Vibration Study for Consolidation of Portland Cement Concrete PDF Download
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Author: Shane Tymkowicz
Publisher:
ISBN:
Category : Pavements, Concrete
Languages : en
Pages : 108
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Book Description
The Iowa Department of Transportation has discovered an increase in the occurrence of excessively vibrated portland cement concrete (PCC) pavements. The overconsolidation of PCC pavements has been observed in several projects across the state. Overconsolidation is also believed to be a factor in acceleration of premature deterioration of at least two pavement projects in Iowa. To address the problem, a research project in 1995 documented the vibratory practices of PCC slipform paving in Iowa in order to determine the effect of vibration on consolidation and air content of pavement. Paver speed, vibrator frequency, and air content relative to the location of the vibrator were studied. The study concluded that the Iowa Department of Transportation specification of 5,000 to 8,000 vibrations per minute (vpm) for slipform pavers is effective for normal paver speeds on the three projects that were examined. Excessive vibration was clearly identified on one project where a vibrator frequency of 12,000 vpm was discovered. When the paver speed was reduced to half the normal speed, hard air contents indicate that excessive vibration was beginning to occur in the localized area immediately surrounding the vibrator at a frequency of 8,000 vpm. The study also indicates that the radius of influence of the vibrators is smaller than has been claimed.
Author: Shane Tymkowicz
Publisher:
ISBN:
Category : Pavements, Concrete
Languages : en
Pages : 108
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Book Description
The Iowa Department of Transportation has discovered an increase in the occurrence of excessively vibrated portland cement concrete (PCC) pavements. The overconsolidation of PCC pavements has been observed in several projects across the state. Overconsolidation is also believed to be a factor in acceleration of premature deterioration of at least two pavement projects in Iowa. To address the problem, a research project in 1995 documented the vibratory practices of PCC slipform paving in Iowa in order to determine the effect of vibration on consolidation and air content of pavement. Paver speed, vibrator frequency, and air content relative to the location of the vibrator were studied. The study concluded that the Iowa Department of Transportation specification of 5,000 to 8,000 vibrations per minute (vpm) for slipform pavers is effective for normal paver speeds on the three projects that were examined. Excessive vibration was clearly identified on one project where a vibrator frequency of 12,000 vpm was discovered. When the paver speed was reduced to half the normal speed, hard air contents indicate that excessive vibration was beginning to occur in the localized area immediately surrounding the vibrator at a frequency of 8,000 vpm. The study also indicates that the radius of influence of the vibrators is smaller than has been claimed.
Author:
Publisher:
ISBN:
Category : Concrete
Languages : en
Pages : 230
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Book Description
This study evaluated the impacts of construction on the air content and air-void system structure of Portland cement concrete pavements. The primary intent was to quantify the air content of fresh concrete before and after it has gone through the slipform paver. The air-void system parameters of hardened concrete were then assessed using cast and extracted core specimens. The results of the air content testing on fresh concrete and the concrete cylinder specimens cast in the field suggested that there is some loss of air as the concrete passes through the paver. Laboratory testing performed on cores extracted from the pavement did not provide any conclusive evidence that entrained air is lost during the slipform paving process. In fact, many of the extracted cores had measured air content values that were much higher than the specification requirement. If excessive, this could result in increased permeability and low-strength related issues. Although a rigorous statistical analysis was not performed, the results suggest that the air content testing on fresh concrete is not capturing the true air content of the concrete placed with a slipform paver. The fresh concrete air content is generally lower than the air content measured in the cores.
Author:
Publisher: RILEM Publications
ISBN: 2351580982
Category : Cement
Languages : en
Pages : 307
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Book Description
Author: Mohamad Nagi
Publisher: Transportation Research Board
ISBN: 0309098890
Category : Air-entrained concrete
Languages : en
Pages : 60
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Book Description
"This report presents a recommended procedure for evaluating air-entraining admixtures used in highway concrete. The procedure involves the testing of non-air-entrained concrete and concrete containing the air-entraining admixture under simulated field conditions. Criteria are proposed for acceptance of admixtures for use in either highway pavements or structures. The recommended procedure and acceptance criteria will guide materials engineers in evaluating and selecting air-entraining admixtures that should contribute to appropriate freeze-thaw durability and thus to good performance and long service life. The content of the report will be of immediate interest to materials engineers, researchers, and others concerned with the design of concrete mixtures for use in highway pavements and structures."--taken from Foreword, page [v].
Author: Edward G. Nawy
Publisher: John Wiley & Sons
ISBN: 9780471385554
Category : Technology & Engineering
Languages : en
Pages : 468
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Book Description
High performance concrete is a key element in virtually all-large construction projects, from tall office and residential buildings to bridges, tunnels and roadways. The fully updated Second Edition helps professionals to understand the performance capabilities of these construction materials when selecting the type of concrete to use for particular projects. The author is one of the worlds acknowledged experts on high performance concrete.
Author:
Publisher:
ISBN:
Category : Concrete
Languages : en
Pages : 138
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Book Description
Author:
Publisher:
ISBN:
Category : Roads
Languages : en
Pages : 840
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Author:
Publisher:
ISBN:
Category : Business & Economics
Languages : en
Pages : 240
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Book Description
Author: Joseph F. Lamond
Publisher: ASTM International
ISBN: 0803133677
Category : Technology & Engineering
Languages : en
Pages : 661
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Author: United States. Federal Highway Administration
Publisher:
ISBN:
Category : Highway research
Languages : en
Pages : 958
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Book Description
