research concrete pumping effects on entrained airvoids Related Information

Effect of entrained air voids

30 entrained air voids depend on many factors, including the type and amount of air-entraining agent, materials and mix 31 composition, mixing and placing techniques. These issues and concepts relating to freeze-thaw damage and the 32 . beneficial effects of air entrainment …

Influence of Pumping on Characteristics of Air-Void System

30 TRANSPORTATION RESEARCH RECORD 1478 Influence of Pumping on Characteristics of Air-Void System of High-Performance Concrete R. PLEAU, M. PIGEON, A. LAMONTAGNE, AND M. LESSARD The results of an experimental study in which a high-performance air­ entrained concrete·mixture (water-cement ratio= 0.29; 28-day average

Air entrainment and its effects in concrete • Aggregate

Jul 12, 2010 · Uses and effects of air entrainment. Air entrainment is the process where many small air bubbles are distibuted into concrete and become part of the matrix that binds the aggregate together in the hardened concrete. These air bubbles are dispersed throughout the hardened cement paste but are not, by definition, part of the paste (Dolch 1984).

Magazine of Concrete Research - ICE Virtual Library

Nov 04, 2016 · The purpose of this work was to explore the effect of sodium salts on the air-void structure in air-entrained concrete, and to observe the morphology of the air voids in the presence of sodium sulfate (Na 2 SO 4) and sodium nitrite (NaNO 2) as well as the use of sodium abietate.The foam index test was used in analysing the foam stability of sodium abietate, microscopic determinations of …

(PDF) EFFECT OF AIR VOIDS IN HIGH STRENGTH CONCRETE

entraining admixtures is not necessary or desirable in high such usually parameter is just to check and to compare the effect of air voids in Cement and Concrete Research 33 (2003) 155

Influence of Pumping on Characteristics of Air-Void System

30 TRANSPORTATION RESEARCH RECORD 1478 Influence of Pumping on Characteristics of Air-Void System of High-Performance Concrete R. PLEAU, M. PIGEON, A. LAMONTAGNE, AND M. LESSARD The results of an experimental study in which a high-performance air­ entrained concrete·mixture (water-cement ratio= 0.29; 28-day average

Impact of Concrete Placing Method on Air Content, Air-Void

Jan 01, 1996 · Concrete Pumping Effects on Entrained Air Voids. Final Report, Research Project T9233 Task 21, for the Washington State Transportation Commission, Washington State Transportation Center, University of Washington, Seattle, June 1994, 97 pp. Google Scholar

Review of Literature on Air-Entrained Concrete

or to voids within particles of aggregate. Air voids are almost invariably larger than 2 JL in diameter. The term includes both 'entrapped' and 'entrained' air voids . . . " (e) Air Content, A___:The proportional volume of air voids. in concrete expressed as a percentage of the volume of the hardened con­ crete.

Entrained Air: Now You See It, Now You Don't | American

Jul 26, 2018 · Entrained Air: Now You See It, Now You Don't. Thursday, July 26, 2018. Exciting new research for the concrete pumping industry finds air void loss after pumping to be a temporary condition. Although concrete pumps place more than 60 percent of ready mixed concrete in the U.S., the method's prevalence hasn't inoculated it against criticism

INFLUENCE OF PUMPING ON CHARACTERISTICS OF AIR-VOID SYSTEM

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.

Controlling Air Content in Concrete That is Being Pumped

Joint Transportation Research Program JTRP FHWA/IN/JTRP-98/11 FinalReport ControllingAirContentinConcreteThatisBeing Pumped,ASynthesisStudy CharlesF.Scholer

Concrete Pumping Effects on Entrained Air-Voids

Jul 02, 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 consistent; in some cases air content has increased, while in others it has decreased.

Appendices: Concrete Pumping Effects on Entrained Air-Voids

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

Concrete pumping and its effect on the air void system

The full scale field measurements using Super Air Meter were also conducted on fresh air-entrained concrete to study the effects of pumping [16]. A good agreement was found between SAM test

Effect of entrained air voids on the microstructure and

Oct 01, 2011 · 1. Introduction. A typical concrete contains around 1-2% vol. of air voids that are inadvertently entrapped because of incomplete compaction. Air voids may also be deliberately incorporated by means of a suitable surfactant, i.e. an air entraining admixture.

Air entrainment in fresh concrete and its effects on

Mar 08, 2021 · SF can influence the entrained air voids in concrete. Because of the high surface area of SF, it was reported that with the addition of condensed silica fume (CSF), the dosage of AEA to obtain required air content increased,, . In the presence of a high amount of CSF in concrete, it is difficult to achieve 5% air content .

The effects of pumping on the air content and void

Dec 01, 2019 · Pleau et al concluded that impact destroys mainly larger air voids, whereas the number of smaller air voids (<300 μm in diameter) is less affected. Consequently, the mix designer should take into account the effects which pumping and placement will have on the air voids system of the mix after it has been discharged from the nozzle.

I. RESEARCH PROJECT TITLE: Best Practices for Concrete

affect the entrained air voids before and after pumping. This project has the objectives of determining how changes in different materials allowed in low-cracking high-performance concrete (LC-HPC) mixtures affect the concrete rheology and air systems. The project will also go to concrete field placements with pumping to determine

Effect of Air Entrained Concrete on Strength of Concrete

1. Effect of Air Entrainment on Concrete Compressive Strength Air entraining admixture is usually introduced when it is desired to increase concrete workability without affecting much reduction in compressive strength. It is claimed that, the place-ability of an air entrained concrete having 7.5 cm slump is better than a non-air entrained

Effect of air entrainment on shrinkage of blended cements

property research with shrinkage and concrete transport proper- interfacial transition zone around air voids. Therefore, a certain effect of air entrainment on shrinkage strains of concretes