Eco-efficient Pavement Construction Materials

F. Pacheco-Torgal, Serji Amirkhanian, Hao Wang, Erik Schlangen, Fernando Pacheco-Torgal

• Publisher: Woodhead Publishing
• Year: 2020
• Print ISBN: 9780128189818
• eBook ISBN: 9780128189825
• Topic: Technology & Engineering
• Subtopic: Civil Engineering
• Index: Technology & Engineering

Eco-efficient Pavement Construction Materials acquaints engineers with research findings on new eco-efficient pavement materials and how they can be incorporated into future pavements. Divided into three distinctive parts, the book emphasizes current research topics such as pavements with recycled waste, pavements for climate change mitigation, self-healing pavements, and pavements with energy harvesting potential. Part One considers techniques for recycling, Part Two reviews the contribution of pavements for climate change mitigation, including cool pavements, the development of new coatings for high albedo targets, and the design of pervious pavements. Finally, Part Three focuses on self-healing pavements, addressing novel materials and design and performance.Finally, the book discusses the case of pavements with energy harvesting potential, addressing different technologies on this field.- Offers a clear and concise lifecycle assessment of asphalt pavement recycling for greenhouse gas emission with temporal aspects- Applies key research trends to green the pavement industry- Includes techniques for recycling waste materials, the design of cool pavements, self-healing mechanisms, and key steps in energy harvesting

1

Introduction to eco-efficient pavement materials

F. Pacheco-Torgal¹ and Serji Amirkhanian², ¹C-TAC Research Centre, University of Minho, Guimarães, Portugal, ²University of Alabama, Tuscaloosa, AL, United States

Abstract

The state of the Planet is briefly reviewed through different models used in the last four decades. A Scopus survey concerning the scientific production on the field of civil engineering and the subfield of pavements is carried out. The survey proves not only that the aforementioned subfield is not receiving enough research efforts but also that the environmental issues need much more attention from the scientific community. Brief comments on the crucial importance of climate change effects for pavement materials are included. A book outline is also included.

Keywords

Sustainable development; resource efficiency; Scopus; civil engineering; pavements; roads; sustainability; climate change resilience

1.1 The state of the Planet

Almost 50 years ago several scientists used a system dynamics computer model to simulate the interactions of population, food production, industrial production, pollution, and consumption of nonrenewable natural resources, having predicted that during the 21st century the Earth’s capacity would be exhausted, resulting in the collapse of human civilization [1]. Two decades later, in an update of this study, the same authors showed that some limits had already been crossed [2]. Meadows et al. [3] conducted a 30-year update of the original study and concluded that period was nothing than a waste of time and that Humanity has done very little to avoid the collapse of the Planet’s environment. Turner [4] also studied Meadows’ projections with 30 years of real events and concluded that the global system is on an unsustainable trajectory unless there is a substantial and rapid reduction in consumptive behavior. One year later Rockström et al. [5] suggested an innovative approach for global sustainability defining nine interdependent planetary boundaries. They also stated that humanity has already transgressed three planetary boundaries for changes to the global nitrogen cycle, rate of biodiversity loss, and above all climate change. More details on the suggested planetary boundaries framework can be found in Ref. [6]. The UN Intergovernmental Panel on Climate Change released a special report warning that “Limiting global warming to 1.5°C would require rapid, far-reaching, and unprecedented changes in all aspects of society” [7]. The target of 1.5°C is being the threshold beyond which climate change would imperil species survival. Randers et al. [8] stated that the world will not reach all Sustainable Development Goals by 2030, nor by 2050, and that the global safety margin will continue to decline. And in truth, Distelkamp and Meyer [9] mentioned that although the global average CO₂ intensity is projected to decline against 2015, it is expected that global CO₂ emissions will further increase by 44% up to 53 Gt in 2050. In order to keep economy running, several institutions such as UNEP, World Bank or the European Commission thus claim for green economy and green growth that is expected to do more with less while improving human wellbeing and social equity but some believe that that is not compatible with the ecologic limits of the Planet [10]. Some authors [11] stated that using a low-tech approach can not only contribute to an increase in resilience but can also create the cultural conditions needed for politics and macroeconomics of degrowth to emerge. On the other hand, Holford [12] reminded us not only that technology has control over humans but also that it is driven by the neoliberal socioeconomic quest for profit maximization and economic growth. And others even claim that only a severe shut down of the main carbon polluters could have meaningful results still they seem to forget that such action would have a major impact on the increase of poverty. One of the solutions recommended by several authors including the 2018 Nobel Laureate of Economy is the carbon tax. Nordhaus [13] suggested carbon tax as an important way for households, firms, and governments to reduce emissions cost-effectively. He also claimed that carbon prices will strengthen incentives for research and development of technologies that will lower the cost of reducing emissions. Others, however, claim that the wellbeing of the rich must decline rapidly as the only solution to ensure that the environmental burden associated with the rise of the wellbeing of the poor does not override the sustainable carrying capacity of planet Earth [14]. Be there as it may and while no wonder solutions are found, which can green industries without shutting it down, incremental improvements are the only short-term solution for the problem. This was the rationale that led to the concept of eco-efficiency first coined in the book “Changing course” [15] in the context of the 1992 Earth Summit process. This concept includes “the development of products … while progressively reducing their environmental impact and consumption of raw materials throughout their life cycle, to a level compatible with the capacity of the planet.”

1.2 Scientific production on civil engineering and pavements

Civil engineering is the scientific area that investigates and forms professions to deal with the challenges posed by the built environment that is still associated with the world’s highest consumption of raw materials, as well as very high energy consumption. Of course the fact that recent surveys show that students interested in civil engineering do not believe in anthropogenic climate change [16,17] is a problem that also requires urgent attention because it is impossible to enforce the ASCE Code of Ethics that states, “Engineers shall hold paramount the safety, health, and welfare of the public and shall strive to comply with the principles of sustainable development” with those that are skeptical on such principles. A shortcoming that is especially serious because climate change raises many questions with ethical dimensions rooted in the human condition [18,19]. In this context, perhaps the suggestion of [20] for civil engineers to play a role in helping developing countries can help overcome some of that skepticism. Concerning the subfield of pavements although being one of the major civil infrastructures represents a small subset in the larger field of civil engineering. It is worth noting that according to [21], the total mileage of roads has reached 70 million kilometers. Still, other authors [22] are more modest mentioning that asphalt roads span a distance of more than three times around the sun (around 13 million kilometers). But that value can hardly be an accurate one because the United States alone has 6.5 million kilometers of roads [23]. This author also mentioned that asphalt pavements cover an area, in the order of magnitude, of Cuba or Iceland (100,000 km²). A search on the Scopus database for all publications concerned with civil engineering shows that in the beginning of the 80s, when publications about roads and pavements start to appear, other subfields of civil engineering already represented more than 700 publications per year (Fig. 1.1). Only in 1988 the number of pavement-related publications crossed 100 per year, still representing 0.8% of the civil engineering output. And only by 2004 research investigations in the field of roads and pavements were able to reach an accumulated number of more than 1000 publications that push that area to 1.6% of the civil engineering universe.

Figure 1.1 Evolution of the accumulated total number of publications (articles/reviews/chapters, books, and referenced conference papers) in Scopus affiliated with Civil Engineering Departments (gray line) and the keywords “Roads” or “Pavements” searched in the section title (black line).

Currently, the accumulated number of Scopus publications concerned with civil engineering exceeds half a million and the subfield of roads and pavements still represents less than 2%. Fig. 1.2 shows that in the subfield of publications concerning roads and pavements, the first publications concerned with sustainability appeared only in 2003. And only 7 years later the accumulated number of those publications reached 100. In 2018 the accumulated number of publications concerned with environmental aspects of roads and pavements has not yet reached 8% of the publications of that area. As shown in Fig. 1.3, the sustainability-related publications of all areas of civil engineering started to appear only by 1985 but around 2010 they were able to surpass all pavements and roads-related publications and since then these have increased in an exponential mode. Meaning that many of the advances carried out in the field of civil engineering were directly for certain subfields alone [24–27]. Only in 1988 has the number of pavement related publication cross one hundred per year still representing 0.8% of the civil engineering output. And only by 2004 were the researcher’s investigation in the field of roads and pavements able to reach an accumulated number of more than 1000 publications that push that area to 1.6% of the Civil Engineering universe. This fact by itself constitutes a strong justification for this book. Concerning the sustainability of pavements, several issues merit an especial concern.

Figure 1.2 Evolution of the accumulated total number of publications (articles/reviews/chapters, books, and referenced conference papers) in Scopus affiliated with Civil Engineering Departments having the keywords “Roads” or “Pavements” in the title (gray line) and the k...

Table of contents

• Cover image
• Title page
• Table of Contents
• Copyright
• List of contributors
• 1. Introduction to eco-efficient pavement materials
• Part 1: Pavements with recycled waste
• Part 2: Pavements for climate change mitigation
• Part 3: Self-healing pavements
• Part 4: Pavements with energy harvesting potential and vehicle power charging ability
• Index