Sustainable Road Construction

Rajib B. Mallick

Nov 22, 2016

Sustainable Road

Construction

Why?

What? How?

Why?

The NATURAL greenhouse effect

The NATURAL greenhouse effect

The NATURAL greenhouse effect

The NATURAL greenhouse effect

The Industrial Revolution

We’ve been producing a lot of this!

The ARTIFICIAL greenhouse effect

+43% more

Global temperature is rising

And

Continuous exponential growth…

"Anyone who believes exponential growth can go on forever in a finite world is either a madman or an economist."

Kenneth Boulding

Road Structure

2006 Post Keynesian Summer School - UMKC

Roads lead to economic development

.

More demand, inadequate budget, poor engineering -> poor roads

Depletion of aggregates

15,000 tonnes of aggregate per km

Source: USGS

Increase in haul distance with depletion of natural aggregate

• Mining of aggregates from river beds lead to the formation of “incisions” in river beds

• Leads to dropping of the water level

• Leads to a loss of precious ground water

Impact on River and Water Resources

What?

Sustainable Development •Development that •Meets the needs of the present •Without compromising the ability of

future generations to meet their own needs

Reduced Cost Reduced Noise

Reduced Emission

Sustainable Road Construction

• System characteristics that encompasses a road’s ability to

• Achieve the engineering goals for which it was constructed

• Preserve and (ideally) restore surrounding ecosystems

• Use financial, human, and environmental resources economically

• Meet basic human needs such as health, safety, equity, employment, comfort, and happiness

Important

• It is unlikely a truly “sustainable” road will be constructed in the near future • Pursuit of sustainability should be viewed

as a process of continual improvement towards an ultimate goal

• Need processes, actions, and features • That advance the state of the practice

towards more sustainable road construction

Examples

• Recycling

• Low energy materials

• Alternative cementitious materials

• Porous pavements

• Low CO2 producing road materials

• Cool pavements

• Materials and processes that extend life of roads

Example - Recycling

RAP - Reclaimed Asphalt Pavement

How?

Systems Approach

• Balanced consideration of trade-offs and competing priorities for a given project

• In some cases, it may not be productive and it may even be counterproductive to introduce certain features that are thought to be sustainable

• Trade-off that must be continually assessed to move towards more sustainable solutions

• Roads must be viewed as part of the overall transportation system and the civil infrastructure system

Use Life Cycle Assessment (LCA)

• A structured method that quantifies environmental impact over the full life cycle of a system or product, including impacts that occur throughout the supply chain

Why LCA?

• For improving the production and performance of products or systems

• For selection of specific products as part of planning and prioritization

• For developing appropriate indicators of environmental performance

• For identifying trade-offs in decision making regarding specific products or systems

• For identifying impacts that might occur over the entire life of the product, and the system that includes the product as a result of changes made to a product

Example

• LCA can be applied to determine the total environmental impact of a ton of aggregate throughout its life, starting from its production, going through processing, transportation through the different stages and use and to the end of life

• The end of life can include recycling, remanufacturing, reuse without reprocessing or recycling into other products

Framework

Four Phases

• Goal and Scope definition

• Inventory analysis

• Impact assessment

• Interpretation

LCA - Essential Features

•Defined system with its boundary (geographic and temporal)

•A functional unit

•Required quality of data

Impact Assessment Phase

• The environmental outflows are converted into environmental impacts in terms of impacts on

• Humans

• Nature

• Depletion of resources

• Through the use of established assessment methodologies

Interpretation

• The results of LCA are summarized and discussed, major factors are identified, and sensitivity analyses results are utilized for making conclusions and decisions

• An LCA for comparing alternatives should be transparent to readers, must have review through an independent panel

Example of Comparison

• New Construction 2 inch HMA over 6 inch Base

• Alternative 1: Maintained two times in 15 years by applying a new 2 inch layer

• Alternative 2: Maintained two times in 15 years by applying a 2 inch layer, containing 50% RAP

Example of data used in LCA

• The energy input for bitumen production is 3.98 MJ/kg (3.77E+03 BTU/kg) and 226 g/kg for CO2 emissions

• ISO 14044 defines feedstock energy as heat that is contained in raw material but not commonly used as an energy source

• Bitumen’s feedstock energy is estimated to be 40.2 MJ/kg

• The total energy of bitumen production is 44.21 MJ/kg (4.19E+04 BTU/kg) if feedstock is taken into consideration

Alternative 1

Alternative 2

Needs • Fundamental quantitative data on the relative

environmental sustainability of common treatments

• Research policies

• Technology

• Materials

• Specifications

• Equipment

• Capacity building

• Life-cycle analysis

How can we work together?

•Develop •Processes •Actions •Features •That lead to sustainable road construction

•Sustainability Rating System •Education

Thank you!