Air entrainment in fresh concrete and its effects on …

The total volume of the air voids in hardened concrete with fly ash microspheres tested by X-ray varies The Effects of Pumping on the Air Content and Void Structure of Air-Entrained, Wet Mix

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Impact of Concrete Placing Method on Air Content, Air …

Approximately 76 m3 (100 yd3) of ready-mixed, air-entrained concrete were placed in a parking lot and driveway at the Schwing America Manufacturing facility in White Bear, Minnesota, on June 21, 1994. This concrete was placed by means of a pump, crane and bucket, and truck-mounted conveyor, and came directly from the chute of ready-mix trucks. Pump configurations were used that allowed

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(PDF) EFFECT OF AIR VOIDS IN HIGH STRENGTH …

Aggr egate. The aggregate in high-strength concrete, will lead careful attention to aggregate size, shape, surface texture, mineralogy, and cleanness. For each s ource of aggregate and concrete

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Research - Concrete Pumping Effects on Entrained Air-Voids | WS…

2/7/1994 · The actual effect of pumping on the air content measured for the concrete is not consistent; in some cases air content has increased, while in others it has decreased. Previous work has shown that pumping causes pressure in the concrete, and this pressure can alter the air-void system.

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Research - Appendices: Concrete Pumping Effects on …

Title Appendices: Concrete Pumping Effects on Entrained Air-Voids Author William Elkey, Donald J. Janssen, Kenneth C. Hover Subject Admixtures, Air entraining agents, Air voids, Fly ash, Freeze thaw durability, Lignosulfonate, Mix design, Pressurization

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Research - Concrete Pumping Effects on Entrained Air …

Title Concrete Pumping Effects on Entrained Air-Voids Author William Elkey, Donald J. Janssen, Kenneth C. Hover Subject Admixtures, Air entraining agents, Air voids, Fly ash, Freeze thaw durability, Lignosulfonate, Mix design, Pressurization, Pumped concrete

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CONCRETE PUMPING EFFECTS ON ENTRAINED AIR …

The research described in this report investigated the impact concrete pumping has on air -entrained voids in concrete. The study examines the effects of different air contents, pumping time, and pressure has on the air volume and the stability of the air void

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Effect of Air Entrained Concrete on Strength of Concrete

Normal reduction in strength of concrete by use of air-entrained admixtures varies from 3 to 7%. This variation of strength shall be considered in the mix design of concrete so that a desired compressive strength is achieved with required amount of admixture and workability.

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Air entrainment in fresh concrete and its effects on …

8/3/2021 · Effects of raw materials, processing factors and environment on air entrainment in fresh concrete are reviewed. • The testing methods of air void system in concrete at fresh and hardened states are summarized. • Effects of air entrainment on properties of concrete at

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Effect of entrained air voids on the microstructure and …

1/10/2011 · The effects of entrained air on microstructure and transport properties of concrete with up to 11.5% air at different w/c ratios, curing and conditioning regimes were investigated. It was found that air voids disrupt the packing of cement and increase the heterogeneity of

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Appendices: Concrete Pumping Effects on Entrained Air-Voids

The actual effect of pumping on the air content measured for the concrete is not consistent; in some cases air content has increased, while in others it has decreased. Previous work has shown that pumping causes pressure in the concrete, and this pressure can alter the air-void system.

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Investigation on the effect of entrained air on pore …

19/7/2021 · The entrained air voids mainly protect concrete against freezing and thawing; but large entrapped air voids are not altogether beneficial to frost resistance. The Fig. 5 SEM images present the air voids observed in same size of zone for air-entrained mortars. The air

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Examination of Air Entrainment Stability Factors of Pumped Concrete

This report summarizes the findings pertaining to the effects of various factors on the pumping of air-entrained Portland Cement Concrete and the circumstances surrounding the loss of air that can occur during the pumping of fresh concrete. The

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Does air entrainment affect concrete strength? – …

3/4/2019 · Intentionally entrained air voids improve the resistance of concrete to damage from cycles of freezing and thawing. Any air voids reduce the strength of concrete, with about a 5% reduction in strength for each 1% increase in the volume of air voids.

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Effect of entrained air voids

8 The effects of entrained air on microstructure and transport properties of concrete with up to 11.5% air at different w/c 9 ratios, curing and conditioning regimes were investigated. It was found that air voids disrupt the packing of cement and

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INFLUENCE OF PUMPING ON CHARACTERISTICS OF …

INFLUENCE OF PUMPING ON CHARACTERISTICS OF AIR-VOID SYSTEM OF HIGH-PERFORMANCE CONCRETE The results of an experimental study in which a high-performance air-entrained concrete mixture (water-cement ratio = 0.29; 28-day average compressive strength of 75 MPa) was pumped at the job site horizontally and vertically are presented.

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Concrete Pumping Effects on Entrained Air-Voids

2/7/1994 · Appendices: Concrete Pumping Effects on Entrained Air-Voids Publication URL: Full Document (pdf 1.9 mb) Pumping is a frequently used method of efficiently transporting concrete from the delivery vehicles to the formwork.

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Concrete Pumping Effects on Air-Entrained Voids in Concrete …

Unfortunately, the pumping of air-entrained concrete is known to affect the fresh air content in the fresh concrete. This has caused concern about the durability of concrete in environments where the concrete will experience repeated freezing and thawing cycles.

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Influence of Pumping on Characteristics of Air-Void System of High-Performance Concrete

Table 2 show that the air content measured in the hardened concrete before pumping (4.3 percent) is relatively low. The air-void system, however, can be considered excellent because the specific surface of the air voids is very high (33.6 mm-.1), and the spacing

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Concrete Pumping Effects on Air-Entrained Voids in …

2/7/1994 · Home » Concrete pumping Concrete pumping WA-RD 313.2 Appendices: Concrete Pumping Effects on Entrained Air-Voids Full Document (pdf 1.9 mb) Authors: William Elkey, Donald J. Janssen, Kenneth C. Hover. Originator: Washington State Transportation

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