Use of entrained air concrete exposed to chlorides in non-freeze thaw environments

Concrete Under Severe Conditions, Two Volume Set ◽

10.1201/b11817-58 ◽

2010 ◽

pp. 503-510

Keyword(s):

Freeze Thaw ◽

Entrained Air

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Les effets des caractéristiques du réseau de bulles d'air, du type de mûrissement, du truellage de surface et de la fumée de silice sur la résistance à l'écaillage d'un béton à haute performance

Canadian Journal of Civil Engineering ◽

10.1139/l96-935 ◽

1996 ◽

Vol 23 (6) ◽

pp. 1260-1271

Author(s):

Richard Gagné ◽

Yvon Latreille ◽

Jacques Marchand

Keyword(s):

Silica Fume ◽

High Performance ◽

High Performance Concrete ◽

Surface Finishing ◽

Air Bubbles ◽

Concrete Durability ◽

Freeze Thaw ◽

Spacing Factor ◽

Entrained Air ◽

Scaling Resistance

In Canada, high-performance concretes (HPCs) are increasingly used in construction and repair, particularly for its durability, which is distinctly superior compared with ordinary concrete. The current tendency is to provide for a spacing factor of air bubbles lower than 230 μm in all HPCs that are subjected to freeze–thaw cycles. This choice is basically the outcome of an ongoing controversy as to the necessity of providing a good network of entrained air bubbles to protect HPCs against freeze–thaw cycles. In the future, the optimal use of HPC will depend, among other factors, on a better understanding of minimal requirements regarding the characteristics of air voids to ensure a good behavior of HPCs under freeze–thaw cycles. The results of the investigation reported herein show that a spacing factor lower than approximately 500 μm can be sufficient to ensure a good resistance of HPCs to scaling. It is also shown that surface trawling, slump, and set-retarding agents have only secondary effects on the scaling resistance of HPCs. Silica fume and membrane curing have allowed to improve significantly the scaling resistance of the HPCs under investigation. Key words: high-performance concrete, durability, scaling, set-retarding agent, silica fume, surface finishing, curing, pumping, entrained air, spacing factor.

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La durabilité au gel des bétons à haute performance

Canadian Journal of Civil Engineering ◽

10.1139/l92-116 ◽

1992 ◽

Vol 19 (6) ◽

pp. 975-980 ◽

Cited By ~ 2

Author(s):

Michel Pigeon ◽

Richard Gagné ◽

Pierre-Claude Aitcin ◽

Marcel Langlois

Keyword(s):

Silica Fume ◽

Standard Procedure ◽

Cement Ratio ◽

Water Cement Ratio ◽

Freeze Thaw ◽

Spacing Factor ◽

Thaw Cycle ◽

Entrained Air ◽

Air Void ◽

Limiting Value

Frost resistance of high-strength concrete (80–100 MPa) was studied by subjecting 44 concrete mixes to freeze–thaw cycles in water (ASTM C666, standard procedure A) and to scaling tests in the presence of deicer salts (ASTM C672, standard). The test programme was designed to analyze the effects of the water/cement ratio, the type of cement, the type of coarse aggregate, the duration of curing, and the air-void spacing factor. Results demonstrate that the water/cement ratio limiting value, below which entrained air is no longer necessary to protect concrete against freeze–thaw cycles, is sometimes higher than 0.30 but is more often below 0.25. This limiting value is affected most by cement characteristics: type 30 cement yielded much more durable concretes. Laboratory scaling tests demonstrated that when water/cement ratios are less than 0.30, the resistance deicer salt is generally very good, no matter what are the type of cement, the silica fume content, or the air-void spacing factor of the concrete. Key words: durability, freeze–thaw cycle, silica fume, scaling, curing, spacing factor, water/cement ratio, compressive strength, cement type, entrained air, aggregate. [Journal translation]

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