Evaluation of Dowel Bar Retrofits for Local Road Pavements PDF Download
Are you looking for read ebook online? Search for your book and save it on your Kindle device, PC, phones or tablets. Download Evaluation of Dowel Bar Retrofits for Local Road Pavements PDF full book. Access full book title Evaluation of Dowel Bar Retrofits for Local Road Pavements by . Download full books in PDF and EPUB format.
Author:
Publisher:
ISBN:
Category : Dowels
Languages : en
Pages : 52
Get Book Here
Book Description
As truck traffic on Iowa secondary roads has increased, engineers have moved to concrete pavements of greater depths. Early designs included thickened edge pavements and depths of seven inches or greater. The designs typically did not have load transfer devices installed in the transverse joints and relied on aggregate interlock for this purpose. In some cases, aggregate interlock was not adequate to deal with the soils and traffic conditions and faulting of the joints has begun to appear. Engineers are now faced with the need to install or retrofit load transfer in the joints to preserve the pavements. Questions associated with this decision range from the type of dowel material to dowel diameter, spacing, number of bars, placement method, and construction techniques to be used to assure reduction or elimination of faulting. Buena Vista County constructed a dowel bar retrofit project on one mile of road. The plan called for addition of the dowels (2, 3, or 4) in the outer wheel path only and surface grinding in lieu of asphalt overlay. The project included the application of elliptical-and round-shaped dowels in a rehabilitation project. Dowel material types included conventional epoxy-coated steel and fiber-reinforced polymer. This work involved the determination of relative costs in materials to be used in this type of work and performance of fiber-reinforced polymer (FRP) and elliptical-shaped steel dowels in the retrofit work. The results indicate good performance from each of the bar configurations and use the results of ride and deflection testing over the research period to project the benefits that can be gained from each configuration vs. the anticipated construction costs. The reader is cautioned that this project could not relate the number of dowels required to the level of anticipated truck traffic for other roads that might be considered.
Author:
Publisher:
ISBN:
Category : Dowels
Languages : en
Pages : 52
Get Book Here
Book Description
As truck traffic on Iowa secondary roads has increased, engineers have moved to concrete pavements of greater depths. Early designs included thickened edge pavements and depths of seven inches or greater. The designs typically did not have load transfer devices installed in the transverse joints and relied on aggregate interlock for this purpose. In some cases, aggregate interlock was not adequate to deal with the soils and traffic conditions and faulting of the joints has begun to appear. Engineers are now faced with the need to install or retrofit load transfer in the joints to preserve the pavements. Questions associated with this decision range from the type of dowel material to dowel diameter, spacing, number of bars, placement method, and construction techniques to be used to assure reduction or elimination of faulting. Buena Vista County constructed a dowel bar retrofit project on one mile of road. The plan called for addition of the dowels (2, 3, or 4) in the outer wheel path only and surface grinding in lieu of asphalt overlay. The project included the application of elliptical-and round-shaped dowels in a rehabilitation project. Dowel material types included conventional epoxy-coated steel and fiber-reinforced polymer. This work involved the determination of relative costs in materials to be used in this type of work and performance of fiber-reinforced polymer (FRP) and elliptical-shaped steel dowels in the retrofit work. The results indicate good performance from each of the bar configurations and use the results of ride and deflection testing over the research period to project the benefits that can be gained from each configuration vs. the anticipated construction costs. The reader is cautioned that this project could not relate the number of dowels required to the level of anticipated truck traffic for other roads that might be considered.
Author: Linda M. Pierce
Publisher:
ISBN:
Category : Dowels
Languages : en
Pages : 534
Get Book Here
Book Description
Author: Tom Pyle
Publisher:
ISBN:
Category : Dowels
Languages : en
Pages : 81
Get Book Here
Book Description
Author: Nicholas A. Popehn
Publisher:
ISBN:
Category : Dowels
Languages : en
Pages : 108
Get Book Here
Book Description
Effective load transfer across Portland cement concrete pavement joints significantly decreases pavement deterioration. Areas of concern with using dowel bars include high costs, due to the labor-intensive procedure of retrofitting, and corrosion associated with standard mild steel epoxy-coated dowels. This research addresses these problems by evaluating four dowel bar details tested in an accelerated manner. Retrofit testing was performed using mild-steel epoxy coated dowels and fiber reinforced polymer (FRP) dowels. The details tested provide comparisons among dowel bar materials, depth of placement, number of dowels used, and dowel diameter. Verification testing of previously tested details is also presented.
Author: Joe R. Wilson
Publisher:
ISBN:
Category : Pavements, Asphalt
Languages : en
Pages : 56
Get Book Here
Book Description
Author: Irene K. Battaglia
Publisher:
ISBN:
Category : Dowels
Languages : en
Pages : 52
Get Book Here
Book Description
Author: Farshad Fallah
Publisher:
ISBN:
Category : Dowels
Languages : en
Pages : 37
Get Book Here
Book Description
Dowel Bar Inserters (DBI) are automated mechanical equipment that position dowel bars in Portland Cement Concrete (PCC) after concrete is placed. Compared to the alternative approach, which is using dowel baskets, DBIs offer advantages in cost and the speed of construction. However, as dowel bars are not anchored to the subgrade similar to dowel baskets, there is a concern about the quality of dowel placement using this equipment. Improper placement of dowel bars can lead to reduced load transfer between slabs, which results in pavement distresses such as faulting and spalling at joints. To determine the accuracy of dowel placement by DBI, the Nebraska Department of Roads has used an MIT Scan-2 device to scan the joints in projects where a DBI was used. This device uses a nondestructive magnetic imaging technique to capture the position of dowel bars inside the pavement. The aim of this project is to analyze the MIT Scan-2 data of the joints constructed using a DBI, and to compare them with the corresponding field performance data. This will allow us to judge if DBU is a reliable alternative for dowel placement, and to improve Nebraska's current specifications for dowel placement tolerances (page viii).--
Author: Jan Olek
Publisher: Purdue University Press
ISBN: 9781622602124
Category :
Languages : en
Pages : 288
Get Book Here
Book Description
When dealing with the issue of repair of concrete pavement repair using dowel bar retrofit technique, it is very desirable for the repair material to have high fluidity that can ensure good compaction and facilitate flow to tight spaces, preferably without the use of a vibrator. The focus of this project was on identifying critical properties that control long-term performance of repair concrete, especially rapid-setting materials extended using pea gravel (maximum size aggregate 9.5 mm). In the first phase of this project, four commercial rapid-setting materials (CRSMs) were selected and development of mixture proportions in terms of optimum pea gravel content and water content was performed. Optimized mixtures were further evaluated at three different initial temperature conditions. The properties evaluated included workability, setting time, rate of compressive strength developed, slant shear bond strength, freeze-thaw resistance, air-void system characteristics of hardened concrete, drying shrinkage and cracking potential. It was observed that some of the CRSMs evaluated did not meet requirements of ASTM C 928. All, except one, CRSMs tested exhibited low resistance to freezing and thawing but all had high resistance to cracking. In the second phase of the project, rapid-setting self-consolidating concrete (RSSCC) was developed using ternary blend of cementitious materials, high-range water reducer (HRWR) and accelerators. Slump flow, visual stability index (VSI), compressive strength at various ages and the power consumption values for the mortar mixer indicated that a five minutes mixing sequence involving a 2-step addition of HRWR produces stable RSSCC mixture. The results of various tests carried out indicate that it is possible to develop a small aggregate size-based self-consolidating repair concrete that achieves a compressive strength of 19 MPa at the end of 6 hrs, has good bond characteristics and has excellent freezing and thawing durability (DF>90%).
Author: Iowa. Department of Transportation. Bureau of Research and Technology
Publisher:
ISBN:
Category : Intelligent transportation systems
Languages : en
Pages : 164
Get Book Here
Book Description
Author: Sara Jennifer Somsky
Publisher:
ISBN:
Category :
Languages : en
Pages : 302
Get Book Here
Book Description
In jointed concrete pavements, dowel bars are typically used to transfer loads between adjacent slabs. These dowels are typically made of steel and are spaced 12 inches on center for the full length of a transverse joint. The objective of this research was to evaluate the impact of the number of dowel bars and dowel location on pavement performance and joint performance. Consequently, four dowel arrangements were evaluated: 1) zero dowels, 2) three dowels in the outside wheel path, 3) four dowels in the outside wheel path, and 4) full basket of dowels (twelve). In addition, two test sites were prepared with two different subgrades, one with a compacted soil subgrade (Rural site) another with a built up asphalt surface treatment subgrade (Urban site). Evaluations of the test sections were performed biannually (early fall or late summer and early spring) over a five-year testing period. In addition, a soil investigation was performed using in-situ soil classification from soil borings and consultation of US Department of Agriculture soil survey. Biannual evaluation of both the Urban and Rural sites consisted of: 1) visual distress surveys, 2) joint opening measurements, 3) joint faulting measurements, and 4) deflection measurements using an Iowa DOT (Department of Transportation) Road Rater. Analysis of the biannual testing indicated that the stiffness of a subgrade magnifies the effect of dowel arrangement on a pavement. It was recommended for pavements with a weak subgrade (dynamic k-values less than 200) to use the standard (full) dowel compliment. For pavements with a strong/stiff subgrade (dynamic k-values greater than 220), three or four dowels in the outside wheel path will suffice. Additional investigation is needed to recommend a dowel bar arrangement for moderately weak to moderately strong subgrades, possibly with dowels in the inside wheel path.
