Paper No Field Evaluation and Cost Effectiveness of the Saw and Seal Method to Control Reflection Cracking in Composite Pavements

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1 Paper No Field Evaluation and Cost Effectiveness of the Saw and Seal Method to Control Reflection Cracking in Composite Pavements Duplication for publication or sale is strictly prohibited without prior written permission of the Transportation Research Board Title: Field Evaluation and Cost Effectiveness of the Saw and Seal Method to Control Reflection Cracking in Composite Pavements Authors: Mostafa E. Elseifi, Rakesh Bandaru, Zhongjie "Doc" Zhang, and Said Ismail Transportation Research Board 90 th Annual Meeting January 23-27, 2011 Washington, D.C.

2 Field Evaluation and Cost Effectiveness of the Saw and Seal Method to Control Reflection Cracking in Composite Pavements Mostafa A. Elseifi Assistant Professor Department of Civil and Environmental Engineering Louisiana State University 3506 Patrick Taylor Hall, Baton Rouge, LA Rakesh Bandaru Graduate Research Assistant Department of Civil and Environmental Engineering Louisiana State University 3506 Patrick Taylor Hall, Baton Rouge, LA Zhongjie "Doc" Zhang Pavement Geotechnical Research Administrator Louisiana Transportation Research Center Louisiana State University 4101 Gourrier Ave., Baton Rouge, LA Said Ismail Management Systems Engineer Louisiana Department of Transportation and Development Office of Planning and Programming Telephone: (225) Fax: (225) Submitted to: 90 th Transportation Research Board Annual Meeting January 23 27, 2011 Washington, D.C. Word Count Text 4415 Figures 10 x 250 Tables 2 x 250 Total 7415

3 Elseifi, Bandaru, Zhang, and Ismail 3 ABSTRACT The Louisiana Department of Transportation and Development (LADOTD) had tested various techniques and treatments to control reflection cracking in composite pavements since the 1970s; however, the performance and cost-effectiveness of these methods had not been consistently evaluated. The objective of this study was to evaluate the performance of Hot-Mix Asphalt (HMA) overlays of Portland Cement Concrete Pavements (PCCP) sections built with the saw and seal method across the state and to assess the cost-effectiveness of this treatment method. To achieve this objective, projects with sufficient years in service and with available untreated segments were selected for detailed performance and economic evaluation. In total, the performance of 15 different pavement sections that were constructed with the saw and seal method was monitored for a period ranging from six to 14 years. Based on the results of this analysis, it is concluded that the majority of the sites showed a positive improvement due to the use of the saw and seal method. Forty percent of the sections showed an improvement from 1 to 3 years and 47% of the evaluated sections showed an improvement in service life ranging from 4 to 12 years. The average level of improvement to the pavement service life was 4 years. The vast majority of the sections (80%) indicate that the saw and seal method is cost-effective as compared to regular HMA overlays. This treatment method appears to be more cost-effective for low to medium traffic volumes. Finite element (FE) results validated that the constructed joints in the HMA overlay allow it to move with the underlying layer and to dissipate the energy generated due to expansion and contraction in the concrete layer and wheel loading without cracking. Keywords: Saw and Seal method, reflection cracking, rehabilitation

4 Elseifi, Bandaru, Zhang, and Ismail 4 INTRODUCTION Reflection cracking is caused by discontinuities (cracks or joints) in underlying layers, which propagate through a hot-mix asphalt (HMA) overlay due to movement at the discontinuity prompted by thermal and traffic loading. If the new overlay is bonded to the distressed layer, cracks in the existing concrete pavement usually propagate to the surface within one to five years; as early as few months have been reported (1). Reflection cracking leads to premature failure of the overlay and allows water infiltration through the cracks, which cause stripping in HMA layers and weakening and deterioration of the base and/or subgrade. One of the most popular treatment methods used in Louisiana to delay the reflection of cracks is to saw and seal the transverse and longitudinal joints on HMA overlays of Portland Cement Concrete Pavements (PCCP). This treatment involves sawing of the HMA overlay at the exact locations of the joints in the concrete pavement. The saw cut portion is then sealed with a rubberized low modulus sealant. While this treatment method has been used in various pavement sections in Louisiana, the performance of these projects had not been reliably evaluated. In addition, factors that may affect the performance of this treatment method should be identified to ensure that the treatment is only used when a positive outcome is expected. This would also allow quantifying the cost-effectiveness of this treatment method in controlling reflection cracking. The objective of this study was to evaluate the performance of HMA overlays with the saw and seal method across the state and to assess the cost-effectiveness of this treatment method in HMA overlays of PCCP. To achieve this objective, pavement sections in which the saw and seal method was used, were indentified through district surveys and by analyzing the Louisiana Department of Transportation and Development (LADOTD) Pavement Management System (PMS). Projects with sufficient years in service and with available untreated segments were selected for detailed performance and economic evaluation by analyzing collected data and by reviewing video crack surveys. Performance was assessed in terms of cracking, rutting, and roughness as described by the Pavement Condition Index (PCI). Results of this analysis quantified the performance and cost-effectiveness of this treatment method in controlling reflection cracking in rehabilitated pavements. BACKGROUND Reflection of cracks in HMA overlay represents a serious challenge associated with rigid pavement rehabilitation. Since the early 1930s, considerable resources and efforts have been spent to find new and relatively inexpensive techniques to delay reflection cracking (2). The saw and seal method is a treatment used to prevent random propagation of reflection cracking from underlying Portland Cement Concrete (PCC) joints to the top of an HMA overlay. The saw and seal method consists of sawing the HMA overlay to create transverse and longitudinal joints at the exact locations of the PCC joints followed by sealing of the constructed joints. Saw and seal operation should be performed promptly after placement of the overlay but at least 48 hours after paving (3). Success of the saw and seal method depends on applying the treatment at the exact locations of the joints (4). Prior to the overlay, existing joints on the concrete pavement are located and marked. Joints are then reestablished with a chalk after the overlay. These joints are dry cut using a rideable concrete saw. The cuts are cleaned prior to placing the sealant. The cleaning process involves usage of hot compressed air to get rid of all

5 Elseifi, Bandaru, Zhang, and Ismail 5 the dust particles, loose debris and most importantly, moisture that clings to the walls of the groove. For cleaner joints, a sand blaster may be used to remove any remaining debris. The final step is to seal the joints with a low-modulus rubberized sealant (5). Most of the grooves are overfilled from bottom up and then followed by squeegeeing to flush the applied sealant with the pavement surface. It was observed that sealant cools and contracts quickly once the squeegeeing process is completed. Sealing the created joints prevents the infiltration of water and incompressible materials from getting into the underlying layers. Since water infiltration and the possible stripping of HMA accelerate pavement deterioration, sealing the overlay joints properly plays an instrumental role in extending pavement service life (6). Field Evaluation of Saw and Seal Treatment Field performance of the saw and seal method in composite pavements was evaluated by various investigators. A seven year field evaluation of crack control treatments (saw and seal method, fabrics, membranes, and fiber glass laminates) was conducted in New York (7). In this controlled experiment, sections with two joint spacings were built on top of concrete pavements and were monitored for seven years. Field evaluation included visual surveys, deflection testing, coring, and materials testing. Performance was assessed in terms of crack extent and severity as well as load transfer efficiency across the cracks. Results of the evaluation determined that the saw and seal method was the best performer of all the considered treatment methods. In addition, this study concluded that a joint spacing of 4.6 m reduces the severity of reflection cracking as compared to a joint spacing of 6.1 m. An experimental study conducted in North Dakota monitored the performance of 54 sawed and sealed joints after a 100 mm overlay was placed on top of an existing PCC pavement (4). Coring conducted in the sawed and sealed joints indicated that the constructed joints converged with the overlying pre-sawed PCC joints. After seven years in service, the test section was performing satisfactorily with only a few spalls in the driving lane. However, it was observed that longitudinal cracks developed between the joints in the shoulder area. Based on these results, this study recommended that this treatment method be considered in the rehabilitation of existing PCC pavements as it provides low maintenance cost and good riding quality. The field performance of 10 projects constructed with HMA overlays treated with the saw and seal method was evaluated (8). These sites, which were located in six states, were evaluated through condition surveys, roughness measurements, and deflection testing. Selected sites had been in service for a period ranging from 2 to 10 years and with an overlay thickness ranging from 50 to 115 mm. Based on the results presented in this study, it was concluded that the saw and seal method reduces pavement roughness by 20% and transverse reflection cracking by as much as 64%. However, it was noted that a saw cut more than 25 mm away from the joint would result in secondary cracking. From the presented studies and others available in the literature, there is a general agreement that the saw and seal method is effective in controlling reflection cracking in composite pavements. However, the levels of improvement in extending pavement service life have not been quantified. In addition, the cost-effectiveness of this treatment method has not been evaluated.

6 Elseifi, Bandaru, Zhang, and Ismail 6 IDENTIFICATION OF CANDIDATE SITES Sections built with the saw and seal method across the state were indentified through district surveys and by reviewing the LADOTD pavement management system database. Since these sites were not built for experimental evaluation, untreated segments were not readily available. For the purpose of this study, untreated sections were selected by identifying the pavement sites located either before or after the treated sections. One limitation of this approach is that the treated and untreated segments may have not been constructed in the same year. However, as verified by reviewing the design plans and LADOTD databases, the traffic level and pavement design on the treated and untreated segments were comparable. Based on this approach, sites with sufficient years in service and with available untreated segments were selected for detailed performance and economic analysis, see Figure 1. In total, 15 in-service pavement sites were identified that were built in or before 2004 with the saw and seal method on top of a PCC pavement FIGURE 1 Location of the Evaluated Sites Table 1 presents a description of the sites that were selected for detailed performance and economic analysis. As shown in Table 1, traffic volume widely varied in the selected sections from an Annual Average Daily Traffic (AADT) of 1,800 to 50,250; these traffic volumes range from low to heavy. For the untreated segments, the AADT varied from 1,320 to 50,250. Three of the sections were located on the Interstate Highway System. It is noted that Louisiana is

7 Elseifi, Bandaru, Zhang, and Ismail 7 characterized by a humid subtropical climate with hot and humid summers and mild winters. Throughout the year, the temperature varies from a low of 8 C in the winter to a high of 38 C in the summer in the southern part of the state. In the northern part of the state, temperature varies from a low of -8 C in the winter to a high of 41 C in the summer. Precipitation is heavy especially in the summer months and is mostly rain. Therefore, one may assume that thermal loading in the presented analysis is not as critical as in other parts of the US. TABLE 1 Description of the Different Sites Evaluated in this Study Treated Untreated Site ID Constr. AADT AADTT Length Constr. AADT AADTT Length Date (Km) Date (Km) Route 1 6/ ,700 3, / ,900 4, US / ,000 2, /1999 9,700 1, US / ,000 2, / ,600 1, US / ,700 3, / ,700 3, I / ,000 4, /1998 6,000 2, LA /2000 5, /2000 5, US / ,500 2, / ,500 2, US /2000 9,300 1, /2002 7,800 1, US / ,500 7, / ,500 7, US /1999 8,500 1, /1999 8,300 1, LA /2000 1, /2000 1, LA / ,300 2, / ,500 4, LA / ,250 16, / ,250 16, I / ,100 15, / ,100 15, I / ,600 6, / ,200 8, LA 24 Louisiana specifications for sawing and sealing of HMA overlays requires that sawcuts be made at all transverse and longitudinal joints in the PCC pavement (9). Locations of the joints should be marked by placing a hub with a tack even with the ground at each edge of the shoulder. A PCC joint spacing of 6.1 m is typically used in the state. Joints are cut to a minimum of 3 mm wide by 25 mm deep; the sawing process should be completed within 3 days of the placement of the overlay. Only hot-poured rubberized asphalt-based sealants that comply with ASTM D 6690, Type II, are used in the sealing operation. In the event of transverse, longitudinal, or corner cracking in the underlying PCC slabs, full-depth patching is used to correct deficient locations prior to the HMA overlay. DATA COLLECTION Pavement performance data were obtained from the LADOTD pavement management system for the period ranging from 1995 to The PMS data are based on pavement condition measurements that are collected once every two years using the Automatic Road Analyzer (ARAN ) system that provides a continuous assessment of the road network. Conditions of the

8 Elseifi, Bandaru, Zhang, and Ismail 8 pavement are assessed using cracking, rutting, roughness, and patching. In addition, video crack surveys are collected once every two years and are available for each state highway in Louisiana. Collected data are reported every 1/10 th of a mile and are analyzed to calculate a Pavement Condition Index (PCI) on a scale from zero to 100. The PCI varies from 95 to 100, 85 to 94, 65 to 84, 50 to 64, and 49 or less for very good, good, fair, poor, and very poor roads, respectively. A number of threshold values are also used to trigger a specific course of maintenance and rehabilitation (M&R) actions (10). For composite pavements, the PCI is calculated as follows: PCI = MAX (MIN (RNDM, ALCR, PTCH, RUFF, RUT), {AVG (RNDM, ALCR, PTCH, RUFF, RUT) 0.85 STD (RNDM, ALCR, PTCH, RUFF, RUT}) (1) where, RNDM = random cracking index; ALCR = alligator cracking index; PTCH = patch index; RUFF = roughness index; RUT = rutting index; and STD = standard deviation. To determine the cracking pattern in the vicinity of the sawed and sealed joints, video crack surveys were reviewed using the VisiData TM software developed by Roadware, Inc. This software links video pavement imaging with global positioning and performance data as shown in Figure 2. Sawed and Sealed Joints FIGURE 2 Pavement Imaging and Joint Spacing (Site 6) Figure 3 illustrates the variation of the PCI for Site 1 (with and without the saw and seal method) throughout the monitored period. The data shown in these figures start on the collection cycle right after rehabilitation until the performance indices calculated in Similar plots were generated for all evaluated sites. It is noted that most of the sites did not experience a sharp drop in PCI rating from the time of rehabilitation, which is indicative that the original PCC pavements were stable. Using the fitted models shown in this figure, the service lives of the different sections for the PCI to drop to a terminal threshold was estimated by setting PCI to 69 or 75 (depending on the road classification) and predicting the number of years to reach this terminal condition.

9 Elseifi, Bandaru, Zhang, and Ismail 9 Pavement Condition Index (PCI - %) Treated Section Untreated Section y = x x R² = 0.82 y = x x R² = Service Life (years) FIGURE 3 Variation of the Pavement Condition Index during the Monitored Period for Site 1 Cost data for the saw and seal method as well as for the HMA overlays were obtained from actual bid items for each project. Figure 4 presents the percentage increase in the cost of the HMA overlay due to the saw and seal method. The increase in cost ranged from 0.5 to 21% with an average of 10% of the cost of the HMA overlay. The fluctuation in the cost of the saw and seal method as a percentage of the cost of the HMA overlay is mainly due to the variation observed in the quantity of HMA installed on each project. % I n c r e a s e C o s t i n Site ID FIGURE 4 Increases in Cost of the HMA Overlay Due to the Saw and Seal Method To avoid making unnecessary assumptions in the economic analysis with respect to future rehabilitation strategies and user costs, a simplified approach was adopted in this study. In this approach, the service life of each of the sites was determined for the PCI to drop to a terminal threshold (PCI T = 75 or 69 depending on road classification). The total cost of the rehabilitation strategy obtained from bid items was then divided by the predicted service life and the length of the section in order to determine the annual cost of the treatment per km based on the following equation:

10 Elseifi, Bandaru, Zhang, and Ismail 10 TAC= (2) where, TAC = Total Annual Cost per km; Rehabilitation Cost = total cost of rehabilitation; and N = predicted service life in years. Inflation factors were used to shift the costs associated with construction to the most recent year for the treated and untreated sections. By comparing the inflated TAC of the treated segment to the TAC of the untreated segment, one may assess the cost effectiveness of the treatment. Limitations of this approach are that it does not consider routine maintenance activities such as maintenance of the joints and cracks during the overlay service life and it assumes that user costs are the same for the treated and untreated segments. These assumptions were deemed acceptable for the state of Louisiana given prevailing maintenance practices. RESULTS AND ANALYSIS Predicted Service Life of Pavements Using the approach previously presented in Figure 3, the service lives of the pavement sections until the terminal pavement condition index is reached were calculated. Table 2 illustrates the predicted service lives for the treated and untreated sections. In order to identify the general trends in the results presented in this table, Figure 5 categorizes the level of improvement or disimprovement in the pavement service life due to the saw and seal method into a structured histogram. In this figure, individual sites were grouped together in classes that exhibit similar level of contribution from the saw and seal method. As shown by these results, 87% of the sites showed a positive improvement ranging from 1 to 12 years while the remaining 13% of the sites showed negative contribution due to the treatment. About 40% of the sections showed an improvement from 1 to 3 years and around 47% of the evaluated sections showed an improvement from 4 to 12 years. The average level of improvement to the pavement service life was 4 years. % of Sections 100% 90% 80% 70% 60% 50% 40% 30% 20% 10% 0% FIGURE 5 -ve Level of Improvement (Years) +ve % of Sections 50% 45% 40% 35% 30% 25% 20% 15% 10% 5% 0% < > 3 Predicted Service life difference between treated and untreated sections, Years (a) (b) Contribution of the Saw and Seal method to the Predicted Pavement Service Lives

11 Elseifi, Bandaru, Zhang, and Ismail 11 TABLE 2 Predicted Service Lives for the Evaluated Sections Site ID Predicted Service Life Treated Section Untreated Section Difference (years) Trigger Value Secondary Cracking Success of the saw and seal method mainly depends on applying the treatment at the exact locations of the joints. Past research studies noted that a saw cut more than 25 mm away from the joint would result in secondary cracking (8). The percentage of secondary cracks was determined by examining the cracking pattern in the video crack survey at each joint location, Figure 6. The frequency of appearance of secondary cracking was linked to the success of the treatment in extending pavement service life as reported in Table 2. It was determined that the percentage of secondary cracks in the sites in which the saw and seal method did not perform well or similar to the untreated sections was 0.6%. On the other hand, the average percentage of secondary cracks in the sites, in which the saw and seal method outperformed the untreated sections, was 0.5%. This low level of secondary cracks in the evaluated sites indicates that the approach adopted in Louisiana to locate the joints after placement of the overlay is effective in minimizing secondary cracks. Traffic Analysis The effect of traffic levels on the effectiveness of the saw and seal method was investigated. Figure 7 categorized the average level of improvements in the pavement service life as depicted in Table 3 for three levels of traffic: low (AADT less than 7,000), medium (AADT from 7,000 to 14,000), and high (AADT greater than 14,000). These definitions of low, medium, and high traffic levels are based on LADOTD design practices. As shown in this figure, it appears that the saw and seal method was more effective for low and medium traffic levels as compared to high traffic levels. In fact, the two sites in which the untreated sections outperformed the treated sections are in the high traffic category. One possible reason for this trend is that the increase in traffic loading may result in minor rutting in the wheel paths, which may cause the sealant to

12 Elseifi, Bandaru, Zhang, and Ismail 12 come off with time and, therefore, gradually decrease the serviceability of the pavement structure. Secondary crack Sawed and Sealed Joint (a) Sealant might be lost with time due to minor rutting Sealant in good conditions on shoulders and off the wheel paths (b) FIGURE 6 (a) Dislocated Joints and Double Cracking (Site 6) and (b) Sealant Condition under High Traffic Loading (Site 13)

13 Elseifi, Bandaru, Zhang, and Ismail 13 Average Improvement (Years) Low Medium High Traffic FIGURE 7 Effects of Traffic Levels on Performance of Saw and Seal Method Cost Effectiveness Figure 8 compares the cost of regular HMA overlays to the cost of treated HMA overlays based on the Total Annual Cost (TAC) concept presented in Equation (2). In this figure, a positive cost difference indicates that the use of the saw and seal method is economical while a negative cost difference indicates that the treatment method is not cost-effective as compared to regular HMA overlays. As shown in this figure, the majority of the sections (80%) indicate that the saw and seal method is cost-effective as compared to regular HMA overlays. Based on these results, it is concluded that the use of this treatment method is cost-effective as compared to regular HMA overlays. This treatment method appears more cost-effective for low to medium traffic volumes. % o f S e c t i o n s ve Difference in Cost between Untreated and Sawed and Sealed Sections -ve FIGURE 8 Cost Effectiveness of the Saw and Seal Treatment Method

14 Elseifi, Bandaru, Zhang, and Ismail 14 THEORETICAL INVESTIGATION The mechanism through which the saw and seal method is contributing to rehabilitated pavements was investigated using a Two-Dimensional (2D) Finite Element (FE) approach. Figure 9 presents the general layout of the FE model; in total, 7,168 elements were used to simulate the pavement structure. The horizontal dimension of the modeled portion was 2260 mm. The FE model simulated an HMA overlay with a thickness of 75 mm on top of a 250 mm concrete layer. The criticality of the stress field associated with the opening (Mode I) and shearing (Mode II) modes of loading was simulated by considering a jointed concrete layer, which is subjected to thermal horizontal movement and to traffic loading. Thermal movement was simulated by imposing a horizontal slab movement of 0.1 mm/sec on the concrete layer. A single tire applying a load of 40 kn on the pavement structure over an equivalent rectangular area was simulated with a uniform pressure of 724 kpa. To investigate the effectiveness of the saw and seal method, two models were simulated: one incorporating the saw and seal method in the construction of the overlay, and a control with the overlay applied directly to the concrete layer. While the sealant material, concrete layer, and dowel bar were assumed to respond elastically to the load (E sealant = 20MPa, E concrete = 27,580MPa, E steel = 200,000MPa), the HMA overlay was simulated as a viscoelastic material using a Generalized Kelvin model (11). The viscoelastic model consists of a spring and n-kelvin elements connected in series with the following Prony series coefficients: τ i = 0.001, 0.01, 0.1, 1, 10, 100, 1000, 10000, 1x10 5, 1x10 6, 1x10 7 and g i = 0.791, 0.676, 0.526, 0.356, 0.2, , , , , , and where τi s are the relaxation times and g i s are material constants referred to as relaxation strengths. As part of the viscoelastic definition of HMA, the initial instantaneous modulus was assumed to be 3450 MPa in order to define the elastic component of HMA. HMA Overlay Wheel load Sealant Thermal movement FIGURE 9 General Layout of the FE Model Dowel bar Figures 10 (a and b) illustrate the distributions of transverse strain and shear strain through the depth of the overlay at the PCC joint with and without the saw and seal method. Similarly, Figures 10 (c and d) illustrate the distribution of transverse strain and shear strain through the depth of the overlay at 430mm from the PCC joint; this was the transverse location away from the joint with the maximum strain responses in the overlay. As shown in these figures, the use of the saw and seal method significantly reduced the strain levels at the PCC joint associated with

15 Elseifi, Bandaru, Zhang, and Ismail 15 Mode I loading (Figure 10a) and Mode II loading (Figure 10b). The high strain levels at the bottom of the HMA overlay constructed without the saw and seal method will result in crack initiation at the bottom of the overlay and crack propagation with load repetitions. The transverse and shear strain distributions away from the joint were similar with and without saw and seal while being slightly greater when saw and seal was used. It is determined from these results that the constructed joints in the HMA overlay allow it to move with the underlying layer and to dissipate the energy generated due to expansion and contraction in the concrete layer and wheel loading without cracking. -8.0E E E E E E-03 0 Transverse Strain D e p t h ( m m ) Sawed and Sealed Overlay at the Joint Regular Overlay at the Joint 80 (a) 0 Shear Strain -4.00E E E E E-04 D e p t h ( m m ) Sawed and Sealed Overlay at the Joint Regular Overlay at the Joint 80 (b)

16 Elseifi, Bandaru, Zhang, and Ismail 16 Transverse Strain 0.00E E E E E E E E D e p t h ( m m ) (c) Shear Strain Regular Overlay Away from the Joint Sawed and Sealed Overlay Away from the Joint 0.00E E E E E E E E-06 D e p t h ( m m ) Sawed and Sealed Overlay Away from the Joint Regular Overlay Away from the Joint 80 (d) FIGURE 10 Horizontal and Shear Strain Distributions in the HMA Overlay with and without the Saw and Seal Method at the Joint (a and b) and Away from Joint (c and d) SUMMARY AND CONCLUSIONS The objective of this paper was to evaluate the performance of pavement sections built with the saw and seal method and to assess the cost-effectiveness of the treatment. To achieve this objective, the performance of 15 different sites that were constructed with the saw and seal method was monitored for a period ranging from 6 to 14 years and was compared to the performance of untreated sections. Based on the results of this analysis, the following conclusions may be drawn: The majority of the sites showed a positive improvement due to the use of the saw and seal method. 40% of the sections showed an improvement from 1 to 3 years and 47% of the evaluated sections showed an improvement from 4 to 12 years. The average level of

17 Elseifi, Bandaru, Zhang, and Ismail 17 improvement to the pavement service life due to the use of the saw and seal method was 4 years. The vast majority of the sections (80%) indicate that the saw and seal method is costeffective as compared to regular HMA overlays. This treatment method was more effective in sections with low to medium traffic volumes. Finite element results indicate that the constructed joints in the HMA overlay allow it to move with the underlying layer and to dissipate the energy generated due to expansion and contraction in the concrete layer and wheel loading without cracking. ACKNOWLEDGEMENTS The financial support provided by the Louisiana Transportation Research Center (LTRC) is greatly appreciated. The contents of this paper do not necessarily reflect the official views or policies of the Louisiana Department of Transportation and Development or the Louisiana Transportation Research Center. The authors would like to acknowledge the assistance of Ashley Horne and Christophe Fillastre of LADOTD. REFERENCES 1. Chen, H. J., and D. A. Frederick. Interlayers on flexible pavements. Transportation Research Record 1374, Transportation Research Board, Washington, D.C., Barksdale, R. D., S. F. Brown, and F. Chan. Potential benefits of geosynthetics in flexible pavements, NCHRP Report 315, Transportation Research Board, Washington, D.C., Johnson, A. M. Best Practices Handbook on Asphalt Pavement Maintenance. Report No. MN/RC , Minnesota Department of Transportation M. Marquart. Evaluation of Saw and Seal over the Overlaid Existing Concrete Joints. Final Report, Project NH-3-002(040)212, North Dakota Department of Transportation Deborah A. C., R. Cheng, R. J. Eger., L. Grusczynski., J. Marlowe., A. Roohanirad, and H. Titi. Highway Preventive Maintenance Implementation: Comparing Challenges, Processes and Solutions in Three States. Paper presented at the 83 rd Transportation Research Board Annual Meeting, Washington, D.C., Al-Qadi, I. L., E. H. Fini, M. A. Elseifi, J-F. Masson, and K. M. McGhee. Viscosity Determination of Hot-Poured Bituminous Sealants. Journal of the Transportation Research Board 1958, National Research Council, Washington, D.C., 2006, Jagannath, M., H. L. Von Quintus, and J. Farina. Reflection Cracking Related Observations, Modeling and Mitigation on New York City Composite Pavements. Journal of the Transportation Research Board 2084, Washington, D.C., 2008, Walter, P. K., and R. A. Bionda. Sawing and Sealing of Joints in Asphaltic Concrete Overlays. Transportation Research Record 1268, Transportation Research Board, Washington, D.C., 1990, Louisiana Department of Transportation and Development, Louisiana Standard Specifications for Roads and Bridges, 2006 Edition. 10. Khattak, M. J., G. Y. Baladi, G.Y., Z. Zhang, and S. Ismail. A Review of the Pavement Management System of State of Louisiana Phase I. Transportation Research Record: Journal of the Transportation Research Board, 2084, Washington, D.C., Al-Qadi, I. L, M. A. Elseifi, P. J. Yoo, S. H. Dessouky, N. Gibson, T. Harman, J. D Angelo, and K. Petros. Accuracy of Current Complex Modulus Selection Procedure from Vehicular

18 Elseifi, Bandaru, Zhang, and Ismail 18 Load Pulse in NCHRP 1-37A Mechanistic-Empirical Pavement Design Guide. Journal of the Transportation Research Board, 2087, Washington, D.C., 2008,