Investigating Effects of Concrete Handling on Air …

1/9/1995 · Study evaluates air loss in fresh concrete due to pumping and other handling methods. A 1994 study examined the effects of concrete handling methods on normal air-entrained concrete. Concrete for a large parking lot and driveway project was placed by pump, crane and bucket, truck-mounted conveyer, and directly from the chutes of ready mix

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Volume 19/Number 1 Control of Air Content in Concrete April 1998

Effects of Concrete Ingredients on Air Content Material Effects Guidance Cement Alkali content Air content increases Changes in alkali Pumping Reduction in air content Use loop in descending ranges from 2 to 3%. pump line. Keep the pumping pressure as

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Investigation into the Effects of Materials and Mixing …

1/11/2006 · The air void analyzer (AVA) was used to investigate the effects of concrete materials and mixing procedures on air void characteristics of fresh concrete. Twenty-seven batches of concrete were made with three mix proportions (with and without Class C fly ash or

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Concrete Pumping Effects on Entrained Air-Voids

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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Research - Concrete Pumping Effects on Entrained Air …

2/7/1994 · Unfortunately, pumping concrete can affect the air content of a concrete mix. This has caused concern about the possible loss of resistance of the concrete to freezing and thawing. The actual effect of pumping on the air content measured for the concrete is not

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Concrete Pumping Effects on Air-Entrained Voids in …

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 system. The laboratory tests conducted show a significant amount of air volume was lost in the fresh concrete as a result of pumping.

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Investigating Effects of Concrete Handling on Air …

1/9/1995 · Study evaluates air loss in fresh concrete due to pumping and other handling methods A 1994 study examined the effects of concrete handling methods on normal air-entrained concrete. Concrete for a large parking lot and driveway project was placed by pump, crane and bucket, truck-mounted conveyer, and directly from the chutes of ready mix trucks.

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Concrete Pumping Effects on Air-Entrained Voids in Concrete …

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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Concrete pumping and its effect on the air void system | …

5/7/2018 · The particular effect of pumping on changes in the concrete air void system has been investigated in the past [5,6,7,8,9,10]. The general belief within the North American concrete industry is that pumping reduces air content by two or three percent [].

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concrete pumping | CZBY CONCRETE PUMP PARTS

29/5/2015 · "Effects of Pumping Air Entrained Concrete," Washington Aggregates and Concrete Association, March 20, 1991, 12 pp. Dyer, R.M., "An Investigation of Concrete Pumping Pressure and the Effects on the Air Void System of Concrete," Master's Thesis

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concrete pumping | CZBY CONCRETE PUMP PARTS

29/5/2015 · Dyer, R.M., "An Investigation of Concrete Pumping Pressure and the Effects on the Air Void System of Concrete," Master's Thesis, Department of Civil Engineering, University of Washington, Seattle, Washington, 1991. Personal correspondence with authors and photographs, July 13, 1992 (copies available on request).

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Concrete Slab Surface Defects: Causes, Prevention, Repair

Fogging the air above the concrete and erecting windshades lessen the risk of plastic-shrinkage cracking. Concrete has a coefficient of thermal expansion and contraction of about 10 x 10-6 per C (5.5 x 10-6 per F). Concrete placed dur-ing hot midday night. A

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CONCRETE PUMPING EFFECTS ON ENTRAINED AIR …

Unfortunately, pumping concrete can affect the air content of a concrete mix. This has caused concern about the possible loss of resistance of the concrete to freezing and thawing. The actual effect of pumping on the air content measured for the concrete is not

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Effect of Accelerating Admixture on Properties of Concrete

extreme cases, effects of cold weather may make the concrete an absolutely useless friable mass. On the other hand, if the concrete is sufficiently hardened when freezing conditions are likely to prevail, there will not be much harm to structural integrity of

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Supplier of Concrete Admixtures and Surface Products - Factors Which May Influence Air …

and maintain satisfactory concrete temperatures. III. Effects of Construction Practices Pumping Concrete – May result in air content reductions of 2%-3% at the discharge end of the pump boom. Higher air losses usually are the result of boom configuration

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Loss of Air Content in Pumped Concrete — What, why, & …

As the slug of concrete slides down the pipe, it develops a vacuum on the upper end that greatly expands the size of the air bubbles, and when the concrete hits an elbow in the boom or a horizontal surface, the bubbles collapse. The effect of this impact can be demonstrated by dropping concrete …

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Concrete Pumping Effects on Air-Entrained Voids in …

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 system. The laboratory tests conducted show a significant amount of air volume was lost in the fresh concrete as a result of pumping.

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Examination of Air Entrainment Stability Factors of Pumped Concrete

IMPLEMENTATION STATEMENT 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

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Experimental investigation of photocatalytic effects of …

Experimental investigation of photocatalytic effects of concrete in air purification adopting entire concrete waste reuse model Journal article Xu, Y, Chen, W, Jin, R, …

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Materials | Free Full-Text | Experimental Investigation of …

For real pumping experiments with SCC, effects such as the compressibility of real concrete by entrapped air and time-dependent rheological effects have to be considered, as well. It was clearly noticeable that f p and thus the experimentally determined values were markedly lower than those resulting from the rheological data f r .

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