LIFE CYCLE BENEFITS OF RECYCLED MATERIAL IN HIGHWAY CONSTRUCTION

Transcription

1 LIFE CYCLE BENEFITS OF RECYCLED MATERIAL IN HIGHWAY CONSTRUCTION Kelly Del Ponte, M.S. Geological Engineering Program, University of Wisconsin-Madison Engineering Hall, 11 Engineering Drive, Madison, WI 0 Tel: (0) 0-; kdelponte@wisc.edu Bharat Madras Natarajan Geological Engineering Program, University of Wisconsin-Madison Engineering Hall, 11 Engineering Drive, Madison, WI 0 Tel: (1) -0; madrasntara@wisc.edu Angela Pakes Ahlman, P.E., LEED AP, Corresponding Author Geological Engineering Program and Recycled Materials Resource Center, University of Wisconsin-Madison 0 Engineering Hall, 11 Engineering Dr., Madison, WI 0 Tel: (0) 0-; angela.pakes@wisc.edu Andrew Baker Geological Engineering Program, University of Wisconsin-Madison Engineering Hall, 11 Engineering Drive, Madison, WI 0 abaker@wisc.edu Erik Elliott Geological Engineering Program, University of Wisconsin-Madison Engineering Hall, 11 Engineering Drive, Madison, WI 0 efelliott@wisc.edu Tuncer B. Edil, Ph.D., P.E., D.GE, Dist. M. ASCE Geological Engineering Program and Recycled Materials Resource Center, University of Wisconsin-Madison Engineering Hall, 11 Engineering Dr., Madison, WI 0 Tel: (0) -; tbedil@wisc.edu Total words: 1 words text + Figures/Tables 0 words (each) = 1 Submission Date: August 1, 01

2 ABSTRACT The use of recycled materials in highway construction has the potential to achieve significant benefits affecting the triple-bottom line (environment, prosperity, and society). Although state departments of transportation (DOTs) have been at the forefront of introducing recycled materials, they have been unable to clearly convey the benefits in quantitative and transparent manners using easily understood metrics. Information on sustainability assessment characteristics, i.e. energy and water consumption, is lacking. To determine the benefits of using recycled materials for six member state DOTs in a pool fund, the Recycled Materials Resource Center (RMRC) was tasked to undertake a project with the objective of quantifying the environmental and economic life cycle benefits associated with the incorporation of recycled materials and industrial byproducts in highway construction. An analysis of the environmental benefits (i.e. CO emissions, energy consumption and water consumption) associated by substituting recycled materials for conventional virgin materials in highway construction was conducted using PaLATE (Pavement Life-cycle Assessment Tool for Environmental and Economic Effects), a life cycle assessment (LCA) tool developed with RMRC sponsorship. An economic impact analysis was conducted comparing unit prices of virgin with recycled materials. The analysis shows significant environmental and economic savings in all member states. Total environmental savings from recycled materials use approximately equates to the energy consumption of 1,000 U.S. households per year,,00 bathtubs of water and the CO emissions produced by,000 cars per year. Total system-wide economic savings from recycled materials use are estimated to be $0 million. Keywords: Environmental impact, Life cycle assessment, Recycled material, Sustainability

3 INTRODUCTION Over,000 kilometers (1,000 miles) of highways in the National Highway System form the backbone of our -million-kilometer (-million-mile) public road network. These highways are continuously being constructed and rehabilitated, requiring large amounts of natural raw materials, producing waste and consuming energy and emitting greenhouse gases (1, ). In order to reduce the economic and environmental costs, state Departments of Transportations (DOTs) have been using recycled materials in highway construction. The Recycled Materials Resource Center (RMRC, located at the University of Wisconsin-Madison, and many governmental agencies have developed fact sheets on various recycled materials and industrial byproducts for their use in highway construction applications. These fact sheets typically have addressed the engineering properties and environmental suitability issues relevant to various applications and in some cases have incorporated design guidelines and construction specifications. However, direct information on sustainability assessment characteristics, i.e., Greenhouse Gas (GHG) emissions, energy and water consumption and life cycle cost benefits is not yet readily available. State agencies may track yearly use of quantities for major recycled materials such as fly ash in concrete, recycled asphalt pavement (RAP), recycled concrete aggregate (RCA), etc., but they have not yet calculated the life cycle and cost benefits accrued by substituting these materials for conventional materials. Project by project tracking of recycled materials using post-bid award information has been a challenge. With a lack of information or an easy way to track recycled material use, DOTs have not been able to clearly convey the benefits in a quantitative and easily understood manner. The RMRC submitted a previous report based upon the preliminary analysis and findings of the study. This report was submitted to the Geo-Chicago 01 conference (). This paper expands upon these preliminary findings. Objectives The objective of this study is to quantify the environmental and economic life cycle benefits associated with the incorporation of recycled materials and industrial byproducts to highway pavement construction. In order to realistically quantify these benefits, data on the recycled materials quantities used by each RMRC pool fund member state DOT was collected and analyzed, using a Life Cycle Assessment (LCA) tool, for 01. The RMRC member state DOTs that have provided 01 data for this study are: Georgia (GDOT), Illinois (IDOT), Minnesota (MnDOT), Pennsylvania (PennDOT), Virginia (VDOT) and Wisconsin (WisDOT). DATA COLLECTION Recycled Materials Used in 01 To determine recycled materials use, RMRC member state DOTs (GA, IL, MN, PA, VA and WI) were asked to report quantities of recycled materials for the calendar or fiscal year of 01. Although recycled material use quantities were not being tracked by most of the DOTs, information on as-let items for projects within the time period for each state was available. In order to calculate the quantities of recycled materials from as-let material quantities, a set of assumptions regarding average design specifications was needed for each state DOT (e.g., the percentage replacement of cement with fly ash, percent recycled asphalt pavement (RAP) in hot mix asphalt (HMA), pavement dimensional specifications, etc.). This was determined through interviews and correspondence with engineers from each member state. These assumptions and averages were

4 then used to calculate the amounts of recycled materials used in HMA, fly ash in concrete mixes and recycled aggregates in base course layers. Average Material Cost After collecting data on the quantity of recycled materials used in 01 by RMRC member states, a second phase of data collection began to determine the average unit price of both recycled materials and virgin (conventional, non-recycled) materials. In general, an average unit price (dollars per ton of material) of each recycled material was found by surveying providers, pavement associations and various material associations in each state. The unit cost of each material does not include transportation costs to the mix plant or to the site. The unit cost of equivalent volumes of virgin materials was estimated using a weighted average of Engineering News-Record (ENR) () historic material price indices. ENR tracks the price of raw paving materials of twenty cities on a monthly basis including: Atlanta, Baltimore, Chicago, Minneapolis, Philadelphia and Pittsburgh. The monthly prices starting in July of 01 through January of 01 were averaged in order to determine the average price of aggregate, base course materials and cement in each city. The individual city price averages were then averaged with the average price of all the cities in order to normalize any prices skewed high or low. Because most state DOTs track the price of liquid asphalt more frequently than ENR, these indices were used instead of ENR estimates. ENR does not track material price in a Wisconsin city, therefore local pavement associations and material providers were asked to estimate savings in a unit cost by using recycled materials. ANALYSIS PaLATE Life Cycled Assessment PaLATE LCA Overview Life cycle assessments (LCA) can assist in gaining a better understanding of the environmental impacts of materials and processes throughout the product life cycle (cradle-to-grave) and provide relevant data in order to make informed decisions (). The International Organization for Standardization (ISO) 100 series provides general principles and a framework for an LCA study, detailing four phases of an LCA: (a) definition of goals and scope, (b) inventory analysis, (c) impact assessment and (d) interpretation. In general, LCAs should have defined system boundaries, functioning units and inputs/outputs. For most pavement LCAs, the defined system boundaries are materials, transportation of materials, construction, use, maintenance and end-oflife (). The goal of using LCA for this study is to calculate the environmental benefits of using recycled materials and industrial by-products in highway pavement. To achieve this goal, the LCA tool PaLATE (Pavement Life-cycle Assessment Tool for Environmental and Economic Effects), was chosen. PaLATE, developed for the RMRC (), follows the production of materials, transportation of materials, construction, maintenance and end-of-life processes. Initial material inputs are analyzed based on the equipment used to produce and transport them to the construction site. Emissions due to construction, transportation, maintenance and production are calculated from the equipment used in all processes. Many of the outputs of PaLATE are based upon the volumes or weight of materials used and the parameters of equipment used, such as the

5 productivity and fuel consumption of each machine. PaLATE furthers its impact assessment by outputting not only greenhouse gases (GHG) emissions, but also energy use, water consumption, particulate matter, waste generation and human toxicity potentials. The first version of PaLATE was developed in 00, and while the range of environmental outputs of PaLATE is wide, these are limited by potential out-of-date databases. As such, the PaLATE databases were partly updated in order to run this analysis reflecting the industry conditions in 01. The details of this update will not be discussed further herein, however, details can be found in (). Assumptions and Parameters Determining specific design parameters (such as pavement thicknesses and fly ash replacement of concrete) for every DOT project over the annual period was impractical, so certain standard practice assumptions were made (Gary Whited, program manager of the Construction Materials Support Center at the University of Wisconsin Madison, personal communication). The general assumptions made when running the LCA analysis in PaLATE included: 1. A 1:1 replacement volume of virgin materials with recycled materials was assumed, despite the known varying mechanical properties.. All materials were assumed to be utilized in initial construction operations.. Both cement and fly ash were assumed to be delivered by cement trucks over a one-way distance of 0 kilometers (00 miles) from the processing site to the concrete mix plant.. All RAP and RCA was assumed to be processed and reused on site with a transportation distance of zero.. All other materials included in HMA, ready-mix concrete and the base course were assumed to be delivered by trucks over a one-way distance of 0 kilometers ( miles) from the processing site to the asphalt or concrete mix plant.. All equipment was assumed to be the default equipment type for each process in PaLATE.. All densities of materials were assumed to be the listed densities in PaLATE. It should be noted the assumptions listed above are general assumptions of the recycled materials reported by each state. More specific assumptions can be found in the final RMRC project report, Life Cycle Benefits of Recycled Material in State DOT Road Construction. Approach to PaLATE Analysis The quantities of recycled materials used by each member state were analyzed in PaLATE to determine environmental impacts and benefits of the recycled materials use. These environmental impacts and resulting benefits were analyzed comparatively by using the same equivalent volume of virgin materials. Three environmental impact factors: CO emissions, energy consumption and water consumption were deemed sufficient for evaluation of the state materials. PaLATE determines the environmental impacts based on three categories: material production, material transportation and construction processes (equipment). Material production includes the processes associated with extracting or generating the materials, such as RAP milling and virgin aggregate quarrying. Material transportation incorporates the impacts associated with transporting each material the specified distance in the chosen vehicle. Processes (equipment) consist of the impacts associated with installing the materials, such as paving, placing and compaction. The first step in conducting the PaLATE analysis was to compile the collected recycled materials data for all of the member states and to convert the quantities from weight to volume

6 using the given densities in PaLATE. Then, equivalent virgin material volumes were calculated for their recycled counterpart. Both the recycled and virgin material quantities were input into a PaLATE sheet, from which the specific environmental impact for each material in terms of production, transportation and processes were determined. Finally, the environmental impact of recycled versus virgin material was analyzed. Economic Impacts Analysis Parameters and Assumptions Due to the nature of the collected data, a true Life Cycle Cost Analysis (LCCA) could not be performed without making some significant and perhaps unreasonable assumptions. Given just material quantities and broad assumptions as to how each material was applied to a highway, an LCCA could not be performed to a reasonable degree of accuracy. Instead the cost savings realized by each state in 01 were estimated by comparing the prices of recycled and virgin materials. The general cost assumptions made in the analysis are listed below. Included in these assumptions are also the assumptions used to calculate the total quantities of recycled materials utilized in The cost of hauling, either to the mixing plant or to the construction site, was not included in the unit price of each material.. Materials were assumed to be purchased individually and not as part of mixture, i.e. a distinction between the paving contractor and state agency was not made. Approach to Economic Impact Analysis As previously mentioned, in order to estimate the economic savings achieved, a comparison of prices of recycled materials and virgin materials per ton of material was needed. Due to the many factors involved in calculating the price of material, this study determined the average purchase price per ton of both recycled materials and virgin materials without the cost of transportation. As with the environmental analysis, the recycled and virgin materials were first equated to equivalent volumes and then converted to corresponding weights. These weights were then used to calculate the cost of recycled materials and virgin materials used. Total savings and unit savings per ton of recycled material could then be estimated for each state. The estimated 01 recycled material unit costs are shown in the table below (Table 1).

7 TABLE 1 Estimated 01 Recycled Material Unit Costs ($/ton) Material Georgia Illinois Minnesota Pennsylvania Virginia Wisconsin RAP in HMA $1.00 $0.0 $. $0.00 $1. $. RAS $.00 $ $.0 $.00 Fly Ash $. $0.00 $0.00 $.0 $.0 $0.00 RCA $.0 $.0 $ $.0 RAP in Base $ Note that values are from correspondence with materials engineers and contractors in each state; () These savings are meant to be a conservative estimate of the potential economic savings of using recycled materials. The true economic impact of using recycled materials cannot be determined unless all aspects of how both a recycled material and its equivalent virgin material is priced and applied in construction are known. RESULTS AND TRENDS ACROSS STATES Quantities of Recycled Materials Used RAP in HMA and fly ash were utilized by all six member state DOTs, while recycled asphalt shingles (RAS) and RCA were utilized by at least four of the member state DOTs. The figure below shows the tonnage of each major recycled material used per state in the LCA and economic analyses (Figure 1). Although crumb rubber and ground granulated furnace slag were used by a number of states, they were not presented.

8 Tons of Recycled Material 1,00,000 1,00,000 1,00,000 1,000,000 00,000 00,000 00,000 00,000 0 GDOT IDOT MnDOT PennDOT VDOT WisDOT RAP in HMA RAS Fly Ash RCA RAP in Base FIGURE 1 Total Recycled Material Utilized in 01 (tons) RAP in HMA was utilized the most by weight and volume across all states. Additionally, RAP in HMA use varied significantly with geography. In the southern states (GA and VA) HMA pavement is more widely used compared to the northern states (IL, MN and WI). Northern states tend to use Portland Cement Concrete (PCC) pavement for their major highways. This is reflected in the recycled material use for each state. The northern states, where PCC is more common, use higher amounts of RCA, and the southern states, where HMA is widely utilized, use higher amounts of RAP, particularly in HMA. IDOT used above average quantities of all four widely used recycled materials (RAP in HMA, RAS, fly ash, and RCA), while WisDOT used more RAS, fly ash and RCA. GDOT and VDOT used above average amounts of RAP in HMA, and MnDOT used proportionately higher amounts of fly ash. As shown in the figure below, WisDOT used the most recycled materials with approximately 1. million tons, followed closely by IDOT and GDOT with approximately 1. million tons each (Figure ). VDOT uses slightly more than half of the quantity of recycled

9 Total Recycled Material Used (tons) Total Highway Budget ($ billions) 1 material that WisDOT uses, while MnDOT and PennDOT use about one third of the quantity of WisDOT.,000,000 $.00 1,00,000 1,00,000 1,00,000 1,00,000 $.0 $.00 $.0 1,000,000 $.00 00,000 00,000 00,000 00,000 $1.0 $1.00 $0.0 0 GDOT IDOT MnDOT PennDOT VDOT WisDOT $ Total Reycled Material Used Total Budget FIGURE Recycled Material and Total Highway Budget for FY 01 IDOT total tonnage includes those materials not used in the LCA or economic analysis. The figure above shows that member state DOTs with a higher highway budget usually have a lower use of recycled materials, while those member state DOTs with a lower budget had a higher use of recycled materials (Figure ). PennDOT and VDOT have the highest budgets but use less recycled materials than GDOT, IDOT, and WisDOT. An exception to this is MnDOT, which has a comparable budget to GDOT, IDOT, and WisDOT, but only used tonnage of recycled materials comparable to PennDOT. Environmental Results Environmental impacts of roadway construction are quantified through CO emissions, energy consumption and water consumption. The environmental savings from using recycled materials is calculated as the difference between the impact categories for the recycled materials and their virgin equivalents at a 1:1 replacement ratio. These environmental savings are shown in the figure below (Figure ).

10 CO Savings (Mg) Energy Savings (TJ) Water Savings (kg) 1 1,00 1,00 1, Energy Consumption (a) 0,000 00,000 0,000 00,000 0,000 00,000,000 0,000 0,000 0 Water Consumption (b) 0,000 0,000 0,000 0,000 0,000 0,000 0,000,000 0 CO Emissions (c) FIGURE Environmental Savings Comparison There are significant savings for all states in every environmental factor. CO savings span from 0, Mg to 0,1 Mg, energy savings range from TJ to 1,11 TJ, while savings in water consumption range from 1, kg to 0, kg. Additionally, the trends for all of the environmental savings are very similar. GDOT can expect the highest environmental savings across the board with IDOT expecting the second highest savings. VDOT and WisDOT are similar for all environmental factors. MnDOT and PennDOT can expect lower environmental savings in all categories. From the figure above it was determined that all environmental categories display similar trends (Figure ). Thus, CO emissions savings was used to represent all environmental categories (energy consumption, water consumption, and CO emissions) and the trends discussed between CO emissions savings and recycled materials use hold true for the other environmental categories. The figure below plots the tons of each recycled material used and the CO emissions saved in every state (Figure ). The figure below demonstrates that states which use more recycled materials should expect more CO emissions savings (Figure ). MnDOT and PennDOT use the least amount of recycled material, thus are shown to save the least CO emissions. However, not all states follow this trend. WisDOT, which uses the most recycled material, does not see higher

11 Tons of Recycled Material CO Emissions Savings (Mg) CO emissions savings than GDOT and IDOT. This is because some materials have a larger CO emissions saving capacity than others. A trend between CO emissions savings and RAP in HMA is observed; states that use large amounts of RAP in HMA see high environmental savings. RAP in HMA is the most widely used recycled material, accounting for about % of the total recycled materials used by the six states studies. Hence, the CO emissions savings reflected for each state is largely influenced by the amount of RAP in HMA the state uses. However, total use of recycled materials has a significant effect as well. This balance can be seen by comparing WisDOT with MnDOT and PennDOT. These three states use a comparable amount of RAP in HMA, but WisDOT has significantly higher CO emissions savings due to a much higher use of total recycled materials. Another example of the balance between RAP in HMA use and total recycled materials is found when comparing WisDOT and VDOT. Both states see comparable CO emissions savings despite differences in amount and type of recycled material used. VDOT used about 1 million tons of recycled material mainly consisting of RAP in HMA, while WisDOT uses about 1. million tons of a larger variety of recycled materials. WisDOT might expect higher total savings compared to VDOT, but the results do not support this rationale , , , , , , , ,000 0 GDOT IDOT MnDOT PennDOT VDOT WisDOT RAP in HMA RAS Fly Ash RCA RAP in Base CO Emissions Savings (Mg) FIGURE Tonnage of Recycled Materials and CO Emissions Savings

12 The large effect of RAP in HMA on CO emissions savings is further illustrated in the figure below, which shows each recycled material use as a percent of total recycled materials for each state and CO emissions savings per ton of total recycled materials for each state (Figure ). The figure below, unlike the figure above, does not consider the total amount of recycled materials used (Figure, Figure ). It allows for a clearer view into which recycled materials have the highest potential for environmental savings. GDOT and VDOT have the highest percent of RAP in HMA (both over 0%) and see the highest CO emissions savings per ton. The correlation can also be seen with WisDOT, which has the lowest percent RAP in HMA of the recycled materials used and the lowest CO emissions savings per ton. This trend shows that RAP in HMA has a significant influence on CO emissions savings of the materials studied. This is likely because RAP in HMA is a binder replacement. Producing the binder for a pavement is extremely energy and emissions intensive process, thus using RAP in HMA reduces the need for the asphalt binder and the associated environmental impacts. RAS and fly ash, both binder replacements, also would likely generate the same influence on environmental savings. However, they are not recycled to the extent that RAP in HMA is and their effects are therefore overshadowed.

13 Percent of Total Recycled Materials CO Emissions Savings per Ton (Mg/ton) % % 0.00% % 0.00% % 0.00% % %.00% 0.00% GDOT IDOT MnDOT PennDOT VDOT WisDOT % RAP in HMA % RAS % Fly Ash % RCA 0 1 % RAP in Base CO Emissions Savings per Ton (Mg/ton) FIGURE Percent of Material and CO Emissions Savings per Ton The figure below shows the percent reductions in environmental factors for each state due to 1:1 replacement of virgin materials with recycled materials (Figure ). High percent savings are expected for all environmental factors, with water consumption savings having the highest (% - %) and energy savings having the lowest (% - %). Despite energy consumption showing the lowest percent savings of the three environmental factors, reducing the energy needed for road construction by at least % due to the use of recycled materials is significant. It can therefore be concluded that utilizing recycled materials in road construction, in all the states studied, greatly reduces the environmental strain associated with road construction.

14 1 0.0%.0% 0.0%.0% 0.0%.0% GDOT IDOT MnDOT PennDOT VDOT WisDOT Energy Consumption Water Consumption CO₂ Emissions FIGURE Percent Reductions of Environmental Impact Note that the Y-axis begins at %. Additionally, note that percent reductions are calculated from a 1:1 replacement of virgin materials with recycled materials. Economic Results The estimated cost savings of each state ranged from $ to $1. billion as shown in the figure below (Figure ). As expected, the economic benefit of using RAP in HMA as a binder and aggregate replacement was the highest of all the recycled materials as it was used in large quantities in most states. RAS and fly ash also had high estimated cost savings. These three recycled materials all replace a percentage of virgin materials that act as binders. Binder for asphalt mixes were priced in 01, on average, at about $00/ton and cement were, on average, at about $1/ton, making these the most expensive materials in their respective pavements (of the materials under consideration for this study). Recycled materials that replaced aggregates generally priced at a much lower cost between $ and $0 per ton, thus did not have as large an impact on total cost savings. Comparing GDOT and IDOT, both states use similar quantities of recycled material, however IDOT saved about $ million more than GDOT. This discrepancy can be attributed to the fact that IDOT recycles more binder replacements, specifically RAS and fly ash, compared to GDOT.

15 Total Tons of Recycled Material Total Saved (in $ million) 1,000,000 $0.00 1,00,000 $1.00 1,00,000 $1.00 1,00,000 $1.00 1,00,000 $1.00 1,000,000 $.00 00,000 $.00 00,000 $.00 00,000 $.00 00,000 $.00 0 GDOT IDOT MnDOT PennDOT VDOT WisDOT $ RAP in HMA RAS Fly Ash RCA RAP in Base Total Saved (million $) FIGURE Cost Savings from Recycled Material Use Variability in cost savings per material may account for some of the differences in total savings, but does not account for the disproportionately higher savings seen by VDOT, shown in the figure above (Figure ). VDOT utilized only the fourth largest amount of recycled materials however, exceeded the savings of each other state by an average of about $. million. The disproportionality between VDOTs savings and tons of recycled materials utilized cannot be explained by the higher cost savings realized through the use of binder replacements. A possible explanation for this discrepancy is the differences in local cost structure. Cost savings per ton, seen in the bars in the figure below, is the difference between the price of a ton of virgin material and the price of a ton of recycled material (Figure ). The

16 combination of different materials individual cost savings per ton in a given state makes up that states local cost structure. As expected, binder replacement materials, RAS, RAP and fly ash, show the greatest savings per ton in each state. Additionally, note the correlation between savings per ton and total savings, shown in the line graph on the figure below (Figure ). This trend is attributed to the fact that, certain materials, ones replacing expensive virgin materials, have a greater impact on total cost savings. That is to say, using more recycled material will, on average, leads to increased savings, but savings will vary depending on quantity and type of recycled materials utilized. Take VDOT as an example, having average total recycled material tonnage compared to other states, VDOT would be expected to see average cost savings. However, VDOT sees the greatest total savings across all states, which can be attributed to VDOT s utilization of materials which have higher savings per ton in Virginia. The savings per ton realized utilizing RAP in HMA, although slightly higher in Virginia than in most states, is especially significant as RAP in HMA makes up % of VDOT s total tonnage of recycled material. It can be concluded that savings are not simply derived from the quantity of materials recycled, but are a combination of both quantity and type of recycled materials utilized.

17 Cost Savings per Ton Total Saved (in $ million) 1 $10 $0.00 $1.00 $0 $1.00 $0 $1.00 $1.00 $0 $.00 $.00 $0 $.00 $0 $.00 $.00 $0 GDOT IDOT MnDOT PennDOT VDOT WisDOT $ RAP in HMA RAS Fly Ash RCA RAP in Base Total Saved (in $million) FIGURE Savings per ton of Recycled Material ($) Comparing average savings, total tons of recycled material used and total cost savings, as seen in the figure below, the previously stated conclusion is reiterated (Figure ). Take GDOT, IDOT and WisDOT as an example, all display lower average savings per ton of recycled material but higher total recycled material usage. As a result, those states display intermediate total cost savings compared to the other states. On the other hand, VDOT displays the highest average savings per ton of recycled material and intermediate total tons of recycled material used compared to the other states; therefore, its total cost savings are the highest. This trend reiterates the conclusion that the economic impact realized through the use of recycled material is dependent on both the type and quantity of recycled materials as well as the local price structure.

18 Total Cost Savings ($ millions) & Avg Savings per Ton ($/ton) Total Recycled Material Use (tons) 1 $0.0 $1 1. $1 1. $1 1. $1 1. $ 1.0 $ 0. $ 0. $ 0. $ 0. $0 GDOT IDOT MnDOT PennDOT VDOT WisDOT RAP in HMA RAS Fly Ash RCA RAP in Base Avg Savings per Ton ($/ton) Total Recycled Material Use (tons) FIGURE Total Savings, Average Savings, and Total Recycled Materials Use CONCLUSIONS Using the data collected from the six-member state DOTs of the RMRC pool fund, the environmental and economic benefits associated with the use of recycled materials were quantified. The updated LCA tool PaLATE was used for the analysis of environmental benefits. The economic benefits were calculated by comparing the average price of virgin materials and recycled materials based on the cost structure in each state. The total environmental savings from recycled materials use across all member states are estimated to be,00 TJ of energy, 1. million kg of water and,000 Mg of CO. This approximately equates to the energy consumption of 1,000 U.S. households per year,,00 bathtubs of water, and the CO emissions produced by,000 cars per year (,, 1). The use of RAP in HMA resulted in the greatest environmental savings compared to the other materials under question as it was the most widely used. However, the overall environmental benefits

19 resulting from the use of recycled materials in roads are a combination of both the amount and type of materials utilized. The total economic savings from recycled materials use across all member states are estimated to be $ million. Materials used as partial replacement for traditional binders, RAP, RAS and fly ash, had the higher cost savings compared to materials used in substitution of aggregates, RAP and RCA. Similar to environmental savings, total cost savings are dependent on usage rate of each material, as well as local cost structure in which the material is being sourced. ACKNOWLEDGMENT The pool fund supporting the Recycled Materials Resource Center provided funding for this project. Various engineers from each member state DOT provided the required material data and reviewed the various assumptions: Steve Krebbs, Winnie Okello, Gerard Geib, Edward Wallingford, Mike Fitch, Mathew Mueller, Sheila Beshears, Richard Douds, and Peter Wu. Their contribution is acknowledged. Various material suppliers and state pavement associations provided cost data. Gary Whited from the UW-Madison and formerly from WisDOT aided in the data collection and interpretation for this research. Within the Recycled Materials Resource Center, Eleanor Bloom and Aaron Canton assisted with data collection and analysis. Greg Horstmeier, a student intern from the UW-Madison assisted in data collection. Julia Wilcots, a student intern from Princeton University also assisted with preliminary data collection.

20 REFERENCES 1. AASHTO. Primer on Transportation and Climate Change. Publication PCRT-1, American Association of State Highway and Transportation Officials, 00.. Gambatese, J., & Rahendran, S. Sustainable Roadway Construction: Energy Consumption and Material Waste Generation of Roadways. Paper presented at the Construction Research Congress, 00.. Bloom, E., Del Ponte, K., Madras Natarajan, B., Pakes Ahlman, A., Edil, T., & Whited, G. State DOT Life Cycle Benefits of Recycled Material in Road Construction. Final Report 01 (in press). Engineering New Record. Historical Cost Indicies from Engineering newsrecord (pp. 10 volumes). New York: McGraw-Hill, 11.. ISO. Environmental management - Life cycle assessment - Principles and framework. Publication 100:00. International Organization for Standardization Santero, N., Loijos, A., Akbarian, M., & Ochsendorf, J. Methods, Impacts, and Opportunities in the Concrete Pavement Life Cycle. Cambridge, MA Horvath, A. PaLATE: Pavement Life-cycle Assessment Tool for Environmental and Economic Effects: University of California, Berkely Pakes Ahlman, A., Edil, T., & Del Ponte, K. Life Cycle Benefits of Recycled Material in State DOT Road Construction. Final Report 01 (in press). Lipper, D. L., ozer, H., Al-Qadi, I. L., El-Khatib, A. K., Yang, R., Dahhan, A. Z.,... Trepanier, J. S. Illinois Highway Materials Sustainability Efforts of 01. Publication FHWA-ICT Urbana, IL U.S. Energy Information Anministration. How much electricity does an American home use?. U.S. Energy Information Administration, October 1, PWB. Shower and Bath Fact Sheet. Portland Water Bureau EPA. Average Annual Emission and Fuel Consumption for Gasoline-Fueled Passenger Cars and Light Trucks. Publication EPA0-F-0-0. Environmental Protection Agency