Jointed Plain Concrete Pavement Research Articles

Gray Clustering-Based Pavement Performance Evaluation

In the Mechanistic Empirical Pavement Design Guide MEPDG, rather than producing a quantitative overall evaluation index, several performance measures are used to separately evaluate the pavement performance condition for rehabilitation design. Due to the characteristics of information on parameters being partially known during the evaluation process, there exist several limitations of the current evaluation methods. In this paper a gray clustering-based methodology is proposed to comprehensively evaluate existing pavements following the MEPDG framework. Gray clustering method is one pillar part of the gray system theory, which was proposed in the 1980s to solve problems with partially known information. The performance criteria used in this study are selected from those defined in MEPDG. The analysis data sets are obtained from the long-term pavement performance LTPP database for three types of pavements: flexible pavement, jointed plain concrete pavement, and continuous reinforced concrete pavement. Many LTPP pavement sections are evaluated using the proposed methodology and comparisons are made between gray clustering-based method and extension theory-based approach. It is shown that the proposed gray clustering-based method is able to quantify pavement performance and is suitable to be used as a practical pavement evaluation tool for highway agencies.

Evaluation of international roughness index for asphalt overlays placed over cracked and seated concrete pavements

Crack, seat and overlay (CS&O) is a rehabilitation technique that has been used on jointed plain concrete pavements. Only a few studies have evaluated the surface roughness of pavement sections rehabilitated using this technique. The purpose of this paper was to evaluate the roughness of roadway sections rehabilitated employing the CS&O technique. The data extracted from the long-term pavement performance database were separated based on the weather region and analysed. Then, international roughness index (IRI) prediction models were developed. A separate model was developed for pavement sections in California. For sections with bound bases, thick overlays provide a smoother surface (lower IRI). However, the effect of the overlay thickness on the IRI for sections with unbound bases does not appear to be considerable. Prediction models developed in this study are shown to provide adequate predictive capabilities. Sections in California have initial IRI values that are lower than those found for sections in the wet-with-freeze (WF) and wet-with-no-freeze (WNF) regions. However, California sections are predicted to develop higher IRI values over time, when compared to those sections in the WF and WNF regions.

Sensitivity Analysis of Rigid Pavement Systems Using the Mechanistic-Empirical Design Guide Software

Initiatives are underway to implement the new mechanistic-empirical pavement design guide (MEPDG) in Iowa. This paper focuses on the sensitivity study of jointed plain concrete pavements (JPCP) and continuously reinforced concrete pavements (CRCP) in Iowa using the MEPDG software. In this comprehensive study, the effect of MEPDG input parameters on the rigid pavement performance is evaluated using the different versions of the MEPDG software (0.7, 0.9, and 1.0) available to date. Representative JPCP and CRCP sections in Iowa were selected for analysis. Based on the sensitivity plots obtained from the MEPDG runs, the design input parameters were categorized as being most sensitive, moderately sensitive, or least sensitive in terms of their relative effect on distresses. In this study, the curl/warp effective temperature difference, the PCC coefficient of thermal expansion, and PCC thermal conductivity had the greatest impact on the JPCP and CRCP distresses. Compared to the original version of MEPDG software (Version 0.7), the updated versions (Versions 0.9 and 1.0) are more sensitive to inputs, which shows the evolution of engineering reasonableness.

Evaluation of Coefficient of Thermal Expansion Test Protocol and Its Impact on Jointed Concrete Pavement Performance

In order to determine the typical concrete paving mixture thermal expansion coefficient (CTE sub PCC) with mixture coarse aggregate derived from eight different Michigan sources, a laboratory investigation was conducted. Trap rock, gravel, slag, dolomite, and limestone were included in the primary aggregate class. The provisional AASHTO TP60 protocol was used to determine the CTE sub PCC. For each mixture-age combination, there was fabrication of three replicate test specimens. Prior to testing, there was moist curing of the test specimens for 3, 7, 14, 28, 90, 180, and 365 days. There was a 4.51 to 5.92 μe per degree F (8.11 to 10.65 μe per degree F) value range for average measured CTE sub PCC. That the number of heating and cooling cycles that the specimen is subjected to, the age of specimen at time of testing, and aggregate geology have statistically significant impacts (at 95% confidence level) on measured CTE sub PCC magnitude is indicated in test results. The test variables' practical impact on jointed plain concrete pavement transverse cracking performance is also discussed.

Top-Down Cracking of Jointed Plain Concrete Pavements

Top-Down Cracking of Jointed Plain Concrete Pavements

Smoothness variations in early-age jointed plain concrete pavements

This paper discusses the variations in the early-age pavement smoothness at different measurement times and locations in three jointed plain concrete pavements (JPCPs) representing different ranges of construction times. Surface profile measurements were made during the early morning and late afternoon hours at different locations of the instrumented JPCPs during the first 7 d after construction. Variations in pavement temperature during this critical period were monitored using temperature sensors installed within the test sections. The results show that measurable changes of early-age jointed plain concrete pavement (JPCP) smoothness do occur at different measurement times and locations. Within the scope of this study, it can be concluded that the variations in early-age JPCP smoothness can be significant from the standpoint of smoothness specifications. The findings of this study also indicate that morning paving produces consistent smoothness measurements when compared with afternoon paving.

Environmental effects on development of pavement joint cracks

A test road consisting of jointed plain concrete pavement divided into 22 sections was constructed by the Korea Highway Corporation to investigate the environmental effects on the development of joint cracks. These 22 sections were observed for approximately three to seven weeks after construction. The pavement placed in the morning presented a higher rate of crack development at the saw-cut joints, due to a positive built-in temperature difference. Additional joint cracking was delayed for a few days after construction because the pavement was exposed to rainfall. For pavement sections placed in the afternoon, drying shrinkage appeared to have a greater effect on crack initiation at the saw-cut joints than temperature did up to three or four days after placement, when tensile creep had decreased sufficiently. The effect of joint crack time on the long-term joint behaviour was also investigated in the test road two years after placement of the concrete.

Rehabilitation Design of Jointed Plain Concrete Pavement

Unbonded jointed plain concrete (JPC) overlay is a viable rehabilitation technique for distressed jointed plain concrete pavement (JPCP). The design of unbonded JPC overlays requires performing minimal repairs to the existing JPCP, placement of an asphalt separator layer between the existing portland cement concrete (PCC) layer and the overlay design (determination of overlay PCC thickness), and placement of the overlay. Concrete overlay thickness typically is determined with mechanistic-based design procedures that require a knowledge of existing pavement layer types, thicknesses, and moduli. The existing PCC thickness and elastic modulus can be determined easily through coring and laboratory testing or nondestructive testing by using the falling weight deflectometer. However, establishing an appropriate PCC elastic modulus value that represents the existing damaged pavement is more challenging because coring and deflection testing typically are done on intact (uncracked or deteriorated) PCC material obtained from the sections of the existing JPCP that is in relatively good condition. Therefore, PCC elastic moduli estimated from these sources are not representative of the entire JPCP condition. Various empirical rigid pavement design procedures have been developed for adjusting intact PCC elastic modulus values into a more appropriate damaged PCC elastic modulus for JPCP overlay design. Analysis done to characterize the elastic modulus of damaged, cracked, or shattered PCC slabs based on backcalculated PCC elastic modulus and existing JPCP condition is described.

Neural Network-Based Approach for Analysis of Rigid Pavement Systems Using Deflection Data

This paper focuses on the development of backcalculation models based on artificial neural networks (ANNs) for predicting the layer moduli of the jointed plain concrete pavements, that is, the elastic modulus of the portland cement concrete (PCC) layer and the coefficient of subgrade reaction for the pavement foundation. The ANN-based models were trained to predict the layer moduli by using the falling-weight deflectometer (FWD) deflection basin data and the thickness of the concrete pavement structure. The ISLAB2000 finite element program, extensively tested and validated for more than 20 years, has been employed as an advanced structural model for solving the responses of the rigid pavement systems and generating a knowledge database. ANN-based backcalculation models trained with the results from the ISLAB2000 solutions have been found to be viable alternatives for rapid assessment (capable of analyzing 100,000 FWD deflection profiles in a single second) of the rigid pavement systems. The trained ANN-based models are capable of predicting the concrete pavement parameters with very low (<0.4%) average absolute error values. The ANN model predictions and closed-form solutions were compared through the use of the FWD deflection data, and the results are summarized in the paper. In addition, a sensitivity study was conducted to verify the significance of the layer thicknesses and the effect of bonding between the PCC and the base layer in the backcalculation procedure. The results of this study demonstrated that the ANN-based models are capable of successfully predicting the rigid pavement layer moduli with high accuracy.

Application of Rolling Dynamic Deflectometer to Forensic Studies and Pavement Rehabilitation Projects

Characterization of the load transfer of jointed plain concrete pavements requires proper tools. The rolling dynamic deflectometer (RDD) has been used successfully on many Texas Department of Transportation projects for this purpose. Applications of the RDD in forensic studies and pavement rehabilitation projects are presented. RDD deflection profiles were used to assist in diagnosing the causes of reflective cracks on SH87a, where a reflective crack relief interlayer was placed in a rehabilitation project to minimize reflective cracking. However, frequent and severe reflective cracks still occurred on SH87a in the turning and inside lanes, where traffic is lighter than in the outside lane. It was concluded that poor load transfer at joints (indicated by high relative vertical movements) was one of the main contributing factors to the reflective cracking in these two lanes. Two rehabilitation projects are also presented to show how continuous RDD deflection profiles were critical to the success of the projects. In the BU287 project, RDD profiles were used to identify successfully locations for full-depth repair in Subsection 1 and recommend a different rehabilitation strategy (remove and reconstruct) in Subsection 2 because of the significant number of joints that have a severe potential for reflective cracking. In the SH87b rehabilitation project, the RDD was employed to identify locations that need dowel bar retrofit and other locations that need full-depth repair. It is concluded that RDD data not only are able to provide 100% coverage but also offer quantifiable and objective information for forensic and rehabilitation studies in terms of relative movements at joints and cracks.

Structural Response of Concrete Pavements under Moving Truck Loads

While there has been a great deal of research conducted on concrete pavement performance and deterioration under static loads, only very limited research has been carried out on its dynamic response. Furthermore, opinions differ as to which type of loading (static or dynamic) results in greater values of slab deflection or flexural stress. In the present study, a test section consisting of two jointed reinforced concrete pavement and two jointed plain (unreinforced) concrete pavement was constructed and tested under both quasistatic and dynamic truck loads. Truck load was allowed to wander at predetermined locations on the instrumented pavement at speeds from 5 to 55 km/h. Strain gauges and displacement transducers were installed along the test section to monitor the pavement responses. Time history responses of the test section were recorded and used to validate a finite-element model developed in the ANSYS platform for further sensitivity study on those parameters affecting the dynamic response of concrete pavements. Results indicate the significance of dynamic amplification in concrete pavement design.

Initial smoothness of concrete pavements under environmental loads

In the current paper, the effect of curling and warping, caused by environmental ambient conditions, on the initial smoothness of concrete pavements is discussed. Surface profile measurements were made during the hours of the early morning and late afternoon on an instrumented jointed plain concrete pavement (JPCP) on highway US-30 near Marshalltown, Iowa during the first seven days after construction in summer 2005. Variations in temperature and moisture during this critical period were monitored using the temperature and relative humidity sensors installed within the test sections at the time of construction. Based on the measured surface profile data, it was observed that the initial pavement smoothness, in terms of international roughness index (IRI) and the ride number (RN), was not significantly influenced by the early-age curling and warping behaviour of the JPCP. Using finite-element modelling (FEM), sensitivity studies were conducted to investigate the influence of slab curvature on initial pavement smoothness for a range of equivalent temperature differences between the top and bottom of the slab. The results indicated that the initial JPCP smoothness is sensitive to changes in slab curvature resulting from environmental ambient conditions only at higher magnitudes. Although the FEM-based IRI predictions were higher than the surface profile-based IRI values, the differences were not significant.

Fracture Mechanics Analysis for Saw Cutting Requirements of Concrete Pavements

Concrete sawing operations are performed at predetermined locations within the first 24 h to prevent random cracking on jointed plain concrete pavements. In current construction procedures, the depth and timing of the saw are usually established by the contractor on the basis of experience. A study analyzed the effect of several concrete mixture proportions and constituents on the early-age fracture properties and their effect on saw cut timing and depth for concrete pavements with several slab geometries. Concrete pavement mixtures with different coarse aggregate size and cementitious content were evaluated to determine sensitivity of the measured fracture properties on saw cut model predictions. Finite element analysis was used to derive the geometric correction factors necessary to characterize the fracture properties of concrete based on the wedge splitting test configuration. A saw cut depth model previously proposed was modified to determine the timing and depth of notches on jointed plain concrete pavements. The theoretical analysis and practical example lead to the observation that if greater time is desired before saw cutting, the design should favor concrete materials with slower development of fracture properties. Thinner concrete pavements also require significantly deeper notch depth ratios relative to those of thicker slabs.

Environmental Effects on Deformation and Smoothness Behavior of Early-Age Jointed Plain Concrete Pavements

In this paper, a study of environmental effects on the deformation and smoothness behavior of jointed plain concrete pavement (JPCP) during its early age is presented. A newly constructed JPCP on US-34 near Burlington, Iowa, was instrumented and monitored during the critical time immediately following construction to identify its early-age behavior regarding temperature variations. The surface profiles were measured in diurnal cycles. The primary objective of this research was to investigate the effect of the early-age curling and warping behavior on the initial smoothness of newly constructed JPCPs. Variations in temperature during these critical periods were monitored by temperature sensors installed within the pavement test sections at the time of construction. The slab deformations associated with environmental loading were quantified, and the smoothness indices (international roughness index and ride number) were computed from measured pavement surface profiles. The changes in smoothness indices at different measurement times were investigated and compared with those obtained with finite-element simulations. On the basis of variations in measured and predicted smoothness indices, it was observed that the initial pavement smoothness might be influenced by curling and warping behavior of JPCPs (during the first 7 days after paving).

Ultrathin Bonded Wearing Course as Pavement Preservation Treatment for Jointed Concrete Pavements

Use of an ultrathin bonded wearing course (UTBWC) is reported on as a pavement preservation strategy for jointed plain concrete pavements. This strategy has been used in North Carolina on both urban and rural sections. One of the benefits of the UTBWC is that the elevation change is small, typically 5/8 in. Expenses associated with thick overlays—such as adjustments to signs, guardrails, bridge clearances, and shoulders—are minimized. The effectiveness of the UTBWC in improving ride quality and extending pavement life is evaluated for five projects. North Carolina performs pavement condition surveys every year on the Interstate system and every other year on other systems. On jointed concrete pavements, a sample of 39 to 41 slabs is used for the first 0.1 mi of each mile. Asphalt-surfaced roadways are evaluated by using 100% coverage in a windshield survey. Application of the ultrathin bonded overlays resulted in a dramatic bump in the pavement condition ratings (PCRs). The rate of decline of the PCR after resurfacing with UTBWC is between 0.8 and 3.0 points per year on the basis of two sites. Most decline in PCR to date is associated with reflection cracking, which appears but does not degrade rapidly. Faulting ultimately results in decreased ride quality over time as indicated by increases in international roughness index (IRI). The rate of increase in IRI ranged from 0.5 to 2.1 points per year. On the basis of North Carolina's experience with UTBWC on poor-quality jointed portland cement concrete, a life of 6 to 10 years is attainable and is supported by the projections of performance curves from two of the sites.

Subsurface Drainage and Premature Distresses in Concrete Pavement

Field and laboratory forensic investigations were used to identify the failure mechanism of a jointed plain concrete pavement with a subsurface drainage system in Virginia. Similar to many states' practice, this subsurface drainage system consists of open-graded drainage layer and edge drains to provide positive drainage for the pavement. The investigation included a review of construction practices and pavement performance records, a visual distress survey, nondestructive testing using a falling weight deflectometer, roughness measurements using a profiler, coring and boring for materials testing, observation wells, subgrade soil classification, mineralogy, determination of concrete compressive strength, edge drain camera inspection, and slab removal. On the basis of the investigation, it was concluded that lack of positive drainage along with heavily loaded truck traffic resulted in premature failure. The water entering the pavement because of poor joint sealing was trapped in the open-graded drainage layer; this led to severe faulting, midslab cracks, pumping, and eventual failure of the pavement.

Guidelines for Joint Depth Determination and Timing of Contraction Joint Sawcutting for JCP Analyzed with Fracture Mechanics

An experiment with the objective of providing guidelines for joint depth determination and timing of contraction joint sawcutting to avert uncontrolled cement concrete pavement cracking has been conducted. Theoretical analysis and laboratory tests were performed to help in understanding and analyzing the field observation. Using two-dimensional elastic fracture mechanics, the influence of several parameters on crack propagation was delineated by a parametric study, involving initial notch ratio, joint spacing, Young's modulus and thermal expansion coefficient of concrete, temperature gradient, and modulus of subgrade reaction. Bimaterials made of rock plus cement mortar and rock plus polymer mortar were applied to the concrete in a field test section, and they were subjected to fracture tests. These tests have shown that fracture mechanics is a powerful tool not only in judging the quality of the jointed cement concrete pavement but also in providing a criterion for crack propagation and delamination. Based on fracture mechanics, a method is proposed to determine the joint depth, sawcut timing, and spacing of the jointed cement concrete pavement. This method has successfully been applied to a test section in Seohaean expressway. This study also summarizes the research results obtained from a field test for jointed plain concrete pavement, which was also carried out on the Seohaean expressway.

Quantifying built-in construction gradients and early-age slab deformation caused by environmental loads in a jointed plain concrete pavement

Construction curling and warping produces a built-in gradient, which takes place as the result of changes in temperature and moisture that occur prior to the hardening of Portland cement concrete (PCC) pavements. The slab remains flat in the presence of this gradient because the plastic concrete has not developed sufficient stiffness to generate stress or strain. The new Guide for the Design of New and Rehabilitated Pavement Structures has shown the importance of quantifying the built-in gradient. In this study, the magnitude of the built-in gradient was quantified along with the early-age response of the slab to environmental loads. It was found that the equivalent linear temperature gradient at the time of set was < 0.09°C/cm (0.55°F/in.). The largest built-in curvature measured along the diagonal for the restrained and unrestrained slabs was 0.0000124 1/m (0.0000408 1/ft) and 0.0000138 1/m (0.0000454 1/ft), respectively. The increase in curvature with an increase in equivalent linear temperature gradient for the unrestrained slabs was 7% higher than the restrained slabs. The profiles also indicated that the slab edges are, at times, completely unsupported.

Analytical procedures for evaluating factors that affect joint faulting for jointed plain concrete pavements using the Long-Term Pavement Performance database

The objective of this study was to identify and quantify design and construction features most important to joint faulting of joint plain concrete pavements. With data obtained from the Long-Term Pavement Performance (LTPP) database, an analysis approach that combined pavement engineering expertise and modern data analysis techniques was to develop guidelines for improved design and construction of Portland cement concrete (PCC) pavement. The approach included typical preliminary analyses, but emphasis was placed on using a series of multivariate data analysis techniques. Discriminant analysis was used to develop models that classify individual pavement into performance groups developed by cluster analysis, which was used to partition the pavements into three distinct groups representing good, normal, and poor performance. These models can be used to classify and evaluate additional or new pavements performance throughout the pavement's design life. To quantify the levels of the key design and construction features that contribute to performance, the classification and regression tree procedure was used to develop tree-based models for performance measure. The analysis approach described was used to develop the guideline on the key design and construction features that can be used by designers to decrease joint faulting of jointed plain concrete pavements (JPCPs).Key words: faulting, Long-Term Pavement Performance (LTPP), jointed plain concrete pavement (JPCP), cluster analysis, discriminant analysis, classification and regression tree (CART) analysis.

Characterizing Strain Induced by Environmental Loads in Jointed Plain Concrete Pavements: Immediately After Paving and Throughout First 10 Months

The focus of this study is to provide a detailed analysis of the strain that develops as a result of environmental loads. The study characterizes slab response immediately after construction (first 72 h after paving) and also addresses seasonal effects over the first 10 months following construction. A heavily instrumented test section was constructed on SR-22 in Murrysville, Pennsylvania, to help characterize slab response to environmental loads better. Static strain and climatic data collected through the first 10 months after construction (August 2004 through June 2005) were analyzed to interpret pavement response to environmental loads as a function of location with respect to joint proximity, depth within the slab, and level of restraint applied to the slab. Many things were also learned about the strain that develops in the slab over the first 10 months after construction. The average strain in the fall was around -450 μstrain, whereas the average strain in the winter was -600 μstrain. The ambient t...