Longitudinal Joint Construction Research Articles

Flexible pavement longitudinal joint quality evaluation using non-destructive testing

Longitudinal joint construction quality is critical to the life of flexible pavements. Maintaining deteriorated longitudinal joints has become a challenge for many highway agencies. Improving the joint's quality through better compaction during construction can help achieve flexible pavements with longer service lives and less maintenance. Current quality control (QC) and quality assurance (QA) plans provide limited coverage. Consequently, the risk of missing areas with poor joint compaction is significant. A density profiling system (DPS) is a non-destructive alternative to conventional destructive evaluation methods. It can provide quick and continuous real-time coverage of the compaction during construction in dielectrics. The paper presents several case studies comparing various types of longitudinal joints and demonstrating the use of DPS to evaluate the joint's compaction quality. The paper shows that dielectric measurements can provide valuable insight into the ability of various construction techniques to achieve adequate levels of compaction at the longitudinal joint. The paper proposes a dielectric-based longitudinal joint quality index (LJQI) to evaluate the relative compaction of the joint during construction. It also shows that adopting DPS for assessing the compaction of longitudinal joints can minimize the risk of agencies accepting poorly constructed joints, identify locations of poor quality during construction, and achieve better-performing flexible pavements.

Cover Picture: Geomechanics and Tunnelling 2/2024

AbstractLining stress controllers (LSC) have been developed as special supporting measure for tunnelling in zones with stress‐induced failure involving large ground volumes and large deformations. The shotcrete lining is divided into several segments by longitudinal construction joints. The purpose of this segmentation is to absorb large deformations occurring during tunnel driving in weak ground. LSC elements are installed into these deformation joints. These elements have a defined workload during compression so the primary lining is not damaged (Source: DSI Underground).

Deep learning-based detection of tie bars in concrete pavement using ground penetrating radar

ABSTRACT Detection of the tie bars in concrete pavement has been a challenging task. To address the purpose, ground penetrating radar (GPR) was used to acquire a large amount of image data along the longitudinal construction joints of plain concrete pavement in the field. The GPR image data was filtered to construct the dataset, containing 2185 tie bar reflected waves in 670 GPR images. Then, the YOLO series models, as the deep learning algorithms applied in inspecting the tie bars from GPR images, were well trained with the GPR training and validation sets. The comprehensive detection accuracy of the YOLOv4 model outperforms the YOLOv3, YOLOv3-tiny, and YOLOv4-tiny models in the test set. The mAP@0.5 value of the YOLOv4 model can reach 99.74%. All the signatures of tie bars in the testing GPR images, no matter whether they are incomplete, compressed, blurry with missing signal, or strong background noise, can be correctly and completely anchored using the bounding box based on the YOLOv4 model. Meanwhile, the detection speed of the YOLOv4 model for GPR data video is 50.8 frames per second. Therefore, the YOLOv4 model is reliable for automatically detecting the tie bars from GPR data in real-time.

Comparison of Stress Fields near Longitudinal Construction Joints of Tied and Doweled Sections in Portland Cement Concrete Pavements

In Portland cement concrete (PCC) pavements, tie bars are commonly used at longitudinal construction joints (LCJs) to prevent the lanes from separating. Meanwhile, the increase in multiple lanes due to greater traffic volumes has raised concerns about potential longitudinal cracking; this has led to the use of dowel bars instead of tie bars at LCJs. However, there is a paucity of studies focused on the comparison between the behaviors of concrete pavement based on the restrained conditions provided by tie and dowel bars at LCJs. In this study, we investigated the effects of the placement of tie and dowel bars at LCJs on the potential for longitudinal cracking in response to the increase in concrete stress that may occur when the lanes are tied together in PCC pavements. Field testing verified that the variation in concrete strain was more restrained in the case of a tie bar than a dowel bar, whereas it resulted in higher stress in the concrete element in the tie bar section. However, the use of dowel bars caused more movement in the transverse direction at LCJs as compared with tie bars. Thus, our results indicate that using dowel bars reduces the potential for longitudinal cracking; however, it may increase the potential for lane separation.

Quality control/quality assurance testing for longitudinal joint density and segregation of asphalt mixtures

Longitudinal joint quality control/assurance is essential to the successful performance of asphalt pavement and it has received considerable amount of attention in recent years. Five paving projects were selected for sampling and evaluation in Iowa. For each project, joint quality is compared with regard to the “center” of the pavement mat (6′ right of joint). Field densities and permeability test were made. Cores were obtained for subsequent lab permeability, density and indirect tensile (IDT) strength testing. Asphalt content and gradations were also obtained to determine the joint segregation.In general, this study found that methods providing the most reliable measurements of joint quality are the AASHTO T166, AASHTO T331 (CoreLok) density tests and the permeability test by Karol-Warner Permeameter. The minimum required joint density for quality control should be around 90.0% and 88.5% of theoretical maximum density based on the AASHTO T166 and AASHTO T331 method respectively. Based on various mix design and longitudinal joint construction methods, the joints show differences in asphalt content and level of segregation. Results of this study indicate that poor quality of longitudinal joint should be a combination of segregation, asphalt content variation and insufficient density.

Interrelationship between Tire Contact Stress and Longitudinal Construction Joint Layout in Pavement

Abstract In reconstruction and rehabilitation expressway projects, there are a series of longitudinal construction joints between old and new semi-rigid bases. As the weak parts in the whole structure, the longitudinal construction joints have a trend to damage earlier than other parts. In this paper, based on a highway project, the finite element method was used to analyze the effect of longitudinal construction joint layout and bond conditions on mechanical response of semi-rigid base pavement under normal loading and heavy loading. Analysis results showed that maximum stress under heavy loading of 50 % larger than normal loading would increase 20 %. Bond condition was another significantly important factor. Under heavy loading, the bond between old parts and new parts need higher adhesion strength. The longitudinal construction joints should be set as far as possible away from the wheelpath. If its position was 50 cm away from the load, maximum stress in the structure will decrease more than 25 %.

Evaluation of Longitudinal Joint Construction Techniques for Asphalt Pavements in Tennessee

Longitudinal joints between lanes of hot-mix asphalt (HMA) pavements are commonly susceptible to moisture damage and other failures. In 2006, the Tennessee Department of Transportation (TDOT) identified longitudinal joint failure as one of the major distresses for local HMA pavements. It was determined necessary to evaluate available practices and technologies to reduce longitudinal joint failure. This paper presents the results from a field project in Tennessee constructed with seven different longitudinal joint construction techniques. These techniques could be divided into three major categories: joint adhesives including an anionic emulsion and a polymerized emulsion commonly used by the TDOT, a hot-applied high-polymer rubber, and a high-polymer emulsion; joint sealers including a polymerized maltene emulsion and a polymerized agricultural oil; and infrared joint heater. Laboratory tests were conducted on the field cores taken from the test sections constructed with these techniques. Based on the different mechanisms of these techniques, the following laboratory tests were employed: air void content, permeability, indirect tensile (IDT) strength, and water absorption tests. Field cores were also scanned with the X-ray computed tomography to investigate the effect of infrared heating on air void distribution. The test results showed general consistency in the joint quality; i.e., the lower the air void content, the lower the permeability and the higher the IDT strength. The infrared heater exhibited the best effectiveness in improving joint quality among all the joint construction techniques used in this study.

Behavior of Tied Multiple-Lane Portland Cement Concrete Pavement

Tie bars are used at longitudinal construction joints (LCJs) in portland cement concrete (PCC) pavement primarily to keep lanes from separating. As more lanes are tied together because of ever-increasing traffic volume, concerns about the potential for longitudinal cracking have led to the use of dowel bars at LCJs. However, a survey of a number of state highway agencies (SHAs) revealed that few of them have guidelines and design standards for the use of dowel bars at LCJs and that no in-depth studies conducted in this area have been identified. The effects of multiple lane ties and dowel bar placements in PCC pavements are analyzed in this paper to provide basic information on whether dowel bars are really needed, and if they are, where they should be placed and what their advantages and disadvantages are. Field testing verified that the longitudinal cracking potential is greater as slab thickness and lane width increase. The effects of multiple lane ties and dowel bar placements at LCJs are evaluated with numerical analysis. Placing dowel bars in lieu of tie bars reduces the longitudinal cracking potential, and the effectiveness of using dowel bars is enhanced when they are applied to thicker and wider pavements. However, the use of dowel bars could result in increased potential for lane separations.

Investigation of Settlement of a Jointed Concrete Pavement

A section of jointed concrete pavement on U.S. 75, which was built from 1982 to 1985, in the Paris District of the Texas Department of Transportation (TxDOT) experienced severe pumping and settlement, even though two types of treatment (full depth repair and polyurethane foam injection) were performed. An extensive field investigation was conducted using ground penetrating radar, falling weight deflectometer, dynamic cone penetrometer, and coring to identify the causes of the continued pumping and settlement problems, and develop an optimal repair strategy. The pavement evaluation included tie bar condition, load transfer efficiency (LTE) at transverse and longitudinal construction joints, and base support conditions. Some of the tie bars failed in shear due to corrosion, which resulted in substantially low LTEs ( <40% ) at longitudinal construction joints. Pumping and settlement problems were more pronounced where the tie bars failed; the resulting large deflections exacerbated the pumping and settlement...

Design of Tie Bars in Portland Cement Concrete Pavement considering Nonlinear Temperature Variations

Tie bar design at longitudinal construction joints in portland cement concrete pavement is based on the so-called subgrade drag theory. According to this theory, the required maximum spacing between tie bars is inversely proportional to the widths of the lanes that are tied together. As the number of lanes increases to accommodate greater traffic demand, tie bar spacing decreases. In a recent IH-10 project in Houston, Texas, the width of pavement lanes tied together was great enough to require 30-cm (1-ft) tie bar spacing. In Texas Department of Transportation design standards for continuously reinforced concrete pavement, the same spacing is required for both tie bars and transverse steel. The use of 30-cm spacing for both tie bars and transverse steel results in a substantial increase in the cost of the project. The subgrade drag theory assumes uniform temperature distribution through the concrete slab depth and no curling effect is incorporated. This assumption needs reconsideration. Field testing was conducted to investigate slab behavior and to develop more rational designs for tie bars and transverse steel. Concrete displacement gauges were installed at the free edge of the concrete slab to measure transverse horizontal as well as vertical displacements. Steel strain gauges were installed at different locations in tie bars. The concrete slab showed curling behavior; the stresses in tie bars clearly demonstrated the effects of curling. Theoretical analysis was conducted, and the results verified the field data. A new design method was proposed for tie bars.

Evaluation of Eight Longitudinal Joint Construction Techniques for Asphalt Pavements in Pennsylvania

Premature deterioration of multilane hot-mix asphalt pavements can occur at the longitudinal joints in the form of cracking and raveling. The National Center for Asphalt Technology initiated a national study that evaluated various longitudinal joint construction techniques in 1992 in an effort to select the technique(s) that improves the performance of longitudinal joints. Test sections were constructed in Michigan, Wisconsin, Colorado, Pennsylvania, and New Jersey. The 6-year performance evaluation of eight different techniques used on a paving project in Pennsylvania in 1995 is provided. In Pennsylvania, longitudinal joint constructed with rubberized joint material gave the best performance, closely followed by the joint made with a cutting wheel. Test sections on which rolling from the hot side 152 mm away from the joint and the New Jersey wedge joint were used also performed reasonably well, with no significant cracking. The remaining four test sections on which the edgerestraining device, joint maker, rolling from the hot side, and rolling from the cold side were used developed cracking at the longitudinal joint to different extents. It has been recommended that the minimum compaction level at the longitudinal joint be specified to ensure its improved performance.

Evaluation of Notched-Wedge Longitudinal Joint Construction

The proper construction of longitudinal joints is critical to the overall performance of a hot-mix asphalt (HMA) pavement. Many times the in-place density at and across the longitudinal joint is substantially lower than the density of the remainder of the HMA surface. This low in-place density increases the potential for cracking and raveling to develop along the joint. Research has shown that the use of the notched-wedge joint has the potential to increase the density at the longitudinal joint, which should result in a longer-lasting pavement. The notched-wedge joint construction technique was compared with conventional longitudinal joint construction techniques on projects in five states (Colorado, Indiana, Alabama, Wisconsin, and Maryland). The evaluation consisted of comparing the in-place densities obtained through pavement cores at five locations across the longitudinal joint of the pavement: at the centerline and at 150 mm (6 in.) and 450 mm (18 in.) on either side of the centerline. The results of the study indicate that the notched-wedge joint can be successfully used to increase the in-place density at the longitudinal joint. Some decrease in the in-place density was observed at the 150-mm (6-in.) location in the second lane (hot side) when the notched-wedge joint was used.

Study of Longitudinal-Joint Construction Techniques in Hot-Mix Asphalt Pavements

There is a need to identify suitable longitudinal-joint construction techniques for multilane, hot-mix asphalt pavements that can minimize or eliminate cracking at the joint and raveling adjacent to the joint. It is believed that the longitudinal cracks result primarily from the density gradient that is usually encountered across the joint. This density gradient can be attributed to low density at the unconfined edge when the first lane is paved and relatively high density at the confined edge when the adjacent lane is paved. Seven different longitudinal-joint construction techniques were used on I-25 in Colorado in 1994, including various rolling procedures to compact the joint, provision of a vertical face with a cutting wheel, and use of rubberized asphalt tack coat on the face of the unconfined edge. Two longitudinal-joint construction techniques were used on I-79 in Pennsylvania in 1994: the conventional technique (control) and the New Jersey–type wedge joint. The latter technique uses a 3:1 taper at the unconfined edge of the first lane. The face of the taper is heated with an infrared heater before the adjacent lane is placed. Pavement cores were taken on the joint and 305 mm (1 ft) away from the joint for density measurements in all experimental test sections. Different techniques for joint construction have been ranked on the basis of statistical analysis of all density data. Various joints were also evaluated visually by teams of at least four engineers in June 1995. The performance, or ranking, of the joints in both Colorado and Pennsylvania projects after one winter seems to have been influenced by the overall density at the joint. The joints with high densities indicate better performance than those with relatively low densities. These rankings may change in the future on the basis of the long-term performance as measured by cracking and raveling.

Study of Longitudinal-Joint Construction Techniques in Hot-Mix Asphalt Pavements

There is a need to identify suitable longitudinal-joint construction techniques for multilane, hot-mix asphalt pavements that can minimize or eliminate cracking at the joint and raveling adjacent to the joint. It is believed that the longitudinal cracks result primarily from the density gradient that is usually encountered across the joint. This density gradient can be attributed to low density at the unconfined edge when the first lane is paved and relatively high density at the confined edge when the adjacent lane is paved. Seven different longitudinal-joint construction techniques were used on I-25 in Colorado in 1994, including various rolling procedures to compact the joint, provision of a vertical face with a cutting wheel, and use of rubberized asphalt tack coat on the face of the unconfined edge. Two longitudinal-joint construction techniques were used on I-79 in Pennsylvania in 1994: the conventional technique (control) and the New Jersey—type wedge joint. The latter technique uses a 3:1 taper at...

Keyed Joint Performance under Heavy Load Aircraft

The poor performance of keyed longitudinal construction joints in rigid airfield pavements under simulated C-5A traffic operations is presented. The data presented were collected from a full scale test track pavement supported on a low strength subgrade. No deficiencies in materials or construction were found which would have adversely affected the performance of the keyed joint. The failures observed in the keyed joint demonstrate that a balanced design will result using the Corps of Engineers keyed joint dimensions.