & Control , Materials Degradation & Fouling , Concretes , Containment Buildings , Gases , Nitrogen , Permeability , Ultrasonic Testing , Water , Foreign technology , ERDA/360603 , Nuclear power reactors
Permeability of cracked concrete specimens
TIBKAT | 1984
Parameters influencing water permeability coefficient of cracked concrete specimens
| British Library Online Contents | 2017
Parameters influencing water permeability coefficient of cracked concrete specimens
| Online Contents | 2017