Author: Daniel Stephen Lane
Publisher:
ISBN:
Category : Pavements, Concrete
Languages : en
Pages : 18
Book Description
Petrographic examinations of specimens from two recently constructed concrete pavements suggested that complete consolidation of the concrete may not have been achieved. Consequently, a quantitative evaluation of the degree of consolidation in these specimens was undertaken. The pavements were of plain, jointed design with dowels for load transfer. Both projects were constructed using slip-form paving machines with spud vibrators. It was found that the entrapped void content was excessive. In both cases, the entrapped void content of the lower half of the pavement was higher than the upper half. This situation apparently occurred because the vibrators were set to ride above the preplaced dowel assemblages. In one pavement the consolidation of the upper half was adequate, but the entrapped void content of the upper half of the other pavement was also found to be excessive. The following recommendations are made: (1) During preplacement conferences and actual construction, emphasize the importance of adequate consolidation of concrete throughout the pavement, especially in the vicinity of dowel assemblages. (2) Consider alternative methods of dowel placement. Pavers with dowel bar inserters are available. (3) Investigate methods to evaluate and monitor consolidation during construction. Nuclear gauges are used for this purpose in some states although not all applications have been successful. Ultrasonic techniques show promise for this application.
Evaluation of Consolidation in Concrete Pavements
Author: Daniel Stephen Lane
Publisher:
ISBN:
Category : Pavements, Concrete
Languages : en
Pages : 18
Book Description
Petrographic examinations of specimens from two recently constructed concrete pavements suggested that complete consolidation of the concrete may not have been achieved. Consequently, a quantitative evaluation of the degree of consolidation in these specimens was undertaken. The pavements were of plain, jointed design with dowels for load transfer. Both projects were constructed using slip-form paving machines with spud vibrators. It was found that the entrapped void content was excessive. In both cases, the entrapped void content of the lower half of the pavement was higher than the upper half. This situation apparently occurred because the vibrators were set to ride above the preplaced dowel assemblages. In one pavement the consolidation of the upper half was adequate, but the entrapped void content of the upper half of the other pavement was also found to be excessive. The following recommendations are made: (1) During preplacement conferences and actual construction, emphasize the importance of adequate consolidation of concrete throughout the pavement, especially in the vicinity of dowel assemblages. (2) Consider alternative methods of dowel placement. Pavers with dowel bar inserters are available. (3) Investigate methods to evaluate and monitor consolidation during construction. Nuclear gauges are used for this purpose in some states although not all applications have been successful. Ultrasonic techniques show promise for this application.
Publisher:
ISBN:
Category : Pavements, Concrete
Languages : en
Pages : 18
Book Description
Petrographic examinations of specimens from two recently constructed concrete pavements suggested that complete consolidation of the concrete may not have been achieved. Consequently, a quantitative evaluation of the degree of consolidation in these specimens was undertaken. The pavements were of plain, jointed design with dowels for load transfer. Both projects were constructed using slip-form paving machines with spud vibrators. It was found that the entrapped void content was excessive. In both cases, the entrapped void content of the lower half of the pavement was higher than the upper half. This situation apparently occurred because the vibrators were set to ride above the preplaced dowel assemblages. In one pavement the consolidation of the upper half was adequate, but the entrapped void content of the upper half of the other pavement was also found to be excessive. The following recommendations are made: (1) During preplacement conferences and actual construction, emphasize the importance of adequate consolidation of concrete throughout the pavement, especially in the vicinity of dowel assemblages. (2) Consider alternative methods of dowel placement. Pavers with dowel bar inserters are available. (3) Investigate methods to evaluate and monitor consolidation during construction. Nuclear gauges are used for this purpose in some states although not all applications have been successful. Ultrasonic techniques show promise for this application.
Handbook on Nondestructive Testing of Concrete
Author: V.M. Malhotra
Publisher: CRC Press
ISBN: 1420040057
Category : Technology & Engineering
Languages : en
Pages : 387
Book Description
Civil and structural engineering consultants engaged in quality control or investigations of hardened concrete need a comprehensive resource that explains the methods of determining strength and other performance characteristics. Handbook on Nondestructive Testing of Concrete, Second Edition answers this demand by providing a thorough analys
Publisher: CRC Press
ISBN: 1420040057
Category : Technology & Engineering
Languages : en
Pages : 387
Book Description
Civil and structural engineering consultants engaged in quality control or investigations of hardened concrete need a comprehensive resource that explains the methods of determining strength and other performance characteristics. Handbook on Nondestructive Testing of Concrete, Second Edition answers this demand by providing a thorough analys
Initial Laboratory Studies of the Nondestructive Evaluation of Concrete Consolidation Using a Pulsed Ultrasonic Interferometer
Author:
Publisher:
ISBN:
Category : Nondestructive testing
Languages : en
Pages : 38
Book Description
The objectives of this study were (1) to study the feasibility of using a pulsed, swept-frequency ultrasonic interferometer in the nondestructive evaluation of the degree of concrete consolidation and (2) to find a correlation between the degree of consolidation and the ultrasonic velocity calculated from the phase slope. The system developed incorporated a pulsed ultrasonic interferometer, an oscilloscope, and a PC for automatic data logging and processing. Typical results from the ultrasonic monitoring of consolidation in fresh concrete at an early age are presented, and a correlation between the degree of consolidation and the ultrasonic velocity calculated from the phase slope is shown. The system developed was able to make ultrasonic velocity, amplitude, waveform, and frequency measurements on plastic and hardened concrete. The results suggest that void size may affect ultrasonic travel in a manner that can be differentiated by the equipment. Variations in paste development that affect the measurement of velocity abate about 12 hr after mixing. Thereafter, the system can be an accurate approach for the nondestructive evaluation of the degree of concrete consolidation. The authors recommend additional study to further refine the capabilities of the system.
Publisher:
ISBN:
Category : Nondestructive testing
Languages : en
Pages : 38
Book Description
The objectives of this study were (1) to study the feasibility of using a pulsed, swept-frequency ultrasonic interferometer in the nondestructive evaluation of the degree of concrete consolidation and (2) to find a correlation between the degree of consolidation and the ultrasonic velocity calculated from the phase slope. The system developed incorporated a pulsed ultrasonic interferometer, an oscilloscope, and a PC for automatic data logging and processing. Typical results from the ultrasonic monitoring of consolidation in fresh concrete at an early age are presented, and a correlation between the degree of consolidation and the ultrasonic velocity calculated from the phase slope is shown. The system developed was able to make ultrasonic velocity, amplitude, waveform, and frequency measurements on plastic and hardened concrete. The results suggest that void size may affect ultrasonic travel in a manner that can be differentiated by the equipment. Variations in paste development that affect the measurement of velocity abate about 12 hr after mixing. Thereafter, the system can be an accurate approach for the nondestructive evaluation of the degree of concrete consolidation. The authors recommend additional study to further refine the capabilities of the system.
Relationship of Consolidation to Performance of Concrete Pavements
Author: David Whiting
Publisher:
ISBN:
Category : Concrete
Languages : en
Pages : 152
Book Description
A study was made of the influence of consolidation on properties of portland cement concrete. A model acceptance sampling plan for concrete consolidation is proposed. The plan is of the inspection by variables type and requires a sample size of eight per lot. The plan provides for buyer's and seller's risks of 5 percent. The plan was field tested in Idaho and Iowa. Field testing indicated that monitoring concrete pavement consolidation is practical and economically feasible.
Publisher:
ISBN:
Category : Concrete
Languages : en
Pages : 152
Book Description
A study was made of the influence of consolidation on properties of portland cement concrete. A model acceptance sampling plan for concrete consolidation is proposed. The plan is of the inspection by variables type and requires a sample size of eight per lot. The plan provides for buyer's and seller's risks of 5 percent. The plan was field tested in Idaho and Iowa. Field testing indicated that monitoring concrete pavement consolidation is practical and economically feasible.
Report No. FHWA-RD.
Author: United States. Federal Highway Administration. Offices of Research and Development
Publisher:
ISBN:
Category :
Languages : en
Pages : 112
Book Description
Publisher:
ISBN:
Category :
Languages : en
Pages : 112
Book Description
ACI Materials Journal
Author:
Publisher:
ISBN:
Category : Concrete
Languages : en
Pages : 692
Book Description
Publisher:
ISBN:
Category : Concrete
Languages : en
Pages : 692
Book Description
Improved materials utilization and durability
Author: United States. Federal Highway Administration
Publisher:
ISBN:
Category : Highway engineering
Languages : en
Pages : 198
Book Description
Publisher:
ISBN:
Category : Highway engineering
Languages : en
Pages : 198
Book Description
Conference - Canadian Society for Civil Engineering
Author: Canadian Society for Civil Engineering. Conference
Publisher:
ISBN:
Category : Civil engineering
Languages : en
Pages : 1008
Book Description
Publisher:
ISBN:
Category : Civil engineering
Languages : en
Pages : 1008
Book Description
Quality Control of Concrete On-site
Author: David Whiting
Publisher: National Research Council
ISBN:
Category : Technology & Engineering
Languages : en
Pages : 68
Book Description
This implementation package provides descriptions and evaluations of conventional concrete testing and new concrete testing. New test descriptions and evaluations include 1) microwave oven drying, 2) temperature-matched curing, 3) maturity, 4) density, and 5) pulse-velocity.
Publisher: National Research Council
ISBN:
Category : Technology & Engineering
Languages : en
Pages : 68
Book Description
This implementation package provides descriptions and evaluations of conventional concrete testing and new concrete testing. New test descriptions and evaluations include 1) microwave oven drying, 2) temperature-matched curing, 3) maturity, 4) density, and 5) pulse-velocity.
Synthesis of Highway Practice
Author: National Cooperative Highway Research Program
Publisher:
ISBN:
Category : Highway engineering
Languages : en
Pages : 540
Book Description
Publisher:
ISBN:
Category : Highway engineering
Languages : en
Pages : 540
Book Description