HomeMy WebLinkAbout05V_E_Edina_Final Paper_ToEdinaSustainable Integrations
500 Pillsbury Drive S.E.
Minneapolis, MN 55455
April 30th, 2020
Ross Bintner
City of Edina
4801 W 50th St.
Edina, MN 55424
Dear Ross:
Thank you for choosing Sustainable Integrations to aid the City of Edina in reducing
carbon emissions related to city construction projects.
The report addresses the embedded carbon in the production of five common building
materials used in Edina: aggregate, concrete, asphalt, and five types of pipe (Polyvinyl Chloride
Pipe, High-Density Polyethylene Pipe, Cured-In-Place Pipe, Reinforced Concrete Pipe, and
Ductile Iron). An overall value for embedded carbon was obtained for each construction
material. The percent contribution to the total embedded carbon of each ingredient within the
building material was also evaluated.
Our analysis reveals that the majority of the embedded carbon in concrete and asphalt
are due to the production of the binder material. Out of the pipe materials, the 12’’diameter
ductile iron pipe had the highest embedded carbon. Sustainable alternatives for each material
are identified in this report. The results from each analysis were used to create an Embedded
Carbon Calculator, which the City of Edina can use to characterize the carbon emissions for
future projects involving the building materials.
We recognize the necessity of future research to fully characterize the lifecycle of each
material investigated in this report. To this end, the report presents pathways for future
characterization of embodied carbon in all four building materials, built upon the foundation of
our study. We enjoyed being on the front lines of new research on energy efficient building
materials and look forward to working with you and the City of Edina in our future careers.
Regards,
Celina Tragesser
Tasha Spencer
Jamie Klamerus
James Jorgenson
Enclosures:
1. Final Report
2. Embedded Carbon Calculator Excel Sheet
[Grab your reader’s attention with a great quote from the document or use this space to
emphasize a key point. To place this text box anywhere on the page, just drag it.]
2
EDINA SUSTAINABLE
INFRASTRUCTURE:
REDUCING NET-
EMBODIED CARBON
Prepared for the City of Edina
April 30, 2020
Tasha Spencer
Jamie Klamerus
James Jorgenson
Celina Tragesser
i
Certification Page
By signing below, the team members submit that this report was prepared by them and is their
original work to the best of their ability.
Celina Tragesser
Project Coordinator
Jamie Klamerus
Project Engineer
Tasha Spencer
Project Engineer
James Jorgenson
Project Engineer
ii
Executive Summary
The City of Edina has set a goal to reduce 80% of their current greenhouse gas (GHG)
emissions by the year 2050. As a step towards meeting this goal, Sustainable Integrations was
brought on to investigate decarbonization pathways within city construction projects and
recommend sustainable improvements. This study evaluated carbon emissions associated with
four commonly used construction materials in the city:
1. Aggregate
2. Concrete
3. Asphalt
4. Pipe (CIPP, RCP, Ductile Iron, HDPE, and PVC)
The analysis of these materials focused on assessing the so-called embedded carbon, that is, the
carbon emissions attributed to the extraction and fabrication processes of a material’s life cycle.
Literature was used to select each material’s carbon coefficient; these are quantities relating the
volume of carbon released for a unit volume of material used (lb CO2 / lb of material). The
volume of each material used in Edina construction projects was characterized from 2018
project material data. The 2018 project data provided material type and quantities for
construction materials purchased and installed in the city that year. Multiplying carbon
coefficients by volume, quantified yearly carbon emissions associated with the construction
materials.
An Embedded Carbon Calculator was created as a deliverable. This tool compiled all the
calculations and carbon coefficients into a spreadsheet. The spreadsheet can be used in future
projects to prioritize sustainable improvements based on updated carbon coefficients.
This study established that the binder material in asphalt and the Portland cement in concrete
are the largest carbon emission producers; for example, the carbon coefficient for asphalt
binder was approximately 160 times larger than that of aggregate. Regarding pipes, it was found
that ductile iron has the largest embedded carbon, in units of lb of CO2 per linear foot of pipe,
out of all the analyzed pipe types. In contrast, HDPE pipe material has the lowest embedded
carbon.
Sustainable Integrations recommends the City research tradeoffs associated with alternatives to
binder and cement then use the alternatives when they meet project needs. For example,
strength deficits in concrete are often associated with decreasing Portland cement content.
However, alternative additives to Portland cement, such as fly ash and blast furnace slag, can
reduce the embedded carbon of concrete significantly.
With regard to pipe materials, HDPE pipe is the most sustainable alternative to use where
applicable and endorsed by Sustainable Integrations. Appropriate HDPE installations include
above and below ground water, gas, sewage, and wastewater pipelines. Ductile iron has the
highest embedded carbon for pipes; therefore, limiting new installations is advised when other
options are present. As Ductile Iron pipe is commonly used for water transport, it can be
replaced with HDPE or PVC to achieve lower carbon emissions. Furthermore, it is suggested
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that the City request localized carbon coefficients and conduct a complete life cycle assessment
of these materials to establish more feasible improvements the City can invest in.
iv
Table of Contents
Abbreviations vii
1 Introduction ............................................................................................................................................... 1
2 Definition of Terms.................................................................................................................................. 2
3 Background Information ......................................................................................................................... 3
Sustainability ...................................................................................................................................... 3
Report Outline ................................................................................................................................. 3
4 Methodology .............................................................................................................................................. 4
Selecting the Top Four Materials ................................................................................................. 4
Top Four Building Materials........................................................................................................... 5
Concrete .................................................................................................................................... 5
Aggregate (Loose) ................................................................................................................... 6
Asphalt ....................................................................................................................................... 6
Pipe ............................................................................................................................................. 7
4.2.4.1 Cured-in Place Pipe (CIPP) .................................................................................................... 8
4.2.4.2 High-Density Polyethylene (HDPE) ..................................................................................... 8
4.2.4.3 Reinforced Concrete Pipe (RCP) ......................................................................................... 8
4.2.4.4 Ductile Iron Pipe ...................................................................................................................... 8
4.2.4.5 Polyvinyl Chloride Pipe (PVC) .............................................................................................. 8
5 Analysis & Sustainable Improvements .................................................................................................. 9
Concrete ............................................................................................................................................ 9
Aggregate ........................................................................................................................................ 10
Asphalt ............................................................................................................................................. 10
Pipes ................................................................................................................................................. 12
Carbon Benchmark ....................................................................................................................... 14
6 Future Studies ........................................................................................................................................ 15
Next Steps ...................................................................................................................................... 15
Future Research ............................................................................................................................ 15
Incorporating Manufacturer By-products in Projects ................................................... 15
Extend Lifespan ..................................................................................................................... 16
Effects of Transportation Distance ................................................................................... 16
Road Surface Effect on Gas Efficiency .............................................................................. 16
v
Deconstruction for Reuse .................................................................................................. 16
Effects of Disposal ................................................................................................................ 16
Absorption of CO2 ............................................................................................................... 17
7 Summary .................................................................................................................................................. 17
8 References............................................................................................................................................... 19
Appendix A MnDOT Curb and Gutter Drawings……………………………………………24
Appendix B Additional Information for Concrete & Aggregate………………………...……25
Appendix C Additional Information for Asphalt……………………………………………...28
Appendix D Additional Information for Pipe…………………………………………………29
Appendix E Schedule and Budget……………………………………………………….……34
vi
List of Figures
Figure 2-1 Terminology of carbon in the life cycle of construction materials 2
Figure 4-1 Top construction materials used in 2018, by cost 4
Figure 4-2 Percentage of each pipe type used by the City of Edina in 2018 7
Figure 5-1 Comparison of sustainable binder alternatives for concrete 10
Figure 5-2 Contribution of raw materials to volume and embedded carbon of
one unit of asphalt
11
Figure 5-3 Total CO2 produced by the City of Edina in 2018, by pipe type 12
Figure 5-4 The CO2 per linear foot of each pipe type with a 12” diameter 13
Figure A-1 MnDOT Curb and Gutter Designs 24
Figure E-1 Total planned hours compared to actual project hours spent 34
Figure E-2 Percent completion of each task
34
vii
List of Tables
Table 5-1 Carbon coefficients for components in concrete 9
Table 5-2 Carbon to dollar comparison 9
Table 5-3 Carbon to dollar comparison of asphalt 11
Table 5-4 Total CO2 emissions from 2018 construction projects involving
concrete, aggregate, asphalt, and various pipe materials.
14
Table B-1 SF concrete calculations 25
Table B-2 SY concrete calculations 25
Table B-3 Bulk Densities of Mix Materials 26
Table C-1 Breakdown of carbon emissions of asphalt components [E] 28
Table D-1 12 inch Diameter PVC CO2 Calculation Summary 29
Table D-2 12 inch Diameter HDPE CO2 Calculation Summary 30
Table D-3 12 inch Diameter CIPP CO2 Calculation Summary 30
Table D-4 12 inch Diameter RCP CO2 Calculation Summary 31
Table D-5 12 inch Diameter Ductile Iron CO2 Calculation Summary 31
Table D-6 PVC Primary Values and References 32
Table D-7 HDPE Primary Values and References 32
Table D-8 CIPP Primary Values and References 32
Table D-9 RCP Primary Values and References 33
Table D-10 Ductile Iron Primary Values and References 33
Table E-1 Project Budget with associated time and cost of each task. 35
Table F-1 Report outline showing section writer and reviewer. 36
viii
Abbreviations
C&D Construction and Demolition
CIPP Cured-In-Place Pipe
CO2 Carbon Dioxide
CY Cubic Yard
GHG Greenhouse Gas
HDPE High-Density Polyethylene Pipe
IPCC Intergovernmental Panel on Climate Change
ISI Institute for Sustainable Infrastructure
LF Linear Feet
LCA Life Cycle Assessment
MPCA Minnesota Pollution Control Agency
PVC Polyvinyl Chloride Pipe
RCP Reinforced Concrete Pipe
SF Square feet
SY Square Yard
VCP Vitrified Clay Pipe
1
1 Introduction
Public infrastructure serves as the skeleton of life for many communities. Without continued
maintenance and construction, the structures that connect people and places would be
underdeveloped and the quality of life would decline. As a result, accelerated by aging
infrastructure and growing populations, construction is an essential investment for
governments; a total of 302 billion dollars of U.S. funds were spent on new public construction
in 2018 alone [1]. To maximize the overall public benefit of these funds, there has been an
increasing interest, by both local and federal governments, in deploying sustainable building
practices. Sustainability is defined as the ability of a system to meet the needs of the present
without compromising the ability of future generations to meet their needs [2].
A key issue in achieving a sustainable future is the control and reduction of greenhouse gas
(GHG) emissions. These gases encompass carbon dioxide (CO2 ), methane, nitrous oxides, and
chlorofluorocarbons which are emitted at high rates in human activities such as burning fossil
fuels [3]. GHGs create a buffer in the atmosphere, trapping solar radiation on Earth. This effect
causes global warming, a major contributor to climate change [4]. Climate change adds
stressors to human life and the surrounding infrastructure.
One undesirable consequence of developing, building, and maintaining sustainable cities are the
GHG emissions associated with the construction process. The construction sector accounts for
nearly 40% of all GHGs produced by global industries [5]. Thus, in order to fully meet
sustainability objectives, government agencies need to find ways to build and maintain
infrastructure that produces less GHG emissions.
The City of Edina, Minnesota, has set a goal to reduce their current GHG emissions by 80% by
2050. An area where the city can implement change is within their construction projects,
specifically with material selection. This report investigates the City’s construction materials and
the most promising options for sustainable alternatives. Four common construction materials
(concrete, aggregate, asphalt, and pipes) remain the focus of this investigation, which aims to
characterize their carbon emissions associated with the extraction and fabrication processes as
well as indicate alternative materials to reduce carbon emissions. Literature has established
quantities relating volume of carbon released for a unit volume of material used, known as
carbon coefficients. After the major sources of carbon emissions are quantified, it is possible to
prioritize and recommend future sustainable improvements. As a result, Edina will be able to
compare carbon emissions with cost and identify sectors of construction in most need of
sustainable alternatives.
A spreadsheet calculator for the City of Edina was created as a project deliverable to be able to
calculate the embedded carbon for common projects performed by the city. This spreadsheet is
meant to be updated with more localized carbon coefficients once the values become available.
Substantial research is needed in the sustainable building field, beyond the scope of this report,
to more accurately quantify carbon emissions by making carbon coefficients more widely
available. This report provides a foundation of research on sustainable building materials for
Edina which will act as a pathway for future practices.
2
2 Definition of Terms
This analysis uses several key terms to describe and quantify GHG emissions. As several terms
are used interchangeably in this report, commonly used words are defined below. Figure 2-1
illustrates the commonly used terms.
• Life cycle of a product includes material extraction, fabrication, installation, maintenance,
and disposal [6].
• Life cycle assessment (LCA) traces the progression of each phase in the life cycle,
documenting the resources consumed and the emissions released [7].
• Carbon footprint is the amount of GHGs released into the atmosphere associated with
the production, use, and end-of-life of a product or service [8].
• Embodied carbon is the carbon footprint of a material. It is the total amount of GHG
emissions attributed to a material throughout its life cycle [9].
• Embedded carbon is the total amount of carbon emissions attributed to a material from
extraction to fabrication processes, and does not include all other life cycle emissions.
• Cradle-to-gate as it is the partial life cycle analysis, for quantifying embedded carbon, from
resource extraction (cradle) to the factory gate, prior to transportation to the
consumer [9].
Figure 2-1: Terminology of carbon in the life cycle of construction materials
Embodied and embedded carbon for a material are reported as a mass (pounds or kilograms) of
CO2 released because CO2 is the highest produced GHG and therefore responsible for the
greatest amount of environmental impact [6].
3
3 Background Information
The City of Edina covers an area of approximately 16 square miles within the Minneapolis
metro area. The land is 95 percent developed and largely residential [10]. As of 2018, Edina has
a population of approximately 52,000 people and the median income per household is $99,295
[10]. In general, the Edina community is interested in sustainability, and actions that will
promote this movement in the city.
Sustainability
Edina saw an opportunity to progress their sustainability mission as they move forward in
replacing highly used aging infrastructure in the city. The Edina Engineering Department
manages city contracts and has been implementing several reconstruction projects that would
ideally incorporate more sustainable solutions.
Edina wanted to understand how sustainability parameters are practiced within the Engineering
Department by conducting an Envision Sustainability Self-Assessment using the Institute for
Sustainable Infrastructure (ISI) rating scale. Envision with the ISI’s scoring system helps rate
project sustainability choices within 5 major categories: community quality of life, leadership,
resources, climate and risk, and the natural world [11]. Even more importantly than
benchmarking, the Envision assessment indicated areas where future improvements can be
made on projects. The Envision rating system serves as a best practice resource for guidance
on how to develop a project management system to foster sustainable designs.
The Envision Sustainability Self-Assessment analyzed the City’s neighborhood street
reconstruction program in 2015. The three Edina road reconstruction projects assessed were
Arden Park Drive and 54th Street ($8.5M), Birchcrest Boulevard ($3.5M), and Valley View Road
($2.0M). The total points earned for each project, respectively, were Arden-102, Birchcrest-
68, and Valley- 67 out of the 789 total points available [12].
Edina would like to improve their Envision rating because it is a marker for the success of
their sustainability mission. A section of Envision that the city can greatly improve their score in
is Resource Allocations, it embodies the choice and use of materials throughout their lifespan
[10]. The Envision review assessed a score of zero for resource sustainability in the three road
rehabilitations. The Sustainable Infrastructure Project mainly focuses on the Resource category
of Envision and how the city can select more sustainable materials to increase their ISI score.
Report Outline
The long-term goal is to characterize the lifetime carbon impact of every construction material,
including the fabrication, installation, maintenance, and removal phases. The scope of this report
is to perform a cradle-to-gate assessment of the four most commonly used construction
materials. The body of this report is separated into three sections: Methodology, Analysis &
Sustainable Improvements, and Future Work.
4
The Methodology section qualitatively describes the theory and process behind determining
the four most commonly used construction materials and their associated embedded carbon.
The Analysis & Sustainable Improvements section presents the values obtained for the
embedded carbon of concrete, aggregate, asphalt, and pipe, and delivers the results from the
analysis (calculations are provided in the Appendix). This section also identifies sustainable
improvements, or components of each material which contribute most heavily to the total
embedded carbon. Lastly, the Future Work section proposes the next steps for the city and
identifies areas of future research which show promise for continued GHG reduction.
4 Methodology
Selecting the Top Four Materials
Quantifying the embedded carbon in construction materials is an intensive process. To that
end, it was determined that only the top four materials used by the city would be selected for
this analysis. All the projects completed in 2018 were categorized by material and ranked by
total budget. Figure 4-1 presents a comparison between the budget allocated to different
physical construction materials.
Figure 4-1: Top construction materials used in 2018, by cost
Projects including specialty items, such as fire hydrants, valves, and construction signs, in
addition to construction administration, were not included in the above ranking. Note that the
landscaping category does not entail other materials on the list, and is limited to water, soil, and
trees. For the purpose of this analysis, the landscaping category was not considered a material
as it is not suspected to contribute significantly to carbon emissions.
5
Out of the remaining categories in Figure 4-1, the top four construction materials are pipe,
concrete, aggregate, and bituminous. Each of these construction materials have different
manufacturing processes and raw material components, and therefore required separate
analyses. The following sections describe the methodology for each construction material,
including several sub-categories within concrete, aggregate, asphalt, and pipe.
Top Four Building Materials
Concrete
In order to calculate the embedded carbon of concrete, the following assumptions were made:
• Any sort of support material, such as steel bars or wood frames were not included in
these calculations.
• CO2 was calculated in pounds (lb) CO2 per lb of material, and the CO2 of three main
materials in concrete were calculated: cement, fine aggregates, and coarse aggregates.
• Water and various admixtures were not considered in these calculations due to their
low contribution overall to the embedded carbon of concrete.
• Only coarse and fine aggregates incorporated in the concrete mix were considered.
• A standard M20 concrete mix ratio of 1 part cement to 1.5 parts fine aggregate to 3
parts coarse aggregate with a 1.54 safety factor was assumed.
Evaluating the embedded carbon of concrete first involved assessing how much concrete was
used by Edina in 2018. A copy of the 2018 Quantities spreadsheet was created, with each
individual project spreadsheet sorted according to item description. Once all concrete items
were isolated, any concrete items listed under “removal” were eliminated. The majority of the
construction projects completed with concrete were sidewalks, gutters, driveways, curbs, and
castings. Installed concrete was reported in a variety of units. Concrete items were sorted
according to the unit used to quantify the material: LF (linear foot), SF (square foot), SY (square
yard), and EA (each item as a whole unit).
For items with units of SF and SY, the volume of concrete was calculated by multiplying the
quantity of area by the depth, provided in the item description (Calculations in Appendix B [23,
24]).
Items with units of LF are MnDOT curbs and gutters: B618, D412, and Surmountable (See
Appendix A for drawings). To find the volume of concrete, the cross-sectional area of the
specified designs were multiplied by the LF.
Finding the volume of items that were labeled as EA was difficult, as the dimensions of these
items varied with each project and were not disclosed in the spreadsheet. Estimations were
made according to base designs provided by the City of Edina’s Standard Plates and
Specifications website.
Total compiled volume of concrete was then multiplied by the standard M20 concrete mix ratio
of 1:1.5:3 and a safety factor of 1.54 to establish the individual material’s volume within the
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concrete mix. Once the total cement, fine aggregate, and coarse aggregate volumes were
obtained, the volumes were then multiplied by the material’s respective bulk density in order to
obtain the weight of each material. These weights were then multiplied by the appropriate
carbon coefficient in order to obtain pounds of CO2 per pounds of material. These coefficients
are provided in the analysis portion of this report and detailed calculations are presented in
Appendix B [23, 24].
Aggregate (Loose)
In order to calculate the embedded carbon of loose aggregate, the following assumptions were
made:
• Use of recycled loose aggregates were not considered in these calculations.
• Aggregate incorporated in concrete or asphalt mix was not considered in these
calculations.
• Loose aggregates were assumed to be a mix of 50% coarse and 50% fines.
• Coarse and fine aggregates were assumed to have the same bulk density of 104 lb/ft3.
Loose aggregate used by Edina in 2018 was placed as a base in road construction, part of
retaining walls, and as a base for concrete sidewalks and roads. Determining the embedded
carbon of loose aggregates involved isolating loose aggregate items in the 2018 Quantities
spreadsheet and sorting according to the unit used to quantify the material: cubic yard (CY) and
ton.
For items with units of CY, the weight of loose aggregate was calculated by multiplying the
volume by the bulk density of aggregate. This weight was then converted to tons and added to
loose aggregate items already given in tons. Tons of loose aggregate were then multiplied by the
estimated percentage of coarse and fine aggregate present (50/50) in order to determine the
weight of coarse and fine aggregates. These weights were then multiplied by the respective
carbon coefficient. These coefficients are provided in the analysis portion of this report and
detailed calculations are presented in Appendix B [23, 24].
Asphalt
The following calculations are simplified in order to highlight the general relationship between
carbon and asphalt. These assumptions apply to the analysis:
• Support material, such as steel bars or wood frames were not included in these
calculations.
• The two ingredients in asphalt are binder (bituminous) and aggregate.
The City of Edina primarily uses asphalt for driveways and roads, and is open to using it as an
alternative to concrete for sidewalks, if asphalt proves more sustainable. Asphalt is
approximately 95% aggregate, and 5% bituminous binder [18]. A wide range of published values
for the weight of carbon produced per weight of material, carbon coefficients, were identified
in literature. As it was not possible to identify the most accurate source relevant to Edina,
several reputable sources were reported and compared for analysis. The data from 2018 was
7
converted to a volume of cubic yards or tons. The analysis for asphalt was significantly
simpler than concrete due to less ingredients and simpler given units. The specific asphalt
calculations are presented in Appendix C [16, 18].
Pipe
As shown in Figure 1, piping is one of the most used and most costly construction materials in
the City of Edina 2018 public projects. The types of pipe used in Edina are: cured-in-place pipe
(CIPP), reinforced concrete pipe (RCP), high-density polyethylene (HDPE), ductile iron, copper,
vitrified clay pipe (VCP), and polyvinyl chloride pipe (PVC). To determine which pipe type
would potentially have the largest impact on CO2 emissions, the percentage of LF of each pipe
installed was determined and is shown in Figure 4-2 below.
Figure 4-2: Percentage of each pipe type used by the City of Edina in 2018
Figure 4-2 shows CIPP, HDPE, RCP, ductile iron, and PVC pipes had the most LF
installed. Further analyses of the five most used pipe types were completed to characterize the
total CO2 emissions for each pipe type. Calculations were carried out for the actual pipe sizes
used by the City of Edina. This primarily consisted of determining the diameter and wall
thickness to calculate the cross section and volume. Then multiplying the volume by density to
determine the total weight, and the carbon coefficient (pounds of CO2 per pound of pipe) to
determine the total pounds of CO2 per linear foot of each pipe type. Using the results from
these calculations along with the quantities of materials used by the City of Edina, the total
pounds of CO2 produced in 2018 for each pipe type was determined.
Upon completion of these calculations, it was apparent that a 12 inch diameter was a common
size used in the construction industry for the top five pipe types. Edina only used 12 inch RCP
in their 2018 projects; therefore calculations were also completed for 12 inch CIPP, HDPE,
8
Ductile Iron, and PVC. Quantifying the CO2 per linear foot of each pipe type, considering a
12” diameter, allowed for a direct comparison between each pipe type.
The step-by-step calculations for each 12” diameter pipe are presented in Appendix D [6, 25-
43]. The following subsections give background information for each pipe type and further
clarification on calculations if applicable.
4.1.4.1 Cured-in Place Pipe (CIPP)
Cured-in-Place Pipe is most commonly used where an existing pipe is severely damaged and is
in need of replacement. CIPP piping is a jointless pipe lining that is inserted into an existing pipe
to extend the service life of the pipe.
To analyze the embedded carbon of CIPP piping, each component of CIPP piping should be
considered to achieve the most accurate results. CIPP piping consists of layers of flexible felt,
and fiberglass reinforcement to hold the resin inside the tube. In order to simplify the
calculations, a weighted average of each material density was used to produce a single value for
the density of CIPP pipe. The volumes of each material component were summed together to
get a single volume for the CIPP pipe.
4.1.4.2 High-Density Polyethylene (HDPE)
High-Density Polyethylene piping is commonly used for above and below ground municipal and
industrial pipelines. Higher density HDPE piping is currently being used for water, gas, sewage,
and wastewater distribution systems in Edina. The production of HDPE piping consists of
extrusion, cooling, hot embossing, and cutting. The raw materials used are HDPE pellets made
from virgin polyethylene granulates and recycled HDPE [6].
4.1.4.3 Reinforced Concrete Pipe (RCP)
Reinforced Concrete Pipe is commonly used for applications such as sanitary sewers, storm
drains, culverts, and irrigation distribution systems. RCP is composed of portland cement,
aggregate, water, and the steel reinforcement bars. The calculations for RCP were completed
using a weighted average of each component to produce a single value for density.
4.1.4.4 Ductile Iron Pipe
Ductile Iron Pipe is commonly used for potable water transmission. To avoid corrosion,
internal linings and external coatings are often applied. Ductile Iron pipe has a relatively long
lifespan when compared to other pipe types and can often exceed 100 years.
4.1.4.5 Polyvinyl Chloride Pipe (PVC)
Polyvinyl Chloride Pipe is most commonly used for plumbing and drainage applications. PVC has
become a common replacement for metal piping due to its flexibility, durability, strength, and
low cost.
9
5 Analysis & Sustainable Improvements
Each material has a quantified embedded carbon which can be used to analyze alternative
materials and technologies to reduce the GHG emissions. Each material: concrete,
aggregate, asphalt, and pipe can all be sustainably improved. This section identifies opportunities
within each material for simple sustainable improvements.
Concrete
The calculations for concrete are presented in Appendix B [23, 24]. The carbon coefficients for
the main components in concrete are shown in Table 5-1. Source [13] utilizes information on
concrete production from The Concrete Centre in the United Kingdom, source [14] utilizes
more regional concrete production information from the United States, and source [15] utilizes
information on concrete production from South Korea. The carbon coefficients vary depending
on numerous assumptions made by researchers and are generally region specific.
Table 5-1: Carbon coefficients for components in concrete
Concrete Component Carbon Coefficients (lb CO2/lb)
Cement
Fine Aggregate
(Sand)
Coarse
Aggregate
Blast Furnace
Slag
Fly
Ash
Source
Production
Source
0.9497 0.00323 0.00224 * 0.0722 [14] USA
0.9 0.0044** ** 0.057 0.0044 [13] UK
0.82 0.0139 0.82 0.143 0.027 [15] South Korea
*Not published
**Source does not distinguish between coarse and fine aggregate
Table 5-2: Carbon to dollar comparison
Carbon to Dollar Comparison
(using 2018 data)
Source
Production Source
$ / lb CO2 lb CO2 / $
0.74 1.36 [14] USA
0.77 1.30 [13] UK
0.20 5.00 [15] South Korea
In Table 5-2, the carbon to dollar comparison relates the embedded carbon to dollars spent in
2018. According to source [14], for every $0.74 spent on concrete, 1 pound of CO2 is
embedded. This parameter relates carbon emissions to budget, which can be used as a quick
estimate to calculate embedded carbon for large projects.
The embedded CO2 of cement mixtures using varying quantities of blast furnace slag and fly ash
were calculated. Fly ash is a coal combustion byproduct and blast furnace slag is a byproduct of
10
iron production. When mixed with lime and water, these alternatives form a compound
similar to Portland cement [19]. Figure 5-1 shows the estimated reduction of CO2 within a year
based upon Portland cement being substituted with either fly ash or blast furnace slag in
different ratios. These numbers show that even a small decrease in the amount of Portland
cement used will decrease the total amount of CO2.
Figure 5-1: Comparison of sustainable binder alternatives for concrete
The above figure represents the benefits to sustainability by using alternative binders but does
not address the negative consequences of alternative binders such as strength deficits. Further
research is necessary to wholly characterize the effects of alternative binders to the integrity of
concrete.
Aggregate
The calculations for loose aggregate are presented in Appendix B [23, 24]. While aggregates
have a relatively small carbon coefficient, they often are used in large quantities, which can
amplify the amount of embedded carbon in aggregates to comparable numbers. When focusing
explicitly on loose aggregate, or aggregates not used within concrete mix or asphalt, one
sustainable alternative is using recycled loose aggregate. Edina already utilizes this strategy and
in 2018, Edina used approximately 10,000 yd3 of reclaimed loose aggregate salvaged from city
construction sites. This equates to an estimated yearly reduction of 122,216 lbs of CO2.
Significant amounts of CO2 can be reduced if recycled loose aggregate is used in place of new
loose aggregate.
Asphalt
The calculations for asphalt are presented in Appendix C. Note that the results of this analysis
are only as accurate as the initial carbon coefficient values entered in (Table 5-3). The long term
goal is to obtain local carbon coefficients from manufacturers in order to select between
11
manufacturers. For the purpose of this analysis, several reputable sources were selected to
highlight the process. The results of the analysis are presented in Table 5-3.
Table 5-3: Carbon to dollar comparison of asphalt
Published Carbon Coefficient
Source
Carbon to Dollar Comparison
(using 2018 data)
lb CO2 / lb asphalt $ / lb CO2 lb CO2 / $
19.6 [16] $0.002 626.93
0.285 [17 $0.110 9.12
0.0238 [18] $1.314 0.76
Each of the above published carbon coefficients produce a significantly different value, resulting
in high uncertainty. While some of the above coefficients produce a total embedded carbon
value similar in magnitude to concrete, other sources differ by several factors of magnitude.
Furthermore, the above values should not be taken as fact, but rather as a starting point and
initial benchmark for future obtained carbon coefficients.
One accurate aspect of this analysis, which can be taken at face value, is the breakdown of the
contribution of each asphalt ingredient to the total embedded carbon. Figure 5-2 compares the
contribution of each raw material to the total volume and embedded carbon of asphalt. (See
Table C-1 in Appendix C [16, 18] for values used in the figure).
Figure 5-2: Contribution of raw materials to volume and embedded carbon of one unit of asphalt
The majority of the associated carbon emissions is from the binder material. Although the
binder only contributes to 5% of the total weight of asphalt, the CO2 coefficient of the binder
is approximately 160 times that of aggregate. There is an opportunity to increase the
sustainability of asphalt with alternative binders or by using processes which decrease the
0%20%40%60%80%100%
Contribtuion to
Embedded Carbon
Contribution to
Volume of Apshalt
Bituminous binder Aggregate
12
associated carbon emissions from binder production. However, any alternative binder
material must meet strength requirements set by the Minnesota Department of Transportation.
Pipes
To evaluate the total CO2 produced by various pipe types in the City of Edina in 2018, the CO2
per linear foot of each pipe type was calculated, taking into consideration the different pipe
diameters used. Examples of these calculations, considering a 12 inch diameter, are shown in
Appendix D.1 [6, 25-35]. These calculations gave the results shown in Figure 5-3 below.
Figure 5-3 : Total CO2 produced by the City of Edina in 2018, by pipe type
The total carbon produced is greatest for CIPP, followed by Ductile Iron, RCP, HDPE, and
PVC. Note that this is not an accurate representation of each pipe’s carbon intensity, or pounds
of CO2 per linear foot of pipe, as the quantity of material used is not considered. For example,
although CIPP produced the most emissions, it is not necessarily the most carbon intensive
since a significant amount more of CIPP was used. This does however give a good gauge on the
total CO2 produced from each pipe type by the City of Edina in 2018, showing which pipe types
are responsible for the majority of the CO2 produced.
A standardized pipe size allows for a direct comparison across the top 5 pipe types in terms of
the pounds of CO2 per linear foot of pipe manufactured. The results of this comparison,
considering a 12” diameter for each pipe type, are shown in Figure 5-4 below.
13
Figure 5-4: The CO2 per linear foot of each pipe type with a 12” diameter
From the results shown in Figure 5-4, final conclusions were made as far as which pipes are
more or less carbon intensive in terms of pounds of CO2 per linear foot. Ductile Iron pipes
should be avoided as much as possible because they have the highest CO2 per linear foot of
pipe. As Ductile Iron pipe is commonly used for water transport, it can be replaced with HDPE
or PVC to achieve lower carbon emissions. Although CIPP produces the second most CO2 per
linear foot and does not appear to be the best option, it is widely known as one of the most
sustainable material solutions. This is due to the fact that CIPP is used as a trenchless
rehabilitation method used to repair existing pipelines. The installation of CIPP normally
extends the life span of existing pipes by 50 years or more while avoiding the carbon intensive
aspects of a full pipe repair such as concrete or asphalt cutting, trenching, removal of the
existing pipe, installation of the new pipe, and concrete or asphalt repair. This is where the full
life cycle analysis will be crucial in the final decision as to which pipe types should be selected to
reduce future carbon emissions in construction projects.
Pipe values such as the dimensions, density, and carbon intensity vary from source to source,
creating uncertainty in the calculations. The sources and values found and used in this analysis
are shown in Appendix D.2 [6, 36-43]. Error can be attributed to the differences in the
manufacturing processes that are considered by each source as well as the specific material
composition used in the manufacturing process. To accommodate for these sources of error, a
carbon calculator for each pipe type was provided to the City of Edina. The calculator allows
the user to modify inputs, such as the carbon coefficient and density, in order to yield more
accurate results as more reliable inputs become available.
14
Carbon Benchmark
A summary of the total Carbon emitted in 2018 is provided in Table 5-4. This table can be used
as a benchmark for future years to compare the reduction in carbon emissions. As the City of
Edina implements more sustainable practices, they can expect to see a decrease in the yearly
CO2 emissions within each sector.
Table 5-4: Total CO2 emissions from 2018 construction projects involving concrete, aggregate, asphalt,
and various pipe materials.
Material Amount of material used in 2018 CO2 emissions produced in 2018
[lb CO2]
Concrete 10,280,731 lb 1,853,221
Aggregate (Loose) 117,136,620 lb 320,367
Asphalt 25,152,562 lb 7,168,480
CIPP 15,000 LF 486,732
RCP 2,926 LF 201,299
Ductile Iron 2,653 LF 158,355
HDPE 13,133 LF 52,989
PVC 1,701 LF 22,687
Total 9,614,298
Note that the above table should not be used to compare construction materials categories as
the underlying assumptions differ between sources (i.e. concrete and asphalt should not be
compared, but individual pipe materials can be compared).
15
6 Future Studies
Next Steps
This report paved the way for future research on sustainable construction materials in the City
of Edina. However, significant work is needed to fully and accurately characterize the materials
discussed in this report. The following actions are recommended next:
1. Ask manufacturers for localized data on carbon emissions. Localized values for
embedded carbon will produce reliable data that the City of Edina can use to begin
making significant reductions in CO2. This would allow for a more accurate
prioritization of material replacements and an accurate comparison between asphalt and
concrete for road surfaces.
2. Estimate the contribution to the total embedded carbon for each part of the material
life cycle (transportation, maintenance, and demolition). This may include suggestions in
section 6.2 below.
3. Compare options and trade-offs within each material. What are the most optimal
combinations of sustainable alternatives in terms of cost, maintenance, and demolition?
For example, while some binder alternatives may reduce the embedded carbon, they
will also likely reduce the strength and lifetime of the material.
4. Develop methods to incentivize the optimal sustainable solutions detected from the
previous step. For example, give preference to local manufacturers when bidding
projects or utilize a weighted ranking system for selecting materials, with a heavier
weight on carbon than monetary cost.
The following section elaborates on specific areas of research which may assist in performing
the above tasks.
Future Research
Many sustainable solutions were identified throughout the course of this investigation. Not
every idea could be investigated within the scope and schedule of this report. The following
topics showed promise for reducing carbon emissions. It is recommended that the City
conducts further research in these areas to meet their goal of 80% GHG reduction by 2050.
Incorporating Manufacturer By-products in Projects
Many manufacturing processes create by-products as a secondary result from synthesizing the
desired material. The formation of by-products wastes raw materials, but they are inevitably
produced during the energy intensive manufacturing process. The city is advised to investigate
byproducts that can replace traditional construction materials. Implementing these changes
would increase the ISI score for the Envision Leadership category, section LD2.1- Pursue By-
product Synergy Opportunities.
16
Extend Lifespan
Performing maintenance at optimal times on infrastructure such as bridges and roads has
proven to increase their lifespan. Research can be done to schedule maintenance that will
lengthen the longevity of structures. Scheduling maintenance at a frequency that will most
extend the lifespan could reduce the number of replacements and financially benefit the city
long term. Implementing these changes would increase the ISI score for the Envision Leadership
category, section LD3.1- Plan for Long Term Monitoring and Maintenance.
Effects of Transportation Distance
Transportation of materials to job sites adds to the material’s embodied carbon. Decreasing the
distance from manufacturer locations to job sites lowers emissions from vehicles. Quantifying
the portion of a material's embodied carbon attributed to transportation is advised to assess
the efficiency (cost, time, and carbon emissions) of using manufacturers located close to the
site. Implementing these changes would increase the ISI score for the Envision Resources
category, section RA1.4- Use Regional Materials.
Road Surface Effect on Gas Efficiency
Asphalt and concrete are the two most used materials for road surfaces. Different textures
promote gas efficiency by reducing friction between road and tires. Comparing CO2 emission
reductions for cars on various surfaces could impact future road design choices.
Deconstruction for Reuse
Deconstruction is the process of salvaging components for reuse and recycling after a structure
is disassembled [20]. Deconstruction is an alternative to demolition and disposal that
significantly reduces waste. Encouraging careful deconstruction maximizes the recovery of
materials, reduces the need for raw materials, and diverts demolition debris from landfills. The
process can be complicated and time consuming; additionally, certain materials are more ideal
for recovery than others. For the city’s sustainable mission, it is advised to design for
disassembly and assess what factors make materials more easily reused and recycled.
Implementing these changes would increase the ISI score for the Envision Resources category,
RA1.7- Provide for Deconstruction and Recycling.
Effects of Disposal
Construction materials are disposed of in various ways, and most materials that are not
recycled end up in landfills [21]. Different materials degrade at various rates and generate
various amounts of CO2. Further exploration can be conducted to characterize which materials
produce the most CO2 while degrading in landfills.
The Waste Reduction Hierarchy places “reducing materials” as the most important step for
reducing CO2 emissions from materials followed by reuse, recycle, recovery, and safe disposal
[22]. Thinking about this hierarchy is beneficial when prioritizing possible decarbonization
17
routes. Implementing these changes would increase the ISI score for the Envision Resources
category, section RA1.5- Divert Waste from Landfills.
Absorption of CO2
Certain materials like concrete and wood had been proven to absorb CO2 throughout their
lifespan which may offset the carbon footprint associated with manufacturing.
7 Summary
Sustainability is often thought of as a goal to be met in the future. Those goals will not be met
unless sustainable measures are implemented in the present. The City of Edina takes
sustainability seriously and aims high to see an 80% reduction of their current greenhouse gas
emissions by 2050. One sector that has proven to be difficult to sustainably improve for Edina
is construction, which scored low on the ISI rating system. Construction is a vital component of
keeping the city safe and efficient, especially as infrastructure ages and the population continues
to grow. Construction is notoriously unsustainable, with the lifecycle of the materials used
sporting high embodied carbon values. However, significant research has shown that there are
sustainable options in construction that are safe and can lower the embedded carbon. In
addition to using sustainable materials, other measures can be taken to reduce greenhouse gas
emissions attributed to the transportation, maintenance, and disposal lifecycle phases.
In this report, Sustainable Integrations presented Edina with a roadmap to quantify the amount
of carbon attributed with several high-use construction materials. The top four budget
construction materials in 2018 were concrete, aggregate, asphalt, and pipes. The five pipe types
included: Polyvinyl Chloride Pipe (PVC), High-Density Polyethylene Pipe (HDPE), Cured-In-
Place Pipe (CIPP), Reinforced Concrete Pipe, and Ductile Iron. We focused exclusively on
determining the embedded carbon through a cradle-to-gate assessment. By providing Edina with
carbon coefficients of these four materials and a method of calculating the specific embedded
carbon for each material, the city can make more informed choices where feasible.
Through our research, Sustainable Integrations established that the binder in concrete and
asphalt contained the highest embedded carbon. While asphalt binder only contributes to 5% of
the total weight of asphalt, the carbon coefficient of the binder is approximately 160 times that
of aggregate. Portland cement, the binder in concrete, only contributes a small portion of the
concrete mix but has a significantly high carbon coefficient. Alternatives to Portland cement,
such as fly ash and blast furnace slag, can decrease the embedded carbon of concrete
significantly. We recommend future research regarding the effect of alternative binders in
concrete and asphalt in their life cycles. Regarding pipe materials, HDPE pipe is the most
sustainable alternative in terms of embedded carbon. It is recommended to use HDPE
installations where applicable, in above and below ground water, gas, sewage, and wastewater
pipelines. Ductile iron has the highest embedded carbon for pipe; therefore, it is advised to limit
new installations. Ductile Iron pipe is commonly used for water transport and can be replaced
with HDPE or PVC to achieve lower carbon emissions.
18
During the process of finding the four construction materials, researching their carbon
coefficients, and calculating their embedded carbon, Sustainable Integrations compiled all the
calculations and coefficients into a spreadsheet. This spreadsheet can be used by city engineers
and other employees to gain insight on how much embedded carbon future projects could
contain. The embedded carbon calculator spreadsheet was created as a tool to aid Edina in
meeting its sustainability goals in the years to come. While more research is needed to fully
characterize sustainable solutions, Edina now has the advantage of knowing the embedded
carbon of their construction materials. This information can help Edina formulate policy
surrounding sustainable construction practices and eventually be polished to be incorporated
within specifications and bidding contracts.
19
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21
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24
Appendix A- MnDOT Curb and Gutter Drawings
When calculating the volume of concrete used by Edina in 2018, the data provided quantified
concrete in various units. One unit used was linear feet (LF). Items with units of LF are MnDOT
curbs and gutters: B618, D412, and Surmountable (Figure A1). To find the volume of concrete,
the cross-sectional area of the specified designs were multiplied by the LF.
Figure A-1: MnDOT Curb and Gutter Designs
25
Appendix B - Additional Information for Concrete & Aggregate
B.1 Calculations
Calculating the embedded carbon of concrete and loose aggregate involved two main parts. The
first part involved converting units used within the 2018 Quantities spreadsheet to a single
volume unit. The second part involved finding the weights of each individual material and then
multiplying that weight by the appropriate carbon coefficient.
The following tables (Tables B-1& B-2) show how data was presented in the 2018 Quantities
spreadsheet, and the calculations needed to find the volume of concrete.
Table B-1: SF concrete calculations
Rows from
actual
spreadsheet
SF Item Description Quantities Used Volume (ft3)
BA-445
4-INCH CONCRETE
WALK 2 0.67
Description of
Column
Unit Used
(ft2)
Depth of concrete is 4
inches
2 quantities of
unit, so 2 Square
feet
Multiply “Quantities Used” by
Depth provided “Item Description”
Calculations
(2 𝑎𝑟2)(4 �ℎ𝑙𝑎�𝑎𝑟)(1 𝑎𝑟
12 �ℎ𝑙𝑎�𝑎𝑟)
=0.67 𝑎𝑟3
Table B-2: SY concrete calculations
Rows from
actual
spreadsheet
SY Item Description Quantities Used Volume (ft3)
BA-445
6" CONCRETE
DRIVEWAY
PAVEMENT 49 220.5
Description
of Column
Unit
Used
(yd2)
Depth of
concrete is 6
inches
49 quantities of
unit, so 49
Square yards
Multiply “Quantities Used” by Depth
provided “Item Description”
Calculations
(49 𝑦𝑎2)(9 𝑎𝑟2
1 𝑦𝑎2)(6 �ℎ𝑙𝑎�𝑎𝑟)(1 𝑎𝑟
12 �ℎ𝑙𝑎�𝑎𝑟)
=220.5 𝑎𝑟3
26
Loose aggregate quantities were provided in the same style in the spreadsheet as concrete.
Loose aggregates were given in units of cubic yards and tons. For cubic yards, loose aggregate
was multiplied by a combined bulk aggregate density of 104 lb/ft3, and then converted to tons by
dividing the weight by 2000 lbs.
The second part of the calculations involved finding the individual weights of the different raw
materials that make up concrete and loose aggregate.
Concrete is composed of portland cement, fine aggregate, coarse aggregate, water, and various
admixtures. Water and various admixtures were not considered in these calculations due to
their low contribution overall to the embedded carbon of concrete. A standard M20 concrete
mix ratio of 1 part cement to 1.5 parts fine aggregate to 3 parts coarse aggregate was assumed.
This ratio is then used to determine the volume of the mix material within the overall volume
of concrete. This ratio was then multiplied by a safety factor of 1.54. This safety factor accounts
for the approximately 50% increase in volume from wet to dry concrete. Once a volume is
obtained, the volume is multiplied by the mix material’s bulk density (Table B-3) to obtain the
weight of each mix material. The weight is multiplied by the respective carbon coefficient
(unique to each mix material) to obtain lbs of CO2. Carbon coefficients are provided in the
analysis portion of the report.
Example, calculate the lbs of CO2 contributed by portland cement in 100 ft3 of concrete:
1:1.5:3 concrete mix ratio, total concrete mix ratio of 5.5
1 part cement, so 1
5.5 ∗1.54 ∗100 𝑎𝑟3 𝑎𝑙𝑙𝑎𝑟𝑎𝑟𝑎=28 𝑎𝑟3 𝑙𝑙𝑟𝑟𝑙𝑎𝑙𝑎 𝑎𝑎𝑙𝑎𝑙𝑟
28 𝑎𝑟3𝑙𝑙𝑟𝑟𝑙𝑎𝑙𝑎 𝑎𝑎𝑙𝑎𝑙𝑟∗93.64 𝑙𝑎
𝑎𝑟3 =2,622 𝑙𝑎𝑟 𝑙𝑙𝑟𝑟𝑙𝑎𝑙𝑎 𝑎𝑎𝑙𝑎𝑙𝑟
2,622 𝑙𝑎 𝑙𝑙𝑟𝑟𝑙𝑎𝑙𝑎 𝑎𝑎𝑙𝑎𝑙𝑟∗0.9497 𝑙𝑎 𝐶𝑂2
𝑙𝑎 𝑙𝑙𝑟𝑟𝑙𝑎𝑙𝑎 𝑎𝑎𝑙𝑎𝑙𝑟=2,490 𝑙𝑎 𝐶𝑂2
In order to find the weight of each mix material within concrete, the bulk density of each mix
material must be used. Bulk densities of the mix materials are provided in Table B-3:
Table B-3: Bulk Densities of Mix Materials
Units are lb material/ft3 Source: [23], [24]
Cement Fine Aggregate (Sand) Coarse Aggregate Blast Furnace Slag Fly Ash
93.64 105 103 76 70
For determining the lbs of CO2 from loose aggregates, once the quantity of loose aggregate is
calculated in tons, the percentage of coarse and fine aggregates that make up the total loose
aggregate must be considered. Even though the same bulk density can be used for coarse and
fine aggregate, the carbon coefficients are unique to each type of aggregate. For calculating the
27
total CO2 emitted by construction materials used by Edina in 2018, an 50/50 ratio was
assumed. Meaning, loose aggregate was assumed to be composed of 50% fine aggregate (sand)
by weight and 50% coarse aggregate by weight. Multiplying the total loose aggregate by the
respective percentage gives the weight of the respective aggregate type. The weight is
multiplied by the respective carbon coefficient to obtain lbs of CO2. Carbon coefficients are
provided in the analysis portion of the report.
Example, calculate the lbs of CO2 contributed by fine aggregate in 10 tons of loose
aggregate:
10 𝑟𝑙𝑙𝑟 𝑙𝑙𝑙𝑟𝑎 𝑎𝑎𝑎𝑟𝑎𝑎𝑎𝑟𝑎∗0.5 𝑙𝑎𝑟𝑎𝑎𝑙𝑟𝑎𝑎𝑎 𝑎�ℎ𝑙𝑎𝑟=5 𝑟𝑙𝑙𝑟 𝑎�ℎ𝑙𝑎 𝑎𝑎𝑎𝑟𝑎𝑎𝑎𝑟𝑎𝑟
5 𝑟𝑙𝑙𝑟∗2000 𝑙𝑎𝑟
1 𝑟𝑙𝑙=10,000 𝑙𝑎𝑟 𝑎�ℎ𝑙𝑎 𝑎𝑎𝑎𝑟𝑎𝑎𝑎𝑟𝑎
10,000 𝑙𝑎 𝑎�ℎ𝑙𝑎 𝑎𝑎𝑎𝑟𝑎𝑎𝑎𝑟𝑎𝑟∗0.00323 𝑙𝑎 𝐶𝑂2
𝑙𝑎 𝑙𝑙𝑟𝑟𝑙𝑎𝑙𝑎 𝑎𝑎𝑙𝑎𝑙𝑟=32.3 𝑙𝑎 𝐶𝑂2
The same carbon coefficients used for coarse and fine aggregates in concrete were used for
loose aggregate. This is because the coarse and fine aggregates used in concrete are defined as
loose aggregates until they are incorporated into the concrete mix. It is assumed there is
negligible change, especially when only considering the fabrication portion of the material life
cycle.
28
Appendix C - Additional Information for Asphalt
C.1 Calculations
This section describes the basic calculations used to produce the asphalt tab of the Embedded
Carbon Calculator Spreadsheet. The following assumptions apply to the calculation:
• Any sort of support material, such as steel bars or wood frames were not included in
these calculations.
• CO2 was calculated in pounds (lb) of CO2 per ton of material, and the CO2 of the two
materials in asphalt, binder (bituminous) and aggregate.
• The density of asphalt is assumed to be 145 lb/ft3,
• The carbon coefficient from source [16] is used, 19.6 lb CO2 per lb asphalt.
For this sample calculation, a 6-inch-deep, 3-foot-wide, 6-yard-long piece of sidewalk will be
laid. This equates to 1 cubic yard.
This process can be repeated by simply replacing the constant, 19.6 lb CO2/lb asphalt with a
different value. Three values are provided in the spreadsheet tool. The final quantity of CO2
produced varies greatly depending on the source used for the initial carbon coefficient. This can
be attributed to varied initial assumptions, errors in analysis, and the use of different material
components.
Table C-1 displays the breakdown of carbon emissions for each component in asphalt [18].
Although the specific values in the table are from one source, which may or may not be used in
the future, the ratio between values is consistent and can be used regardless of the initial
carbon coefficient selected.
Table C-1: Breakdown of carbon emissions of asphalt components [18]
Component %
Weight
lb CO2 / lb
material
lb CO2 from
component
Total lb CO2 / lb
asphalt
Aggregate 0.95 0.0026 0.0025
0.0238 Asphalt cement
(binder)
0.05 0.426 0.0213
29
Appendix D - Additional Information for Pipe
D.1 Calculations
As mentioned in the pipe methodology, Quantifying the CO2 per linear foot of each pipe type,
considering a 12” diameter, allowed for a direct comparison between each pipe type. Step-by-
step CO2 calculation summary tables are shown below.
D.1.1 PVC
The following table summarizes the calculations completed to determine and standardize the
CO2 emissions produced per linear foot of 12” diameter PVC pipe.
Table D-1: 12 inch Diameter PVC CO2 Calculation Summary
Line
Number Value Description Values Calculation By
Line Number
(If Applicable)
References
1 Nominal Pipe Size [in] 12
2 Outter Diameter [in] 12.75 [25]
3 Inside Diameter [in] 11.889 [25]
4 Thickness [in] 0.861 2 - 3
5 Cross Sectional Area [in2] 16.662
6 Volume Per Linear Foot [in3] 199.939
7 Density [lb/in3] 0.0524 [6]
8 Total Weight Per Foot [lb] 10.477 6 x 7
9 CO2 [kg CO2/kg PVC] 1.7 [26]
10 Total CO2 [lb CO2/Linear ft PVC] 17.811 8 x 9
30
D.1.2 HDPE
The following table summarizes the calculations completed to determine and standardize the
CO2 emissions produced per linear foot of 12” diameter HDPE pipe.
Table D-2: 12 inch Diameter HDPE CO2 Calculation Summary
Line
Number Value Description Values
Calculation By
Line Number
(If Applicable)
References
1 Nominal Pipe Size 12
2 Outer Diameter [in] 12.75 [27]
3 Thickness [in] 1.159 [27]
4 Cross Sectional Area [in2] 22.157
5 Cross Sectional Area [ft2] 0.154
6 Density [lb/in3] 0.034 [28]
7 Volume Per Linear foot [in3] 265.884
8 Total Weight [lb] 9.029 6 x 7
9 CO2 [kg CO2/kg HDPE] 1.478 [29]
10 Total CO2 [lb CO2/Linear ft HDPE] 13.345 8 x 10
D.1.3 CIPP
The following table summarizes the calculations completed to determine and standardize the
CO2 emissions produced per linear foot of 12” diameter CIPP pipe.
Table D-3: 12 inch Diameter CIPP CO2 Calculation Summary
Line
Number Value Description Values Calculation By Line Number
(If Applicable) References
1 Outer Diameter [in] 12
2 Thickness 0.3543 [30]
3 Cross Sectional Area [in2] 6.580
4 Volume [in3] Per Linear Foot 78.958
5 Total Weight [lb] Per Linear Foot 3.454 4 x 6
6 Total Density 0.0437 [6]
7 CO2 [lb CO2/lb CIPP] 16.917 [6]
8 Total CO2 [lb CO2/Linear ft CIPP] 58.434 5 x 7
31
D.1.4 RCP
The following table summarizes the calculations completed to determine and standardize the
CO2 emissions produced per linear foot of 12” diameter RCP pipe.
Table D-4: 12 inch Diameter RCP CO2 Calculation Summary
Line
Number Value Description Values Calculation By
Line Number
(If Applicable) References
1 Outer Diameter [in] 12
2 Wall Thickness [in] 2 [31]
3 Density [kg/ft^3] 175.75 [32]
4 Cross-sectional Area [in2] 34.557
5 Cross-sectional Area [ft2] 0.240
6 Volume per linear ft [ft3] 0.240
7 Total Weight Per Linear ft [kg] 42.177 6 x 3 [32]
8 CO2 [kg CO2/kg RCP] 0.153 [33]
9 Total CO2 [kg CO2/linear ft RCP] 6.453 7 x 8
10 Total CO2 [lb CO2/linear ft RCP] 14.227
D.1.5 Ductile Iron
The following table summarizes the calculations completed to determine and standardize the
CO2 emissions produced per linear foot of 12” diameter Ductile Iron pipe.
Table D-5: 12 inch Diameter Ductile Iron CO2 Calculation Summary
Line
Number Value Description Values
Calculation By
Line Number
(If Applicable) References
1 Outter Diameter [in] 12
2 Wall Thickness [in] 0.4 [34]
3 Cross-Sectional Area [in2] 7.414
4 Cross-Sectional Area [ft2] 0.051
5 Volume [ft3] Per Linear Foot 0.051
6 Density [lb/ft3] 455.72 [35]
7 Weight [lb] Per Linear Foot 23.464 5 x 6
8 Embedded Carbon [lb CO2/lb] 2.7 [33]
9 Total CO2 [lb CO2/linear ft
Ductile Iron Pipe] 63.352 7 x 8
32
D.2 Pipe Values and Sources
As mentioned in the pipe analysis, section 5.4, uncertainty is present for pipe calculations largely
due to pipe values such as density and carbon intensity or pounds of CO2 per pound of pipe
varying from source to source. To accommodate for this error, carbon calculators were
provided to the City of Edina that currently are using the values highlighted green in the tables
below to calculate the desired coefficient of pounds of CO2 per linear foot of pipe. As these
values become more standardized and other sources are found, new values can be added to
these tables for comparison and substituted into the carbon calculators to achieve a more
accurate result.
D.2.1 PVC
Table D-6: PVC Primary Values and References
PVC Density [lb/in3] Reference CO2 Factor
[lb CO2/lb PVC] Reference
Source 1 0.0524 [6] 4.86 [28]
Source 2 0.05 [36] 1.7 [26]
Source 3 4.4 [37]
D.2.2 HDPE
Table D-7: HDPE Primary Values and References
HDPE Density [lb/in3] Reference CO2 Factor
[lb CO2/lb HDPE] Reference
Source 1 0.03486 [6] 1.478 [29]
Source 2 0.03396 [28] 1.99 [38]
Source 3 2.97 [39]
Source 4 2.52 [33]
Source 5 2 [37]
D.2.3 CIPP
Table D-8: CIPP Primary Values and References
CIPP Density [lb/in3] Reference CO2 Factor
[lb CO2/lb CIPP] Reference
Source 1 0.0437 [6] 16.917 [6]
33
D.2.4 RCP
Table D-9: RCP Primary Values and References
RCP Density [kg/ft3] Reference CO2 Factor
[lb CO2/lb RCP] Reference
Source 1 175.75 [32] 0.48 [6]
Source 2 145.8 [40] 0.113 [41]
Source 3 0.148 [28]
Source 4 0.147 [39]
Source 5 0.153 [33]
Source 6 0.12 [42]
D.2.5 Ductile Iron
Table D-10: Ductile Iron Primary Values and References
Ductile Iron Density [lb/ft3] Reference CO2 Factor
[lb CO2/lb Ductile Iron] Reference
Source 1 455.72 [35] 2.7 [33]
Source 2 437 [43] 1.43 [28]
Source 3 2.55 [38]
34
Appendix E - Schedule and Budget
At the beginning of this project a schedule and budget was created that estimated the hours
each task would require to be completed. Figures E-1 shows the difference between cumulative
planned hours and actual project hours spent over the course of the project on a weekly basis.
Figure E-2
Figure E-1: Total planned hours compared to actual project hours spent
Figure E-2: Percent completion of each task
Table E-1 gives more detail on the budget with total hours planned, actual time, and cost
associated with each project task.
35
Table E-1: Project Budget with associated time and cost of each task.
Project Task Projected time
expenditure
(hrs)
Projected
cost
Responsible
team
member(s)
Actual time
expenditure
(hrs)
Actual
cost
Project Plan (PP) 15.0 $1,125.00 ALL 23.0 $1,725.00
Meet with
Mentor(s) 36.0 $2,700.00 ALL 44.3 $3,318.75
Biweekly Project
Reports 25.0 $1,875.00 ALL 34.3 $2,568.75
Report 1st Draft 36.0 $2,700.00 ALL 53 $3,975.00
Report 2nd Draft 38.0 $2,850.00 ALL 26.0 $1,950.00
Final Report 38.0 $2,850.00 ALL 81.5 $6,112.50
Midterm
Presentation 32.0 $2,400.00 ALL 34.5 $2,587.50
Final Presentation 49.0 $3,675.00 ALL 46.0 $3,450.00
Task #1: ISI
Category Review 36.0 $2,700.00 ALL 12.0 $900.00
Task #2: Carbon
Analysis 61.0 $4,575.00
Tasha, Jim,
Celina 71.5 $5,362.50
Task #3: Reserach
Alternatives 90.0 $6,750.00
Tasha, Jim,
Celina 3.5 $262.50
Task #4: Consult
Experts 40.0 $3,000.00 Jamie 3.5 $262.50
Task #5:
Specification
Writing 50.0 $3,750.00 None 0.0 $0.00
Task #6: Life Cycle
Analysis 68.0 $5,100.00 ALL 0.0 $0.00
Task #7: Cost
Analysis 70.0 $5,250.00
Celina and
Tasha 22.0 $1,650.00
Task #8:
Determine
Standardized
Reporting Methods 51.0 $3,825.00 ALL 6.0 $450.00
TOTAL 735.0 $55,125.00 461.0 $34,575.00
(Avg. Per Person) 183.75 $9,187.50 115.25 $5,762.50