Jointed Pavements Research Articles

Effect of joint type on rigid airfield pavement behavior

The effects of dowel and key joints in the rigid airfield pavements on the stress distribution in the concrete slab and on the Load Transfer Efficiency (LTE) at joints were investigated in this study. Numerical analysis models including dowel and key joints of the rigid airfield pavements were developed to analyze behaviors under environmental and aircraft gear loads. The analysis results showed that under gear loads both the dowel and key joint pavement slabs had very similar stress distributions when the joint gap did not exist, but the key joint pavement slab had larger stresses than dowel joint one when the joint gap existed and the loads were applied near the joint. The LTEs at joints were excellent at both pavement slabs without a joint gap, but the LTE decreased significantly in the key joint pavement as the joint gap became larger. Under environmental loads, the stresses at both the dowel and key joint pavement slabs were almost the same and those increased slightly when there was a joint gap. When the rigid airfield pavement had only the dowel joints along both the longitudinal and transverse joints, there was no stress concentration in the slabs and the stresses were smaller and the LTEs were higher than the pavement that had the dowel joints along one direction and the key joints along the other direction, which was the current airfield pavement joint design in Korea. Keywords: rigid airfield pavement, dowel joint, environmental load, gear load, jointed concrete

Cracking in Concrete Pavements

Several theories explaining the mechanisms and intervals of cracking of portland cement concrete pavements are reviewed. For plain and jointed pavements, the cracking interval was found to be approximately twice (when expressed in feet) the strength (when expressed in psi) of the concrete. For new concrete with a 30-psi (0.2-MPa) tensile strength after only a few hours, the drying-shrinkage or cooling crack interval is approx 60 ft (18 m). This is a basis for sawing joints at approx 50 ft (15 m) intervals before the concrete is 16 hrs old. For concrete with a compressive strength of 4,500 psi (31 MPa) and sawed joints, the interval between blowups or crushed joints would be about 1 mile (1.6 km). This is the basis for spacing expansion joints approx 0.5 mile to 1 mile (0.8 km to 1.6 km) apart. A theory of differential temperature expansion-contraction between concrete and steel explains the ultimate crack interval of continuously reinforced concrete pavements between 2 ft and 6 ft (0.6 m and 2 m). This interval was verified by field observations.

EVALUATION OF I-75 LANE CLOSURES

A spot pavement replacement and joint sealing project on I-75 in southern Kentucky during the 1986 construction season involved numerous lane closures. Traffic congestion caused by heavy volumes and late merges resulted in the use of the following traffic control devices to supplement standard lane closure devices: variable message signs, supplemental lane closure warning signs, and rumble strips placed in the lane to be closed in advance of the taper. Because the devices were not typical applications for work zones and because of the potential for applications at other sites, an evaluation study was conducted. Results showed a decrease in the percentage of traffic in the lane to be closed with each successive traffic control device in addition to the standard lane closure devices. There was a general decrease in speeds as traffic approached the taper. The percentage of trucks in the lane to be closed was lower than the percentage in the open lane when the closure was a left lane. Hourly traffic volumes observed in this study (800 to 1,300 vph) did not appear to influence the percentage of traffic in the lane to be closed. The percentage of trucks in both lanes (8.5 to 14.7 percent) did not influence the percentage of traffic in the lane to be closed either. Recommendations from the study included the following: (a) supplemental signs for all long-term closures on high-volume, high-speed four-lane roadways, (b) variable message signs when one-way hourly volumes exceed 1,000 (ADT exceeds 20,000), and (c) application of rumble strips if other devices do not reduce late merges and there is excessive congestion.

A Study to Determine the Impact of Cracking on Load Transfer Efficiency of Rigid Airfield Pavements

Abstract The mechanistic evaluation of pavement utilizing full-scale test data is an important component to the study of pavement behavior. This study focuses on the use of concrete strain gages (CSG) and crack location data to evaluate the effect of localized cracking on the stress-based load transfer efficiency (LTE (S)) of transverse doweled pavement joints. Concrete strain gage data generated from the full-scale testing carried out by the Federal Aviation Administration (FAA) at the National Airport Pavement Test Facility (NAPTF) has been analyzed in this study. Load transfer efficiency was determined from paired concrete strain gages for the test vehicle moving in opposite directions at two specific locations, resulting in four distinct cases of LTE (S). It was found that LTE (S) varies as loading progresses on the test sections, especially after cracking near the joint has occurred on the slabs. The design constant of 25 % LTE (S) appears to be reasonably conservative before cracking occurs at the joint but overestimates joint LTE (S) thereafter. Additionally, peak strains from gages located at the joint can be used to evaluate the behavior of LTE (S) during the formation of cracks on the slab, in particular the case where the cracks have formed close to the doweled joint but are not yet visible on the surface.

Newly Developed Adhesive Strength Test for Measuring the Strength of Sealant between Joints of Concrete Pavement

AbstractA new adhesive strength test (AST) was developed to determine the adhesive strength of joint sealant. A series of sealant thicknesses, displacement rates, and curing times was tested to determine proper AST testing parameters using self-leveling (SL) and non-self-leveling (NS) silicone sealants. A series of tests was conducted under varying moisture conditions. The results appeared to indicate that moisture may reduce adhesive strength. Drying-time tests were conducted to determine the approximate appropriate wait time between joint washing and sealant installation for 3.2 mm (1/8 in.) and 9.5 mm (3/8 in.) joints. A series of tests was also conducted on artificially aged sealants, which appeared to indicate that oven aging reduces adhesive strength for SL sealant. Non-self-leveling sealant, on the other hand, appeared to be largely unaffected by oven aging. Hot-water aging and freeze-thaw aging appeared to reduce adhesive strengths for both sealant mixtures.

Analysis of Factors Influence on Void Underneath at Concrete Pavement Joints

Three-dimensional finite element analysis was made on the transverse joint stress state of the concrete pavement slab with void underneath using ANSYS. The transfer effect of dowel bar was discussed with aircraft loaded in the joints. The influence rule of load transfer effect under different dowel bar spacing and dowel bar cross section dimension was compared. Based on the results of finite element analysis, this paper had carried on the experimental study on stress-transferring effect on concrete pavement joints with different location of the dowel bar. The influencing factors of pavement slab transverse joint with void underneath and the resistance of pavement damage on the joint was analyzed. Theoretical analysis showed that in order to reinforce the resistance capacity of local cavity on concrete pavement joint, the largest spacing of transverse dowel bar set shall not be more than 45cm, and the main factors influencing the resistance void ability on the joint are top reaction modulus, coefficient of cavity, the concrete elastic modulus and coefficient of transverse reinforcement.

Evaluation of performance and design of GFRP dowels in jointed plain concrete pavement – part 1: experimental investigation

Dowel bars are provided at the transverse joints of the jointed plain concrete pavement to allow for expansion and contraction of the pavement due to moisture and temperature changes. This paper presents experimental and analytical investigations for the deflection response of glass fibre-reinforced polymer (GFRP) dowels for different joint widths and concrete grades. The results were compared with those obtained from investigations into the conventional epoxy-coated steel dowel bars of similar rigidity. The experimental results showed that the 38 mm (1.5 in.) GFRP dowels perform better in terms of joint face deflection compared with 25 mm (1 in.) epoxy-coated steel dowel bars. In addition, these results showed that the deflection of the GFRP dowel was significantly affected by changing the concrete compressive strength and the joint widths.

Three-Dimensional Finite Element Analysis of Doweled Joints in Concrete Pavements

Concrete pavements are usually selected by pavement engineers for roads subjected to heavy traffic loading and feature high maintenance and construction costs. As such, the structural behaviour of concrete pavements with doweled joints is evaluated herein using Finite Element Method. The pavement system is modelled using three-dimensional brick elements and five loading cases are applied to replicate realistic vehicular loadings approaching and leaving the joint. The structural behaviour of the pavement at the doweled joint is investigated for: (1) pavement with and without voids, and (2) different dowel bar spacing. The amount of load transfer was obtained from the shear force in the beam elements that simulate dowels. Results show that the voids underneath the joint causes an increase in the vertical displacement of the concrete slab and vertical stress at concrete/dowel bar interface which may result in crushing of the concrete and dowel loosening. Wider dowel spacings result in increased shear forces and the size of the region containing engaged dowels does not change significantly with dowel spacing, only effecting the distribution of shear forces. The study shows that the dowel bars perform effectively as a load transfer device in the concrete pavement system even under severe conditions.

Development of an Experimental Method for Asphalt Concrete Overlay Reflective Cracking Evaluation

From a concept normally used in metallic material science, the parameter ”Impact Toughness” was used in this study to evaluate the ability of various asphalt mixtures to resist reflective cracking in composite pavements. In this paper, Impact Toughness was defined as the area underneath the load-displacement curve of three point bending specimen subjected to impact loading. From fracture mechanics and energy principal, it was proved that the Impact Toughness of an asphalt mixture can be correlated to its ability of resisting reflective cracking; the higher the Impact Toughness value, the stronger the material. Further, the optimum testing temperature was determined to be 15°C, established from stress-temperature curves of six asphalt mixtures. The laboratory testing results indicated that the aggregate gradation and the asphalt binder type were major factors that influenced the mixtures' Impact Toughness. Dense graded asphalt mixtures had higher Impact Toughness value than gap graded and modified asphalt mixtures had higher value than unmodified ones. The maximum size of the aggregate used in the mixtures affected their Impact Toughness as well. To validate the test results, a pavement model consisting of an asphalt concrete overlay on top of a Portland cement concrete pavement joint was constructed and subjected to repeated loading of an Asphalt Pavement Analyzer (APA). The number of loading required for the crack to appear on the asphalt overlay surface was termed as the fatigue life. The results showed that there was an excellent linear relationship between the fatigue life of the pavement model and the Impact Toughness. Therefore, it is evident that the Impact Toughness of asphalt mixtures can represent the ability of the mixtures to resist reflective cracking and can provide guidance for asphalt mixture selection and design.

Accelerometer Measurements of Tire Tread Vibrations and Implications to Wheel-Slap Noise

ABSTRACT There are many analytical and finite element models for predicting vibration of a tire tread. However, experimental verification of these models is limited because of the difficulties involved in measuring vibration near the contact patch of the tire. In this research, a set of experiments were conducted using a microaccelerometer mounted against the tire tread, in the center of the tread pattern. The tire was mounted on Purdue University's tire-pavement test apparatus, a machine that allows precise measurements of tire noise and vibration as the tire rolls over samples of actual pavement. Microphone and accelerometer signals were recorded to determine the influence of pavement parameters on tire-pavement noise generation mechanisms. The vibration measurement and signal processing techniques are verified by comparing the results to published studies. The relationship between vibration characteristics and noise was investigated as a tire rolls over contraction joints in Portland cement concrete pavements. We found that although travelling waves are generated at the leading and trailing edge of the contact patch, the speed coefficients of increased noise and traveling wave amplitude do not match, and the wave speed of the impulse is that of an inefficient radiator. Therefore, increased tread vibration is not a major cause of increased noise at contraction joints, and other mechanisms must be involved.

Joint Issue Discussion on Cement Concrete Pavement

Concrete pavement joints are an important part of the cement concrete pavement, and joints are the weak link of the concrete pavement. It is also one of the main causes of early diseases and failure of cement concrete pavement. This paper summarizes the outcome of the predecessors, introduces the research status of the joints, and analysis the joint destruction and its cause from the point of view of the stress.

콘크리트 포장용 고내구성 대체 다웰바의 실내공용성 평가

PURPOSES: The problem under this circumstance is that the erosion not only drops strength of the steel dowel bar but also comes with volume expansion of the steel dowel bar which can reduce load transferring efficiency of the steel dowel bar. To avoid this erosion problem, alternative dowers bars are developed. METHODS: In this study, the bearing stresses between the FRP tube dowel bar and concrete slab are calculated and compared with its allowable bearing stress to check its structural stability in the concrete pavement. These comparisons are conducted with several cross-sections of FRP tube dowel bars. Comprehensive laboratory tests including the shear load-deflection test on a full-scale specimen and the full-scale accelerated joint concrete pavement test are conducted and the results were compared with those from the steel dowel bar. RESULTS: In all cross-sections of FRP tube dowel bars, computed bearing stresses between the FRP tube dowel bar and concrete slab are less than their allowable stress levels. The pultrusion FRP-tube dowel bar show better performance on direct shear tests on full-scale specimen and static compression tests at full-scale concrete pavement joints than prepreg and filament-winding FRP-tube dowel bar. CONCLUSIONS: The FRP tube dowel bars as alternative dowel bar are invulnerable to erosion that may be caused by moisture from masonry joint or bottom of the pavement system. Also, the pultrusion FRP-tube dowel bar performed very well on the laboratory evaluation.

Modeling of Slab–Foundation Friction in Jointed Concrete Pavements under Nonlinear Thermal Gradient or Traffic Loads

The accurate modeling of the thermomechanical response of jointed concrete pavements is of primary importance in the design of pavement sections. From the initial development of pavement analysis software in the early 1970s, it was recognized that the finite element method was the most appropriate modeling tool because of its potential ability to capture all pavement response features. A series of software development efforts have culminated in the production of NYSLAB, an analysis tool for jointed pavement that can predict the complete thermomechanical response, including pavement curling and interactions between slab and foundation. A series of studies were developed in NYSLAB specifically to look into slab–foundation friction generated by nonlinear thermal gradients and traffic loads. Nonlinear temperature gradients can produce slab expansion and contraction that lead to frictional traction between slabs and foundation. The prediction of these friction tractions is complicated by the curling of the slabs that cause some portions of the slabs to lose contact with the foundation. The results of the studies highlight the importance of considering these frictional tractions in the analysis of jointed concrete pavements because they have a significant impact on the bending stresses of portland cement concrete slabs.

Joint Resealing Project at Fairchild Air Force Base, Washington

In 1989, the U.S. Army Engineer Research and Development Center and Crafco, Inc., initiated a research effort to develop improved materials and processes for sealing joints in portland cement concrete pavements. Objectives were to develop specifications for improved hot-applied, jet fuel–resistant (JFR) and non–jet fuel–resistant (non-JFR) sealants and to determine the impact of installation configuration on field performance. The laboratory phase identified desired sealant properties, evaluated sealants for those properties, and developed sealants with improved low-temperature and aging properties. The field phase was installed in June 1991 at Fairchild Air Force Base, Washington, to determine performance of developed sealants compared with standard sealants and to determine whether performance could be improved by changing installation geometry. Thirteen sealants were installed. The field study documented installation and evaluations at 6 and 12 months. After study completion, the installations were monitored several additional times. Detailed papers were prepared after 5 and 10 years. At 10 years, some sealants had greater than a 10-year life. In 2011, the installations reached 20 years of age. The JFR sections had been replaced, and non-JFR sections were still intact and were evaluated in April 2012. Results of the 21-year evaluation are presented. One silicone sealant and the improved non-JFR sealant achieved a 21-year life. Results also show that the flush-fill installation geometry increased life of the hot-applied asphalt sealants by more than 50% compared with the standard recessed configuration and should be considered for joint sealant installations.

Fracture testing for the evaluation of asphalt pavement joints

Asphalt joints are inevitable parts of every pavement. Although much attention is dedicated to the construction of such joints, reliable tools for assessing the mechanical properties of joints for design and performance assessment are still scarce. This is particularly true for cold joints when attaching a new hot pavement to a cold existing pavement as in the case of large patches for pavement repair. This paper intends to evaluate different new or modified static fracture testing methods for ranking existing joint construction techniques. Some of these testing methods, such as indirect tensile test, direct tensile test and 4-point bending test are familiar in the field of asphalt pavement characterisation, but have scarcely been used for assessing the quality of joints so far. These three test types were adopted and evaluated for joints and the test results were analysed with finite element (FE) software ABAQUS. Different joints for testing were prepared in the laboratory using a special specimen construction procedure. The results suggest that joints with inclined interfaces seem to show more promising behaviour than vertical joints. It was confirmed that starting compaction from the hot side of the joint generally produces better results than compaction starting from the cold side of the joint. Pre-heating of the joint surface and using a bond sealant appears to provide the best results.

Detection of Subsurface Joint Deterioration

Results of a blind test evaluation of various nondestructive testing techniques, including well-established methods such as chain dragging, rod sounding, and ground-penetrating radar, compared with an emerging ultrasonic array technology for determining the extent of concrete joint deterioration, are presented. Nondestructive testing at two concrete pavement joints at the Minnesota Road Research Facility was performed, and the results were independently evaluated and submitted to the Minnesota Department of Transportation. Significant discrepancies in subsurface deterioration assessments were observed between these techniques. Forensic evaluation (trenching and coring) was used to resolve the discrepancies in test results. It was concluded that the ultrasound array analysis was the only method that could accurately determine the horizontal extent of the deterioration otherwise undetected by the other available nondestructive evaluation methods. Additionally, ultrasonic tomography analysis was able to determine the depth of the deterioration. These results make this emerging technology an attractive alternative to traditional nondestructive testing methods for assessment of concrete pavement joints.

Thermal Experiment of a Reinforced Approach Pavement for Semi-Integral Abutment Jointless Bridge

Semi-integral abutment fully jointless bridges, which connecting the main girder, the approach slab and the reinforced approach pavement all together and eliminating all the deck expansion joints and also the approach reinforced pavement joint is studied. As we know, the temperature variation is the key influence factor of the basic performance of the fully jointless bridges. When the temperature drops, the cracks appeared along the reinforced approach pavement. In the paper, emphasisis primarily made on simulating the temperature drops. A 28m full scale model stretching experiment simulating the temperature drops has been carried out in laboratory. After the experiment simulation we found that:(1)The crack width of approach pavement distribute uniformly at the pre-cut joints and their crack widths ranged mainly between 0.2mm and 0.8mm and the mean crack width was 0.37mm when the maximum stretch length at the end of the approach slab reached 9.87mm, which was within AASHTO and the Chinese highway pavement specification allowable value; (2)the load transfer capability coefficient at the third pre-cut joint with the maximum crack width (0.97mm) was 84%,which also satisfied the allowance of Chinese highway pavement specification. So this reinforced approach pavement is safe to connect semi-integral abutment bridge for the temperature length of 45m with the maximum temperature decrement of =20 ºС from the average reference construction temperature.

The Dowel Group Action in Jointed Concrete Pavement

The wheel load transfer across a joints in concrete pavement is accomplished mainly by dowel bar system, dowels are installed in order to allow shear load transfer across slab joints. The dowel group action has been examined in this paper via from using of 3-D FE mode. Numerical model results are presented in four formats in this study, including shear force diagram, load transfer ratio by shear force, dowel shear force distribution and dowel shear ratio. The relationships between applied wheel load and dowel group action will be useful in the design and evaluation of dowel jointed concrete pavements.

박스형 암거와 보강슬래브에 의한 줄눈 콘크리트 포장의 거동

PURPOSES : Hollows are easily made, and bearing capacity can be lowered near underground structures because sublayers of pavement settle for a long time due to difficult compaction at the position. If loadings are applied in this condition, distresses may occur in pavement and, as the result, its lifespan can decrease due to the stress larger than that expected in design phase. Although reinforced slab is installed on side of box culvert to minimize the distresses, length of the reinforced slab is fixed as 6m in Korea without any theoretical consideration. The purpose of this paper is investigating the behavior of concrete pavement according to the cover depth of the box culvert ad the length of the reinforced slab. METHODS : The distresses of concrete pavement slabs were investigated and cover depth was surveyed at position where the box culverts were located in expressways. The concrete pavements including the box culverts were modeled by finite element method and their behaviors according to the soil cover depth were analyzed. Wheel loading was applied after considering self weight of the pavement and temperature gradient of the concrete pavement slab at Yeojoo, Gyeonggi where a test road was located. After installing pavement joint at various positions, behavior of the pavement was analyzed by changing the soil cover depth and length of the reinforced slab. RESULTS : As the result, the tensile stress developed in the pavement slab according to the joint position, cover depth, and reinforced slab length was figured out. CONCLUSIONS : More reasonable and economic design of the concrete pavement including the box culvert is expected by the research results.

A Study on the Working Performance of Dowel Bars with Horizontal Installation Errors

AbstractUsing the pullout test on dowel bars with different surface treatment modes and position deviations, the present paper draws the conclusion that plastic-spraying treatment on different surface treatment modes can meet the maximum setting requirements for dowel bars and that the angular deviation of the dowel bar is the main reason for the cracking within 50 cm on both sides of the cement concrete pavement joint. Using the bending fatigue test, the present paper evaluated the attenuation law of the joint load transfer capacity under different horizontal installation error conditions (0°, 5°, 10°, and 15°) and found that the initial joint load transfer capacity showed fast downward trend with increase in dowel bar deviation angle and that the performance during the entire working period became increasingly worse. When the angular deviation of dowel bar along the horizontal plane was not more than 5°, juncture load transfer capacity can still remain on the medium level, which will not have too much i...