Pavement Rehabilitation Treatments Research Articles

Life-cycle assessment of climate change impact on time-dependent carbon-footprint of asphalt pavement

This study aims to quantify life-cycle carbon footprint of asphalt pavement due to warming temperatures under climate change scenario.Pavement Mechanistic-Empirical (ME) Design Method was used to simulate long-term pavement performance with historic and projected temperature inputs. Life-cycle assessment (LCA) was conducted to calculate CO2emissions in pavement life cycle including phases of raw materials, plant production, transportation, field construction, traffic delay, and use. In particular, time-dependency of CO2emission was considered with physical decay to increase the accuracy in estimating cumulative radiative forcing. It was found that warming temperatures would lead to faster structural deterioration of pavement, resulting in earlier or more frequent overlay treatments. Pavement rehabilitation treatments generate more CO2 emission in material and construction related stages but cause the reduction of CO2 emission in pavement use phase. The LCA results show that climate change causes greater CO2 emission abundance over the years during the study period.

Energy and environmental consequences of a cool pavement campaign

Raising the albedo (solar reflectance) of streets can lower outside air temperature, reduce building energy use, and improve air quality in cities. However, the production and installation of pavement maintenance and rehabilitation treatments with enhanced albedo (“cool” pavements) may entail more or less energy consumption and carbon emission than that of less-reflective treatments. We developed several case studies in which a cool surface treatment is substituted for a more typical treatment (that is, a cool technology is selected instead of a more typical technology). We then assessed over a 50-year analysis period the changes in primary energy demand (PED, excluding feedstock energy) and global warming potential (GWP, meaning carbon dioxide equivalent) in Los Angeles and Fresno, California. The analysis considers two stages of the pavement life cycle: materials and construction (MAC), comprising material production, transport, and construction; and use, scoped as the influence of pavement albedo on cooling, heating, and lighting energy consumption in buildings.In Los Angeles, substituting a styrene acrylate reflective coating or a chip seal for a slurry seal in routine maintenance, or a bonded concrete overlay on asphalt (BCOA) without supplementary cementitious materials (SCM) for mill-and-fill asphalt concrete in conventional or long-life rehabilitation, induced MAC-stage PED and GWP penalties that substantially exceeded use-stage savings, primarily due to material production. Modified rehabilitation cases in which SCM comprised 21% to 50% of the BCOA’s total cementitious content by mass (portland cement+SCM) yielded smaller total (MAC+use) PED and GWP penalties, or even total PED and GWP savings. Trends in Fresno were similar, with some differences in GWP outcomes that result from Fresno’s longer heating season.The modified rehabilitation cases using BCOA with high SCM content yielded total GWP savings in each city; all other cases yielded total GWP penalties. The magnitude of the one-time GWP offset offered by global cooling from the increased albedo itself always, and sometimes greatly, exceeded the 50-year total GWP penalty or savings.In Los Angeles, the annual building conditioning (cooling+heating) PED and energy cost savings intensities yielded by cool pavements were each about an order of magnitude smaller than the corresponding savings from cool roofs.

Multidimensional benefit–cost evaluation of asphaltic concrete overlays of rigid pavements

Using the data from a national study in the USA, this study demonstrated a comprehensive and multidimensional pavement treatment evaluation methodology and used the methodology to evaluate the short-term and life cycle cost-effectiveness (CE) of five rigid pavement rehabilitation treatments. Four measures of effectiveness were used in this study: the sudden decrease in surface roughness, treatment service life, increase in average pavement condition over the service life and the area bounded by the performance curve. This study established relationships that quantify the influence of pre-treatment condition on treatment effectiveness. Also, the models were developed to describe the treatment effectiveness as a function of traffic loading and climatic severity. It is seen that at high traffic loading, there is relatively little difference in treatment effectiveness across various climate severities. This study suggests that superior effectiveness of a treatment does not necessarily translate into superior CE. Also, the treatment location was found to influence the relative effectiveness of the treatments. Overall, the results suggest that treatment ‘crack-and-seat and 8-in. asphalt concrete overlay’ is the most cost-effective.

Random Parameters Seemingly Unrelated Equations Approach to the Postrehabilitation Performance of Pavements

Pavement rehabilitation is one of the most critical and costly forms of infrastructure asset management. Yet determining the subsequent performance of rehabilitated pavements is a complex task, particularly when multiple performance measures such as roughness, surface deformation, and structural integrity are considered. The complexity arises in part because of the interrelation among these performance measures and the fact that data relating to factors known to affect these measures may not be available. This paper seeks to demonstrate an appropriate methodological approach for studying the postrehabilitation performance of pavements using data from rural interstate roads in Indiana. Specifically, a random parameters seemingly unrelated equations approach is applied to explicitly account for the cross-equation correlation that exists among pavement-performance measures and the underlying heterogeneity across observations caused by imperfect data. The results provide some new insights into the interrelationships among the pavement rehabilitation treatments considered, pavement performance, traffic loads and trucks, weather and soil conditions, and rehabilitation expenditures.

An analysis of the cost-effectiveness of rigid pavement rehabilitation treatments

This paper analyses the costs, effectiveness, and cost-effectiveness of three standard rehabilitation treatments of rigid pavements using historical data from the state of Indiana. Treatments investigated are Hot Mix Asphalt (HMA) Overlay, Patching, and Portland Cement Concrete (PCC) Overlay. Performance criteria used are the sudden decrease in surface roughness after treatment, treatment service life, and increase in average pavement condition over the service life. Cost-effectiveness is the ratio of treatment effectiveness to treatment cost. Results suggest that Patching and PCC Overlay treatments are the most effective on the basis of short term and long term effectiveness, respectively. The results also show that at relatively small levels of traffic loading, a change in climatic severity has greater influence on treatment effectiveness than that at higher levels of traffic loading. On the basis of cost-effectiveness, the results suggest that PCC Patching appears to be the best treatment.

Aggregate and disaggregate statistical evaluation of the performance-based effectiveness of long-term pavement performance specific pavement study-5 (LTPP SPS-5) flexible pavement rehabilitation treatments

Engineers continually seek effective techniques for preserving highway infrastructure. Using data from the specific pavement study#5 of the long-term pavement performance (LTPP) programme's western region, this article evaluated the performance of eight flexible pavement rehabilitation treatments. Aggregate and disaggregate post-treatment performance models were developed for each treatment. Effectiveness was measured in the short term (roughness reduction) and long term (estimated treatment service life and area bounded by the performance curve (ABP)). The results showed that compared to 2-inch treatments, 5-inch treatments were on average more effective in terms of the following measures: 47% (estimated service life) and 35% (ABP) depending on the level of surface preparation, mix type and initial pavement condition. Also, relative to minimal surface preparation, intensive surface preparation generally yielded greater effectiveness: 25% (estimated service life) and 49% (ABP) depending on added thickness, mix type and initial pavement condition. Compared to recycled mix treatments, virgin mix was marginally more effective. Finally, compared to pavements treated in poor condition, those treated in good condition were significantly more effective. Treatment effectiveness models were developed for predicting the expected effectiveness of future treatments on the basis of attributes such as treatment type, added layer thickness, level of surface preparation and mix type.

Evaluating the Cost Effectiveness of Flexible Rehabilitation Treatments Using Different Performance Criteria

At a certain point in the life of a flexible pavement, rehabilitation is required to improve pavement condition and to defer reconstruction. Pavement managers seek the best rehabilitation treatment on the basis of cost effectiveness. Using 1994–2002 data from a wet-freeze mid-Western state in the United States, this paper analyzes the cost effectiveness of four flexible pavement rehabilitation treatments: functional hot-mix asphalt (HMA) overlay, structural HMA overlay, resurfacing (partial 3R standards), and mill full-depth and asphaltic concrete overlay. The performance indicator used is the international roughness index and treatment effectiveness is measured in terms of performance jump (short-term), and service life and increase in pavement performance (long-term). The treatment cost is the equivalent uniform annual cost per lane-km incurred by the agency and user; and cost effectiveness is the ratio of effectiveness to cost. The study estimated treatment effectiveness under various combinations of traffic loading and climatic condition, and initial pavement condition. The results suggest that in the short-term, HMA structural overlay is the most effective treatment. For the long-term, the results are equivocal: HMA structural overlay is most effective from the perspective of average performance over the treatment life; resurfacing (partial 3R standards) is the most effective from the perspective of treatment service life. With regard to cost effectiveness, however, the results were consistent: for all three measures of treatment effectiveness, mill full-depth and asphaltic concrete overlay unequivocally appears to be the most cost effective treatment. Finally, the paper recommends that cost effectiveness analysis should be accompanied by a candid deliberation of project constraints, the local environment, and agency practices.

Comparison of Methods for Evaluating Pavement Interventions

Decision makers are always faced with the challenge of selecting and implementing cost-effective pavement preservation alternatives, particularly when encountering shrinking budgets and increased competition for funds. Pavement intervention and investment evaluation criteria used in past research and practice are reviewed. The synthesis of pavement preservation effectiveness and efficiency evaluation techniques that is presented is unique from both benefit and cost perspectives. Criteria are of the following categories: effectiveness (benefit) only, cost only, cost-effectiveness, and economic efficiency. Computational details, past applications, merits, and demerits of various evaluation criteria are discussed for each criterion. Then selected criteria are computed with data from a national pavement study; they are used to evaluate alternative rigid pavement rehabilitation treatments. The case study results suggest that the superior short-term effectiveness exhibited by a treatment does not necessarily translate into superior long-term effectiveness. The evaluation results can vary widely for cost only, effectiveness only, and both cost and effectiveness criteria. Thus, evaluation based on cost-only or effectiveness-only criteria can yield biased evaluation results. To be a suitable candidate, a treatment or strategy must be not only effective but also cost-effective and economically efficient and the incorporation of user costs into evaluation can significantly influence the evaluation results. Such a synthesis can be a vital support for highway agencies in decision making for infrastructure management in general and pavement management in particular.

Fuzzy Logic Pavement Maintenance and Rehabilitation Triggering Approach for Probabilistic Life-Cycle Cost Analysis

Life-cycle cost analysis (LCCA) is an important tool in transportation asset management. Transportation agencies have used both deterministic and probabilistic LCCA approaches. Probabilistic approaches allow decision makers to evaluate the risk of an investment by using uncertain input variables, assumptions, or estimates. The incorporation of fuzzy logic–based models into the risk analysis process is explored to enhance further the traditional probabilistic LCCA method. It proposes a fuzzy logic approach for determining the timing of pavement maintenance, rehabilitation, and reconstruction (MR&R) treatments in a probabilistic LCCA model for selecting pavement MR&R strategies. Instead of using predefined service life for initial construction and future rehabilitations, the proposed approach uses performance curves and fuzzy logic triggering models to determine the most effective timing of MR&R activities. The new approach is compared with the deterministic and traditional probabilistic approaches in a simple case study. The case study demonstrates that the fuzzy logic–based risk analysis model for LCCA can effectively produce results that are at least comparable to those of the benchmark methods while effectively considering some of the uncertainty inherent to the process.

Performance of Rigid Pavement Rehabilitation Treatments in the Long-Term Pavement Performance SPS-6 Experiment

The results of a study conducted to assess the relative performance of different jointed rigid pavement rehabilitation treatments, including the influence of pretreatment condition and other factors, are presented. The data used in the study were drawn from the Long-Term Pavement Performance Studies' Specific Pavement Study (SPS) SPS-6 and General Pavement Study (GPS) GPS-7B experiments. The rehabilitation treatments used in the SPS-6 experiment were minimal and intensive nonoverlay repair, 4-in. asphalt overlays with minimal and intensive preoverlay preparation, 4-in. overlays with sawed and sealed joints, and 4- and 8-in. asphalt overlays of cracked and seated concrete slabs. Overall, the rigid pavement rehabilitation treatments in the SPS-6 experiment could be ranked from most to least effective in the following order: 8-in. overlay of cracked or broken and seated pavement, 4-in. overlay (of either intact or cracked or broken and seated pavement, with or without sawing and sealing of joints and with either minimal or intensive preoverlay repair), concrete pavement restoration with diamond grinding, and concrete pavement restoration without diamond grinding. Concrete pavement restoration with diamond grinding yielded an initial posttreatment international roughness index (IRI) of 1.05 m/km, on average, whereas restoration without diamond grinding yielded no benefit in IRI and in fact tended to leave the pavement rougher than before. In the long term, both restoration and overlay treatments reduced long-term roughness, rutting, and cracking levels compared with those on the control sections, but the conditions of the restored test sections are approaching those of the control sections faster than those of the overlay sections.

Performance of Flexible Pavement Rehabilitation Treatments in the Long-Term Pavement Performance SPS-5 Experiment

The results of a study conducted to assess the relative performance of different flexible pavement rehabilitation treatments, including the influence of pretreatment condition and other factors, are presented. The data used in the study were drawn from the Long-Term Pavement Performance Studies' Specific Pavement Study (SPS) SPS-5 and General Pavement Study (GPS) GPS-6B experiments. The rehabilitation treatments used in the SPS-5 experiment are 2- and 5-in. overlays with virgin or recycled asphalt concrete mixes with or without preoverlay milling. Overlay thickness and preoverlay roughness levels were the two factors that most influenced the performance of the asphalt overlays of asphalt pavements in the SPS-5 experiment with respect to roughness, rutting, and fatigue cracking. Over the long term, the 5-in. overlays outperformed the 2-in. overlays with respect to roughness, rutting, and fatigue cracking. Overlay mix type (virgin versus recycled) and preoverlay preparation (with or without milling) had slight and inconsistent effects. The average initial postoverlay international roughness index of an asphalt overlay of an asphalt pavement was found to be 0.98 m/km. The data show a slight but statistically significant tendency for asphalt pavements overlaid when they were rougher to have more initial roughness after overlay than asphalt pavements overlaid when they were smoother. The data show that, on average, about 6 mm of rutting develops in the first year or so after placement of an asphalt overlay of an asphalt pavement. This is presumably due to compaction of the mix by traffic and appears to be independent of the overlay thickness, mix type, preoverlay preparation, and preoverlay rutting level.