Cold In-place Recycling Research Articles

Effects of Ground Coal Bottom Ash and Calcium Chloride on the Compaction Properties of Cement Stabilized Cold In-Place Recycling (CIPR) Pavement Base Course

Effects of Ground Coal Bottom Ash and Calcium Chloride on the Compaction Properties of Cement Stabilized Cold In-Place Recycling (CIPR) Pavement Base Course

Evaluating dynamic modulus of cold in-place recycling mixture with foamed bitumen using field core samples

This study evaluates the dynamic modulus of Cold In-Place Recycling with Foamed Bitumen (FB-CIR) pavements, focusing on the influence of various recycled materials—reclaimed asphalt pavement (RAP), reclaimed inorganic binder stabilized aggregate (RAI), and their combination (RAP+RAI). Core samples from three representative FB-CIR projects in China were tested using the MTS-130 system across temperatures of −10°C, 5°C, 20°C, 35°C, and 50°C, and frequencies ranging from 25 Hz to 0.1 Hz. Statistical analysis and the Sigmoidal model were employed to analyze the viscoelastic behavior and establish the master curve for the FB-CIR dynamic modulus. The dynamic modulus of the three FB-CIR mixtures showed pronounced frequency-dependence, decreasing with reduced frequencies, and exhibited temperature sensitivity, with lower values at elevated temperatures. FB-RAI consistently demonstrated higher modulus values due to the hydration of previously unhydrated cement particles, while FB-RAP and FB-RAP+RAI displayed lower values, as RAP behaves similarly to unbound granular material. The construction of the master curve, based on the time-temperature superposition principle, enhanced our understanding of FB-CIR mixtures' mechanical behavior and enabled accurate extrapolation of dynamic modulus values across diverse conditions. Furthermore, FB-RAI's narrow phase angle variation indicates its superior mechanical stability and reduced sensitivity to external changes, making it ideal for areas with extreme climate fluctuations or heavy traffic. The study also identified three distinct phase angle variation patterns in FB-CIR mixtures, underscoring the importance of nuanced pavement design strategies that consider temperature, frequency, and material composition to optimize the performance and durability of FB-CIR pavements.

The use of asphalt waste dust for stabilization of sustainable pavement recycling

The asphalt waste dust as a sustainable material for stabilizing pavement recycling, which is cold in-place recycling (consists of reclaimed asphalt pavement, crushed rock aggregate base, and ordinary Portland cement), was presented in this study. To understand the effect of asphalt waste dust on stabilizing pavement recycling, 10–30 wt% asphalt waste dust was added and compared with the behavior of pure old-asphalt pavement material and old-asphalt pavement material mixed with 3.5 % OPC. The compaction test, unconfined compressive strength test (UCS), indirect tensile strength tests (IDT), and scanning electron microscope analysis were conducted under various mixing conditions. The addition of asphalt waste dust up to 20 wt% achieved desirable results of UCS and IDT involved with microstructural development, which were beyond the standard requirements of the base course from the Department of Rural Roads and the Department of Highway. A maximum of 20 wt% asphalt waste dust can be utilized for practical use with pavement recycling in the base course.

A Comprehensive Review of Life Cycle Cost Assessment of Recycled Materials in Asphalt Pavements Rehabilitation

This paper provides a comprehensive review of the use of life cycle cost assessment (LCCA) and life cycle assessment (LCA) methods for evaluating the sustainability and costs of using recycled materials in asphalt pavement rehabilitation projects. The review begins with an introduction to pavement rehabilitation strategies and the importance of choosing techniques based on thorough engineering and economic analyses. It then explores the different types of recycled materials that can be utilized, including reclaimed asphalt pavement, recycled concrete aggregate, and recycled asphalt shingles, discussing the key characteristics and properties of these materials based on previous laboratory studies. The review also examines the various rehabilitation methods that employ recycled content, such as cold in-place recycling, hot in-place recycling, and full-depth reclamation, providing a detailed breakdown of the construction, maintenance, and rehabilitation costs considered in LCCA and analyzing the environmental benefits of recycled material usage through a review of LCA techniques and criteria like carbon footprint reduction, impacts on air and water quality, and considerations of technological factors. Software tools for conducting LCA are compared and challenges to advancing the adoption of recycled materials are reviewed along with directions for future research efforts. The unique contribution of this work is its holistic assessment of LCCA and LCA methodologies to inform the sustainable and cost-effective deployment of recycled materials in asphalt pavement rehabilitation, a topic of growing importance for transportation infrastructure management. In summary, this current work provides a valuable review of how LCCA and LCA methodologies can assess the sustainability and costs of employing recycled content in asphalt pavement rehabilitation projects.

Erosion Potential of Stabilized Support Layers for Concrete Pavements and Overlays

The performance of concrete pavements and overlays is highly dependent on the uniformity, durability, and stability of the underlying support layers. Erosion of support layers can lead to pavement distresses and a reduction in pavement life. A review of existing erodibility performance tests that assessed stabilized support layers was first conducted to identify and evaluate their suitability for adaptation. The Hamburg wheel tracking device (HWTD) test was selected to assess the erosion potential of asphalt and cement stabilized support layers. Field testing with distress surveys, falling weight deflectometer, and coring was completed to obtain HWTD specimens and link laboratory results to pavement performance. The HWTD test was performed on cores obtained from in-service cement and asphalt stabilized support layers, a cold in-place recycling (CIR) mixture, and cement stabilized laboratory mixtures. As expected, an increase in cement content within cement stabilized mixtures decreases the likelihood of erosion with the HWTD. Additionally, conventional asphalt stabilized base layers were highly erosion resistant. Erosion resistant cement stabilized bases (including full-depth reclamation) should target an average HWTD erosion depth ≤2 to 4 mm (0.08 to 0.16 in.) after 10,000 load cycles based on the functional classification and expected traffic volume of the pavement section. Likewise, asphalt stabilized bases (including CIR and support layers for concrete overlays) should target an average HWTD erosion depth ≤12.5 mm (0.5 in.) after 7,500 load cycles with performance grade 64 binder.

Laboratory evaluation and field demonstration of cold in-place recycling asphalt mixture in Michigan low-volume road

Cold-in place recycling (CIR) is a promising technology for the rehabilitation of asphalt pavements. However, the CIR asphalt pavement constructed in the field often has high air voids due to the presence of moisture during construction, and the moisture susceptibility of the pavement is crucial in determining its service life. Therefore, the objective of this research was to assess the laboratory performance of CIR asphalt mixes under freeze-thaw conditions (The mix prior to being subjected to freezing and thawing is labeled as "dry condition", while the mix that was placed in a refrigerator at –18 °C for 16 h and then transferred to a distilled water bath at 60 °C for 24 h is referred to as "post-freeze-thaw") and forecast in-situ pavement performance through pavement mechanistic-empirical design (PMED). Moisture susceptibility was evaluated by preparing CIR asphalt mixtures under dry condition and freeze-thaw conditions. The Disk-Shaped Compact Tension (DCT) test was utilized to approximate the low-temperature characteristics of the CIR mixture, while the rutting resistance properties were assessed using the Hamburg wheel tracking device (HWDT). The dynamic modulus test was used to assess the elastic deformation characteristics. The asphalt was extracted from the loose material, and the viscoelasticity properties were analyzed using the Dynamic Shear Rheometer (DSR) test and Asphalt Binder Cracking Device (ABCD) test, respectively. Based on the M-E inputs, the projected pavement deterioration was determined through calculations. The outcomes indicated that the dynamic modulus of the asphalt mixture after the freeze-thaw cycle dropped by 11–42 % under varying temperatures and frequencies. The number of wheel passes for the dry condition CIR asphalt mixture was 8.4 % higher than that of the post-freeze-thaw CIR asphalt mixture. The fracture energy dropped by 6 % after freeze-thaw conditions. The emulsion asphalt used in the RAP (reclaimed asphalt pavement) made the binder softer, the fatigue and low-temperature cracking resistance of the material was enhanced, and decreased its resistance to rutting. the results of the M-E pavement design demonstrated that the freeze-thaw condition increased rutting, cracking, and IRI (International Roughness Index) distress. In conclusion, the application of CIR technology in the project enhanced the performance of the asphalt pavement with regard to its resistance to cracking and fatigue. As a result, CIR pavement may be suitable for use in low-traffic road.

Comparative analysis of cold in-place recycling for roadway maintenance and rehabilitation from the perspectives of technical-cost-environmental nexus

Cold-in-place recycling (CIR) is a sustainable road pavement maintenance technology for its on-site operation and complete reuse of reclaimed asphalt pavement. However, its sustainable performance has not been thoroughly investigated. This study aims to systematically assess and compare CIR against three alternative maintenance technologies from technical, cost and environmental perspectives, specially taking into account different numbers of repaired layers. The technical improvement in full-depth loading resistance is evaluated using a newly developed multi-sequenced repeated load (MSRL) test. Environmental impacts are assessed through life cycle assessment (LCA), while cost analysis is conducted using life cycle cost analysis (LCCA), with consistent system boundary applied. Additionally, a nexus analysis is performed using a modified Boston Consulting Group (BCG) matrix to comprehensively examine the sustainable performance of different treatments and further explore the synergies and trade-offs among various assessment aspects. The multi-dimensional sustainable assessment results reveal the influence factors in each perspective. Final BCG matrix shows that CIR can achieve the comparable technical performance to the conventional maintenance treatment, while reducing GHG emissions by 60.8% and cost by 45.8%. The methodology and findings of this study are expected to provide helpful insights for decision-makers in reducing negative impacts and promoting integrated management for sustainability.

Characterization of the Cracking Resistance Gradient of Bitumen Emulsion-Based Cold In-Place Recycling Mixtures over Curing by Semi-Circular Bending Test

To better reveal the performance development of bitumen emulsion-based cold in-place recycling (BE-CIR) mixture over curing, a semi-sealed laboratory curing method was proposed in this research to simulate the in situ moisture evaporation process and cracking resistance of the BE-CIR specimen at different depths during a curing time of 28 days, which was also investigated by the semi-circular bending (SCB) test. The influencing factors of cement content (1.5% to 2.5%), initial moisture content (3.5% to 4.5%), curing temperature (25 °C to 45 °C) and relative humidity were investigated, and the significance of different factors affecting the performance development was also analyzed. The results indicate significant variations in cracking performance parameters at different depths, with the top part exhibiting notably higher tensile strength and fracture energy compared to the bottom part, and a gradient index (GI) is proposed to describe the difference. Cement content affected early tensile strength and fracture energy, while the initial moisture content affected the development rate of the performance. The influence of curing temperature was extensive, and as the temperature increased beyond 40 °C, the strength of the effect decreased. High humidity during the early stage of curing inhibited the strength formation and development of fracture energy. The performance development of the BE-CIR mixture is more significantly influenced by the moisture migration process, which is governed by curing temperature and relative humidity, as opposed to the cement content and initial moisture content.

Drying behavior modeling of bitumen emulsion-based cold in-place recycling pavement considering heat-moisture coupling effects

Bitumen Emulsion-based Cold In-place Recycling (BE-CIR) pavement has been widely applied for its energy-saving and environmental friendliness. BE-CIR is manufactured at ambient temperature and requires a specific drying duration to develop sufficient strength before overlay placement. However, it is challenging to characterize the drying behavior of BE-CIR pavement due to the complex field curing environments and strength formation process. Hence, this research aims to develop a drying behavior model of BE-CIR pavement considering the heat-moisture coupling effects, which can help optimize the timing for overlay placement under different curing environments. Numerical models of mixture and pavement were established based on the heat and mass transfer theories. Actual temperature and humidity data obtained from laboratory tests and field monitoring were used for model calibration and validation. Time-variable coefficient and depth correction coefficient developed based on functional relationships of physical parameters were proposed to calibrate the model. The finite element calculation results indicated that the calibrated model could effectively simulate the drying behavior of BE-CIR pavement under natural curing environments. Two typical working conditions based on natural pavement curing environments were simulated. The calculation results suggested that the curing time required to reach moisture equilibrium was 120 h at medium temperature and high humidity and 50 h at low temperature and medium humidity, both higher than the measured 30 h at high temperature and low humidity.

Quantifying the Workability of Cold In-Place Recycling in the Laboratory

Abstract The Dongre Workability Test (DWT) is a method for determining an asphalt pavement’s relative workability based on stress–strain relationships during compaction in a Superpave gyratory compactor. Although the DWT has seen favorable results with warm-mix and hot-mix asphalt, there has been limited attempts to apply it to cold-mix asphalt (CMA), and those limited attempts did not provide conclusive results. This research re-examined the curves developed during the DWT data collection in order to better quantify the workability of CMA, specifically, cold in-place recycling (CIR). Phase one consisted of defining ten possible metrics from the stress–strain curve and applying them to samples with three different curing conditions. From these preliminary results, the five metrics that showed the greatest differences between curing conditions with small relative coefficients of variation were chosen for continued evaluation. In phase two, these five metrics were applied to three different asphalt emulsions at four different curing conditions (temperature-minutes: 10C-30, 10C-120, 60C-30, and 60C-120). Two metrics based on different areas under the stress–strain curve yielded the most logical and consistent results, with higher values indicating a more workable mixture. Samples cured for 30 minutes at either 10°C or 60°C showed the most noticeable distinction between workability of each asphalt emulsion. Moving forward, it is recommended these metrics be applied to additional asphalt emulsions, reclaimed asphalt pavement sources and gradations, and curing conditions to determine if the DWT method can be modified for application to CIR mixtures.

Micropore structure characterization of the bitumen emulsion-based cold in-place recycling mixture considering water gradient migration condition through multiple XCT scanning

Bitumen Emulsion-based Cold In-place Recycling (BE-CIR) has been widely used all around the world due to its superior environmental benefits. Unlike the hot mix asphalt (HMA), BE-CIR mixture presents a unique moisture migration behavior after compaction. The migration of water can alter the micro-pore structure of the BE-CIR mixture and then change its mechanical performance. Therefore, it is essential to characterize the variation of internal structure, especially the air voids, in depth direction during the curing process of BE-CIR mixture. A one-way evaporation method was developed to simulate the field moisture migration of BE-CIR mixture specimens in laboratory. To track the internal structure change with time, multiple X-ray Computed Tomography (XCT) scanning examinations were performed on the lab-prepared specimens with three different curing periods (0 h, 60 h, and 153 h). The effects of curing temperature and initial moisture content on the micropore structure development were also investigated. The morphology variations of air voids including the content, number, volume distribution and void gradation in the depth direction with curing time were further characterized. The results indicate that there is a 0.5% difference in air void content between the top and bottom of the BE-CIR mixture. The BE-CIR mixture's micropore structure evolved over the course of curing with two key characteristics: a fast increase in the number of small voids and a sustained development of large voids. The development of more tiny pores and the gradient properties of these pores, which predominated during the curing time of 60 to 153 h, were a reflection of the internal migration of free water. The initial moisture content mainly affects the magnitude of the large void variation during the curing time of 0 to 60 h, while the curing temperature affects the proportion of pore increase between the two curing periods. The outcomes can provide a better understanding on the dynamic volumetric characteristics of the BE-CIR pavement over the curing process.

Evaluation of Curing Effects on Bitumen Emulsion-Based Cold In-Place Recycling Mixture Considering Field-Water Evaporation and Heat-Transfer Conditions

The strength growth of a bitumen emulsion-based cold in-place recycling asphalt mixture (BE-CIR) is time-dependent and time-consuming due to the addition of water. There is a great difference between the curing conditions of specification in the laboratory and the in situ conditions, which often leads to a great discrepancy between the results of lab specimens and the field cores. The main objective of this paper is to evaluate the curing effect on laboratory BE-CIR considering field-water evaporation and heat-transfer conditions. Four different curing methods were designed by using different combinations of waterproof layers, heat insulation layers, and variable temperature modes. The variations in temperature indexes, moisture content, air void, and indirect tensile strength (ITS) with curing time were tested, and the mutual influence of these indicators was analyzed. Furthermore, the results of the laboratory samples were compared with the field cores. Testing results show that the performance of the BE-CIR mixture is significantly different from that with no treatment, which is manifested as higher moisture content and lower air void and ITS under the same curing time. The internal temperature of the mixture is the main factor affecting the variation of moisture content, especially on the first curing day. The air void of the mixture has a strong linear relationship with the moisture content. Moisture content and ITS under different curing methods showed similar trends and could be divided into two stages. Taking the field cores as a benchmark, it can be concluded that the field-water evaporation condition should be considered in the setting of indoor curing methods, while the heat transfer could not.

Field Investigation of Long-Pin Shear and Short-Pin Raveling Tests on Cold in-Place Recycled Layers: Wisconsin's Share for the Enhancement of Cold in-Place Recycled Sustainability

Currently, Wisconsin, U.S., opens the cold in-place recycled (CIR) base layer to traffic 0 to 3 h after construction. The CIR layer is then paved—when the in situ moisture content drops to 2.5%—with hot mix asphalt. There is no quantitative measure for estimating the opening time to traffic, and, to determine the in situ moisture content, there is a need to obtain field samples and perform laboratory measurements. These methods are time-consuming, labor-intensive, or both. To overcome these shortcomings, the feasibility for use of quantitative and real-time evaluation techniques was investigated. Long-pin shear (LPS) and short-pin raveling (SPR) tests developed as a part of the National Corporate Highway Research Program 09-62 study were used for measuring the properties of the CIR layer (blow count and torque) over time. Regression models were developed from these tests using the in situ moisture content measured from field samples, which were then used for proposing threshold values in Wisconsin. The SPR and LPS test data enabled the establishment of correlations between the measured values. Statistical analysis revealed that the pavement temperature and curing time significantly influence the measured properties from the LPS and SPR tests.

Key Performance Analysis of Emulsified Asphalt Cold Recycling Mixtures of the Middle Layer of Pavement Structure.

In the maintenance engineering of asphalt pavement, it is often encountered that both the surface and middle layers are damaged and need to be maintained. The cold in-place recycling technology can be used to simultaneously treat multi-layer diseases and reduce the waste of pavement materials. The cold in-place recycling mixture is rarely used for high layer of pavement structure in high-grade highway. In the supporting practical engineering, the emulsified asphalt cold in-place recycling mixtures were paved as the middle layer of pavement structure by the laying of an overlay. In order to comprehensively evaluate the material performances, coring samples were drilled after cold recycling pavement opening to traffic, and different performance tests were carried out based on the coring samples. The newly paved SMA mixtures were set as the control group. The high temperature stability of cold recycling mixture was analyzed by dynamic creep test and MMLS3 accelerated loading test. Then, the cracking resistance of cold recycling mixture was studied by semi-circular bending test. Finally, the effect of curing time on splitting strength of cold recycling mixture was measured, and the moisture susceptibility was analyzed by dry-wet splitting test and freeze-thaw splitting test. The test results showed that the high temperature stability of cold recycling mixture was worse than SMA mixture. For the cold recycling mixture, the deformation value at the early stage and deformation rate at the stable stage were larger than SMA mixture in the accelerated loading process, and shear failure at high temperature occurred earlier. The cracking resistance of cold recycling mixture was worse than SMA mixture because of the aging effect of the old asphalt and adverse influence of the added cement binder. The effect of curing time on splitting strength of cold recycling mixture was significant, and two stable periods of early strength were, respectively, reached after curing 3 days and 7 days. The indexes of moisture susceptibility, including dry-wet splitting strength ratio and freeze-thaw splitting strength ratio, were obviously lower than that of SMA mixture, and the test values not up to the standard requirement existed. For the emulsified asphalt cold in-place recycling mixture, the improvement of material performances should be focused on, especially the moisture susceptibility. In the research, the emulsified asphalt cold in-place recycling mixtures were acceptably used as the middle layer of maintenance pavement structure. The reliable discussions were summarized based on coring samples collected from real-life road sections. The case can provide guidance and reference for similar engineering applications.

Investigation of the Commercial Potential of Emulsified Asphalt Cold In-Place Recycling Based on SWOT Analysis

Investigation of the Commercial Potential of Emulsified Asphalt Cold In-Place Recycling Based on SWOT Analysis

Optimum Fluid Content in Pavement Cold In-Place Recycling Containing Waste Materials

The planning of road infrastructure undergoes major changes, especially in terms of sustainable development. Recycling of pavement structures involves the reuse of materials from existing pavement structures due to its timesaving and environmental benefits, as well as cost reduction. According to the recycling temperature, recycling can be hot and cold. This paper deals with cold in-place recycling and the determination of the optimum fluid content for by-product materials in mixtures compared with one containing natural zeolite. The content of bitumen emulsion and cement—which are the most used materials so far in cold recycling along with foam bitumen—was replaced with fly ash, slag or natural zeolite, and bakelite, respectively, while recycled asphalt pavement from Serbia (Žabalj) was used. Six different mixtures were made. The mixture with the addition of fly ash had the highest optimum fluid content (7.6%) compared with all test mixtures. Mixtures with slag, natural zeolite, and bakelite were in the range of a mixture containing 2% cement. Furthermore, the mixture with 3% cement had the lowest optimum fluid content (5.7%) in comparison to all the mixtures that were tested.

Investigation of Polyurethane Modified Cold Bitumen for Fast Cold In-Place Recycling

Cold in-place recycling is gaining more attention worldwide because of its lower energy consumption, while the normally used asphalt emulsion and foamed asphalt cannot meet this requirement of short traffic disturbance and road performance of the surface layer. In this research, a polyurethane-modified cold binder (PMCB) was designed and investigated for the fast and high-quality cold in-place recycling of reclaimed asphalt. For the first step, functional group analysis and fluorescent microscopy were used to reveal the curing process and the modification mechanism of the PMCB. Then a series of rheological tests were used to comprehensively evaluate the viscoelastic properties of the PMCB at different curing stages. Finally, the mechanical performance of the PMCB mortar sample was evaluated with the monotonic tensile test and tensile fatigue test. The results indicated that the polymerization reaction in the PMCB consisted of three reactions, and the urethane/urea linkage led to the formation of the polymeric network. The polyurethane polymeric network led to a significant increase in the complex modulus and a decrease of the phase angle. The PMCB also exhibits suitable viscosity at environmental temperatures, good relaxation properties at low temperatures, and less temperature sensitivity. Compared to the base asphalt and styrene butadiene styrene polymer modified bitumen mortar samples, the PMCB mortar samples showed significant advantages in tensile strength, dissipation energy, and tensile fatigue properties. Furthermore, the polyurethane-modified cold asphalt mixture (PMCM) showed better indirect tensile strength than the porous asphalt mixture with fresh aggregate and fresh asphalt binder when the curing time of the PMCM reached 6 h.

Correlating field and laboratory evolution of curing in cold in-place recycled (CIR) materials

This study compared and explored the relationship between laboratory oven conditioning and field curing, using materials from six CIR projects and various field and laboratory testing procedures. The results indicate that the test methods considered in this study effectively tracked the curing process of laboratory and in-situ CIR materials. The data generated in the study provided good insight into the curing evolution of CIR materials and was employed to develop a robust relationship between the field and laboratory curing evolution times. Furthermore, the study introduced ground-penetrating radar (GPR) for continuous and repetitive monitoring of moisture content in CIR pavements.

Moisture migration of bitumen emulsion-based cold in-place recycling pavement after compaction: Real-time field measurement and laboratory investigation

Bitumen emulsion-based cold in-place recycling (BE-CIR) has gained in popularity due to its cost-effectiveness, energy saving and environmental friendliness. Unlike hot mix asphalt (HMA), BE-CIR is manufactured at room temperature and requires a longer curing time to allow for water evaporation. However, little attention has been given to the water migration process in BE-CIR pavement. Given the difficulty of simulating field curing conditions in laboratory, a series of on-site sensors were used to continually monitor the temperature and moisture gradient inside BE-CIR pavement at different depths after compaction. After one month of curing, field cores were drilled from the experimental road, and the volumetric properties and semi-circular bending strength of both top and bottom halves were studied. The obtained humidity index (HI) was used to quantify the relative moisture content in BE-CIR mixture. Testing results show that the moisture migration over time can be divided into two stages, with the first exhibiting a quick fall and the second exhibiting a minor downward tendency. During the curing phase, a unique gradient characteristic can be identified for the initial moisture distribution and moisture movement of the BE-CIR layer in the field. Both the temperature gradient and depth location can affect the water migration process significantly. Furthermore, the final moisture content, air void content and the semi-circular bending strength of field cores also present clear gradient characteristics, indicating the importance of the moisture gradient migration process on the long-term performance of the BE-CIR pavement.

Pavement Recycling in Cold Climates: Laboratory and Field Performance of the MnROAD Cold Recycling and Full Depth Reclamation Experiment

In 2019 a series of test sections were constructed on 70th Street in Albertville/Otsego, MN. The existing roadway was badly deteriorated with an international roughness index value above 300 in./mi, which places it in a “poor” performance category. A combination of treatments including cold in-place recycling (CIR), cold central plant recycling (CCPR), and full depth reclamation (FDR) stabilized with foamed or emulsified asphalt were used to evaluate performance in cold regions. Sections including a typical hot mix asphalt (HMA) mill and fill were also evaluated. All sections contained a 1-in. HMA thinlay as the wearing surface. This paper presents the laboratory testing data for the mixtures, including application of HMA tests not typically applied to CIR, CCPR, and FDR, the field performance to date, and a new approach to connecting laboratory data to field performance.