Concrete Construction and Sustainability

The paper provides a detailed discussion on the design and implementation of concrete construction projects to minimize environmental impact of buildings and public works projects during the conception, construction and operation including maintenance. It will help engineers and architects appreciate and utilize concrete building systems to design high performance buildings that conserve energy and maximize occupant's comfort, thus highlighting the contributions of our profession to the sustainability. This paper discusses many aspects of sustainability and concrete industry emanating from the US experience with various professional organizations, personal experience and the prospect of using it to the sustainability in India.

In the US, there have been efforts in education in construction industry management (CIM) which offers sustainability in education, a very important task of four profession. The attributes that concrete has to offer the green building movement and the effect that emerging information on life cycle analysis has on concrete's role in this important revolution to the building industry, which is applicable and useful information in Indian scenario. This paper outlines aspects of this important and holistic research work currently being undertaken by the authors to develop handbook to fulfill the need of the industry as well as professionals and in the education for Concrete Industry Management Program, a four-year degree program currently offered at five universities in the US and can be expanded globally either through direct cooperation or long-distance learning, which is the upcoming feature and needs its application in civil engineering.

Introduction

This paper is a special privilege to present in 2009 as a Lecture at the ICI Annual General Meeting. With the theme of the meeting being Green Structures for Sustainability, I could not resist a little diversion and take the opportunity to review "sustainability" in construction industry on a broader basis. In doing so, I want to bring the attention of the technological advances during the last decade that have affected our lives at all stages.

While sustainability has become the buzzword in our daily life, one should be glad that we are all made aware of this phenomenon for the mankind to realize its importance in our life. It is widely recognized that definitions of sustainability vary considerably based on the reference basis. These definitions and perceptions as they relate to the built-environment are important to understand the scope of the industry's commitment. On a broad basis, sustainable development is development that meets the needs of the present without compromising the ability of future generations to meet their own needs. In essence, sustainable development is a process of change in which exploitation of resources, the direction of investments, the orientation of technological developments and institutional changes are all in harmony and enhance current and future potential to meet human needs and aspirations."[1]

There are many viewpoints on sustainability; the most perspectives emphasize socio-economic concepts associated with sustainability, along with an emphasis on holistic long-term life-cycle considerations.

Within a broad societal context sits the built-environment, the infrastructure that concrete helps to shape. According to Brandon, P.S., Lombardi, P. (2005) in their text, Evaluating Sustainable Development in the Built-environment, this environment is generally defined as "…the built-environment…and is concerned with humankind's activity in creating shelter and accommodation for itself, an act which inevitably changes the environment in some way. In particular the development of cities, and the underlying social cohesion and culture which is created through cities, has a big impact on the use of resources, the way people behave, their interaction with nature and the waste products that ensue from this type of living."

The main actors in the North American concrete industry as it has historically been thought of are heavily concentrated in the "production" category above. The place of the construction industry (and the concrete industry that is a component of it) in this big picture of sustainability has already been recognized.

There are many initiatives that concern the built-environment and infrastructure, which could be beneficially influenced by the optimum use of concrete. From this analysis it is recognized that there is an environmental abatement versus growth paradox for the industry. The new and retrofit construction proposed is likely to increase demand for concrete, compounded potentially by a greater use of concrete per structure. This reinforces the need for the industry to drive down the environmental footprint of its product, but also to work urgently to drive down the future environmental costs of maintaining and operating our infrastructure over cradle-to-cradle lifecycles.

This paper has several aspects to cover the large spectrum of sustainability, which all lead to the topic on hand. At the end I hope to draw some conclusions as to how we in ICI and as Concrete Interested Individuals achieve our goals.

Sustainability Globally Speaking

We have come a long way on sustainability around the globe. As our world has become smaller and technology has grown leaps and bound, we cannot ignore what is happening in the world and think only of one country as in the past. A little search on Internet brings out much more information than we ever did. Thus, when we consider sustainability in a broad sense globally, we must see what is taking place in various parts of the world.

The World Business Council for Sustainable Development (WBCSD) seeks to illustrate how companies work independently, or with different stakeholders, to integrate the challenge of sustainable development into their business activities. This is vary important since it brings out sustainability not just in the context of our field but in an overall responsibility of economic improvement. There are more than 100 case studies are currently available on-line. The couple of relevant studies are illustrated here to make the point.

Case I: Reducing raw material and fossil fuel use in cement production by Castle Cement, UK (part of Heidelberg Cement Group). They meet about a quarter of the demand for cement in the United Kingdom, selling more than three million tons of the products. Castle has substantially reduced its use of virgin raw materials and fossil fuels in recent years. In 2003-4, Castle used over 195,000 tons of alternate fuels to replace approximately 160,000 tons of coal in its kilns. Energy has been recovered from scrap tires, Cemfuel (processed from the residues of recycled waste solvents), and Profuel (paper and plastic wastes not viably recycled in other ways). Now, uniquely in the UK, Castle has introduced (Footnotes) a biomass fuel Agricultural Waste Derived Fuel (AWDF), which is meat and bone meal, produced by sterilizing and grinding abattoir waste. Castle continues to use alternative raw materials prolonging the life of the company's quarries. Pulverized fuel ash has been widely used, while other recycled materials include waste plaster moulds from the ceramic industry.

Case II: Sustainable products for the construction industry by SCOTASH, a joint venture (JV) between energy company Scottish Power and Lafarge Cement UK.

The company takes the ash output from Scottish Power's coal-fired power stations and re-engineers it into sustainable products for the construction industry. Environmentally friendly products from ScotAsh are used in the construction of roads, buildings, windfarms, harbors and other major projects throughout the UK, and demand for specialized materials, such as environmental binders and concrete enhancers, continues to grow. (Scottish Power's coal-fired power stations produce around 600,000 tons of ash each year. Until recently, much of this was disposed of to ash lagoons. Now, the majority of Scottish Power's ash output is recycled in Scot Ash products. Using pulverized fuel as (PFA) in cement and concrete enhances their long-term strength, durability and resistance to chemical attack. PFA is also used as a simple fill material, as a grout to repair or stabilize buildings or structures, and as a lightweight aggregate. Eventually, ScotAsh aims to recycle Scottish Power's entire ash output. With over 80% achieved in the last year, that target is now within reach.

Expertise in Civil Engineering is indispensable for realizing a sustainable society in which a comfortable living environment for humans is compatible with a high-quality natural environment. Environmental is one of the basic field, we use for planning and constructing the infrastructure for water supply, sewerage and waste treatment systems.

In Japan at Hokkaido University (HU), they established a new program "The Sustainable Metabolic System of Water and Waste for Area-Based Societies," which is commended as the world's leading research project of its kind. This program is based on the recognition that to achieve a sustainable society, an area-based society, including river basins and coastal waters, needs to serve as the basic unit of human activities. Aiming to keep living environments in an area-based society safe and comfortable and minimize the burdens that urban areas place on the natural environment, the project seeks to establish the sustainable metabolic systems of water and waste in the area-based society. To this end, we are tackling the various technological developments: Leading-edge water and wastewater treatment systems using membrane filtration, Resource recovery technology from waste material, Appropriate disposal system for solid waste, Construction material with long life, Repairing method of infrastructure to keep its long life, New management procedures of infrastructure considering reduction of the environmental/health risk, Reduced consumption of resources/energy, and demand of the people.

On the basis of the research outcomes, the program aims to produce researchers and engineers who can build up the sustainable area-based society with new infrastructure based on the concept of the holistic path and creates the whole system by integrating autonomous sub-systems. The program will establish an international center for education and research of New Socio-Environmental Engineering.

This brief global sustainability perspective takes us to civil engineering as a countrywide phenomenon and its progress and future.

Sustainability and Civil Engineering

In the US scenario, sustainability has been there all the time as everywhere else. In the last two decades though, it has caught up the attention of various professions, including politics. And, this made even more impact on our life. The writer became aware as he was in the process of constructing his own house5 from scratch and had never liked the wood or so called "stick-house," made of 2x4 in wood sections or even plywood at times. So, the "Green House" that he and his wife built in Silver Spring, MD which became them a little recognition and award(s), but it did not catch fire in the industry. It still pretty much is the same after ten years' pitch to many other folks. When he was the officer in the ASCE in 1995-98, ASCE approved the Policy No. 419 related to sustainability and has been accepted with many changes to become a very good direction for our profession. Known as Policy 419, ASCE believes that sustainable development is the challenge of meeting human needs for natural resources, industrial products, energy, food, transportation, shelter and effective waste management while conserving and protecting environmental quality and the natural resource base essential for future development. Sustainable development requires strengthening and broadening the education of engineers and finding innovative ways to achieve needed development while conserving and preserving natural resources.

Sustainability and Concrete Industry Developments

Concrete and its components and composites have been studied by various individuals and by institutes in many forms. At this point it is worth taking a broad look at the inputs and missions of various institutes, such ACI, PCI, PCA, NRMCA, PCI, etc. Sustainable development related to concrete is not just the carbon dioxide and potential for global warming, but should include the social, economic, and environmental aspects of how we use our resources.

ACI has been involved in sustainability efforts since 2000 when the Task Group on Sustainable Development was formed and ACI became an early member of the U.S. Green Building Council. ACI now has committees on sustainability both at Board level and at technical activities level. ACI hosted a workshop in the fall 2008 and spring 2009 conventions at the request of the Chair of ISO/TC 71 Subcommittee 8, Environmental Management for Concrete and Concrete (Structures, to further explore the issues relating to concrete, sustainability, and standardization and will hold another one in Fall 2009 convention.

Engineers understand the numerous social, environmental, and economic benefits of concrete. They know concrete is readily available and regionally produced; it is versatile and cost effective with a lower ecological cost; and, when designed and constructed properly, extremely durable and long lasting. So it is disappointing to see that there is constant challenge about concrete's carbon footprint and the intense energy needs to produce cement. Every material has its benefits and detriments. Every profession must be involved in sound practices of sustainable development using concrete including owners, architects, developers of rating systems and legislators. And the industry must also be proactive in mitigating the environmental shortcomings of concrete. ACI efforts are centered on providing sound and credible technical information on concrete and how it can be used to create a sustainable built environment.

ACI new strategic plan for the first time includes sustainability as one of its primary goals. The second of five goals states, "ACI will lead efforts that position concrete as sustainable and environmentally friendly." The plan calls for expanding understanding of the sustainability issue among membership, expanding resources to support sustainability issues, increasing the content on sustainability in ACI documents and products, and improving the perception of concrete relative to sustainability. ACI role in this effort is to identify issues, problems, and opportunities; to involve ACI members and the concrete industry in the development of technical information, and to inform concrete benefits to non-members from the construction industry and the public. ACI recognizes that construction with concrete is essential to developing a sustainable built environment.

Precast/Prestressed Concrete Institute (PCI) believes that precast concrete has inherent sustainable qualities and therefore the precast concrete manufacturers have a unique opportunity and obligation to participate in the sustainability movement by supporting green building practices and by continually improving their plant practices to reduce their environmental impact. As the voice of the precast concrete industry, PCI has established a sustainability committee to provide leadership through education, sharing of green building practices using precast concrete technology, and best practices in the plants. PCI oversees a certification program that ensures quality and standardizes practices for precast plants and erectors. A key initiative of PCI and its sustainability committee is the development of similar guidelines for sustainable practices, including water recycling and minimizing water use, dust and emissions control, and energy reduction.

Precast concrete contributes to Sustainability or green building practices in significant ways. The low water-cement ratios possible with precast concrete at 0.36 to 0.38 mean that it can be extremely durable. The thermal mass of concrete allows shifting of heating and cooling loads in a structure to help reduce mechanical-system requirements. Precast concrete is generally factory-made, there is little waste created in the plant (most plants employ exact-batching technologies) and it reduces construction waste and debris on site, reducing construction IAQ concerns. The load-carrying capacities, optimized cross sections, and long spans possible with precast concrete members help eliminate redundant members, and concrete readily accommodates recycled content.

Sustainability and Concrete Industry

The National Ready Mixed Concrete Association (NRMCA) strives to transform the built environment by improving the way concrete is manufactured and used in order to achieve an optimum balance among environmental, social and economic conditions. The ready mixed concrete industry is dedicated to upholding the principles of sustainable development that meets the needs of the present without compromising the ability of future generations to meet their own needs by attempting to balance social, economic and environmental impacts. Sustainability has become part of the fabric of society. Corporations in every industry are shaped by their customers' desire to be more environmentally responsible. Companies that adopt sustainable practices will become preferred suppliers. While environmental performance, including greenhouse gas emissions, will be increasingly monitored and regulated, voluntary initiatives such as the one presented here will help achieve ambitious sustainability goals.

Construction industry stakeholders including project owners, designers, contractors and product manufacturers are especially affected by the challenges of sustainable development since the built environment has significant environmental, social and economic impact on our lives and planet. On one hand, our built environment provides us with places to live and work and contributes to a robust economy and societal needs. On the other, operating our buildings, houses and infrastructure consumes enormous amounts of energy and valuable resources. Building products require natural resources and energy to produce and transport. New construction projects can burden natural habitats.

The concrete industry is uniquely positioned to meet the challenges of sustainable development. Its products help improve the overall environmental footprint of the built environment. For example, high performance concrete wall and floor systems help improve energy performance of buildings. Light colored pavements reduce urban heat islands and minimize lighting requirements. Pervious concrete pavements reduce and treat storm-water runoff. Concrete is extremely durable and provides for long service life. And the industry continues to develop new sustainable products through research and development.

The concrete industry is dedicated to continuous improvement through product and process improvements. The industry continues to increase the use of recycled materials, including industrial byproducts, thus conserving valuable natural resources and reducing process energy required to manufacture concrete. The industry continues to explore new ways to further reduce carbon footprint through the development of innovative cements and concrete mixtures. Concrete companies also strive to improve manufacturing processes, including the use of alternative energy sources, to minimize the energy of production and associated greenhouse gas emissions. Finally, the industry continues to enhance transportation efficiency and delivery methods to reduce the environmental impact of the construction process.

The NRMCA Initiative on Sustainability outlines goals for reducing the overall environmental footprint of concrete construction and provides strategies for achieving these goals. The concrete industry has been a key contributor in building this nation's infrastructure and will continue to enhance the sustainability of our built environment for generations to come.

Sustainability and Infrastructure

Highlights the shortcomings of infrastructure as it affects our lives are presented by Dr. Swamy very well. These are presented in his words: "There have been unparalleled advances during the latter half of the last century, to the scientific, engineering and social face of the world, but in that process, the world has also been plunged into several inter-related crises. In the context of the construction industry, these crises can be broadly classified in terms of environment, durability and sustainability. The crises have risen from a number of factors such as technological industrialization, population growth, world-wide urbanization, and uncontrolled pollution and creation of waste. There is now the real danger that the massive, indiscriminate and wasteful consumption of the world's material and energy resources may result in extensive global warming that is hard to reverse. The price for this environmental abuse is the rapid deterioration and destruction of the world's infrastructure, water shortages, environmental disasters, and material/structural deterioration by the forces of nature.

Every crisis experienced in the world has a direct impact on the construction industry, and since the construction industry is closely interlinked with energy, resources and environment, irredeemable environmental degradation can only be prevented by sustainable development of the industry, which alone can give hope for a better world and better Quality of Life. This paper advocates a Holistic approach to design and construction integrating all aspects from conceptual design to completion and maintenance during service life."

In the US, the ASCE Report continuously grade America's Infrastructure. They estimate a five-year total investment need of US $1.7 trillion (2007), just to put back the roads, bridges, dams, drinking water and other infrastructure systems to good serviceable life. The average state of America's infrastructure was given a Grade D - Poor. As a specific example, some 40% of more than 500,000 highway bridges are rated as structurally deficient or functionally obsolete. Some $100 billion is the estimated requirement to eliminate current backlog of bridge deficiencies, and maintain repair levels." The things have changed not much better in 2008 ASCE report and in some respects has even worsened.

Life cycle is an important aspect of sustainability in concrete industry. When designing a building to minimize environmental impact, it is important to look at the complete life cycle of the building including material acquisition, manufacturing, construction, operation, and reuse/recycling. This is called the "cradle to cradle perspective." All phases of a building or product should be considered. Simply looking at the acquisition and manufacturing phases ignores impacts during the operational phase. Reuse/recycling considers new options once the product or building has reached the end of its service life. Its successful integration with the virgin material in construction enhances the industry but also helps appreciate the material much beyond the value that it demonstrates.

Sustainability and Engineering Education

The concept of Sustainable Development attempts to balance social, economic, and environmental impacts or what is commonly referred to as the "Triple Bottom Line." As such, sustainable development attempts to integrate these perspectives on how we live and how we affect the world around us by taking into account local, regional and global impacts. These attempts led to curriculum development, which recognizes the need for sustainable concrete development that has been discussed so far.

The project of Handbook/Textbook for Sustainability and Concrete Construction has been launched by the author (s) in the US, which is in its final stage of preparation. The book was initiated as an activity to develop a text for a course in Sustainability and Concrete Industry as part of the Construction Industry Management (CIM) initiative by the concrete industry at four universities. It soon became evident that the book could best be developed with several individuals in this field of wide coverage. It should be an interesting book with viewpoints from world experts in their field to make this book as complete and as updated of the activities related to this field. Taylor and Francis have scheduled it for publication early 2010. It is anticipated that it will be a state of the art book with information and delivery system with hard copy as well as a CD Audio version of book with extensive bibliography.

Educational efforts are made by Concrete Centre in UK to offer free technical presentations in the clients' office. The Concrete Centre helps all those involved in the design and use of concrete to become knowledgeable about the products and design options available - with the minimum of effort. It is a receptacle for knowledge about the innovative ideas and products emanating from the concrete sector and is available for consultation as part of integrated supply chain teams where it sets out to help teams deliver the best solutions for clients.  As such, it embraces all of the principles set out in 'Rethinking Construction' and 'Accelerating Change' - reduction of costs, improvements in efficiency of designers and constructors, assistance with innovation and integration of the supply chain. It is funded by 15 major cement and concrete organizations and it works alongside the British Cement Association, The Concrete Society, and the ready mix and precast concrete industries to ensure an integrated approach from the concrete sector to technical support, research, education, training and information services. 

Their teams provide expert assistance, advice on concrete issues and solutions on a multitude of topics. The team consists of qualified engineers and architects, housing experts and contractors with years of experience. All are on-hand to pass on their knowledge, free of charge, provide bespoke project advice, offer support and guidance on concrete and advise on current thinking and new innovations. Their presentations are CPD-certified with approved learning outcomes. All presentations related to the issues about Sustainability are segmented into the following related areas and some details of these courses:

1. Architecture
2. Building Structures
3. Civil engineering
4. Construction
5. Sustainability
6. Specification
7. Concrete technology

Sustainability

Definition of sustainability; concrete's initiative to become industry leaders; introduction to legislation; material credentials and inherent benefits; responsible sourcing; specification options; embodied/in-use energy; life-cycle performance; achieving holistic design; current case studies; resources.


Explanation of Principles and design techniques; future use in rising temperatures; passive solar design; embodied and in-use CO₂ emissions; case studies.

Some Examples

There are many examples that can be cited here and were also pointed out earlier. This section focuses on the total concept of sustainability.

The Orchid is located in the heart of rapidly growing suburbs with the domestic airport virtually in its backyard. In a polluted city like Mumbai, having won the accolade of being the most eco-friendly hotel is no easy achievement. It displays a heightened level of environmental sensitivity in its revolutionary architecture, design and interior decoration. Rehabilitation of the site, which originally included an old building, provides an interesting backdrop for this leading environmental business. The Orchid is flanked by drip irrigated greenery on either side providing the much needed break from pollution. The hotel while rather ordinary on the exterior includes one of the largest array of environmental technologies ever assembled in a hotel building. Double glass doors open into an imposing 70-feet tall fiber fountain. Passive solar design including a rooftop pool to reduce heat loads on the structure is coupled with adequate day lighting via a central atrium. Triple glazed windows, an anomaly in most of Asia, provide increased thermal and acoustic insulation. The building is constructed from a variety of low resource construction materials and is finished with low-VOC paint. Guests are treated to a host of environmental products from recycled paper guest programs to herbal amenity products. A revolutionary eco-button allows guests to participate in the environmental activities by reducing their air conditioning uses. There are two special guestrooms for the physically challenged people.

Employees and management are actively engaged in the environmental operation of the hotel. Over 10,000 local students have been educated on the environmental features of the hotel. Employees have developed a CD that illustrates and educates viewers on the environmental design and performance of the hotel. And the director has spoken at numerous seminars about the environmental virtues of the project. The Orchid's commitment to environmental excellence is evident everywhere in the hotel. The property's mantra is "Deluxe need not disturb, Comfort need not compromise and Entertainment need not be insensitive."

Second case study is the township in Masdar City in Abu Dhabi covers not just green building and concrete but considerably imbibes more green concepts. It is the most ambitious sustainable development in the world; when completed it will be the world's first zero carbon, zero waste city powered entirely by renewable energy sources. This important Initiative is backed by the long-term strategic commitment from the government of Abu Dhabi to accelerate the development and deployment of future energy solutions. This allows sustainable development and living to a new level.

The City is a clean-tech cluster, which is already attracting the world's best in all areas of sustainability from renewable energy to biomass. All types of companies from innovators, incubators, research and development, pioneers and solution providers will be part of the journey to create, work and live in Masdar City. It will be built over seven years at an investment in excess of US$20 Billion. Its master plan design meshes the century-old learnings of traditional Arabic urban planning and architecture with leading-edge technologies to create a sustainable, high-quality living environment for all residents. The City will be built in seven carefully designed phases, incorporating the latest technological advances generated in its clean-tech cluster and globally. The first buildings under construction already demonstrate the innovative vision: Masdar headquarters building will receive its power required for construction from a vast PV array on its roof built ahead of the remaining structure – a world-first.

Utility services at the City will include energy, district cooling, wet utilities (water, wastewater, re-use water, and storm water), Tele-communications and waste management. Infrastructure support projects at the City will include landscaping, common areas, leisure areas, access roads, bridges, tunnels and Information and Communication Technology (ICT) services as well as development management. To accomplish its ambitious endeavor, Masdar requires access to leading edge thinkers and companies through mutually beneficial partnerships. Masdar is currently embarking on a global drive to attract industry partners to participate in this historic endeavor.

As the first major hydrocarbon-producing economy to take such a step, Abu Dhabi has established its leadership position by launching the Masdar Initiative.The Masdar Initiative driven by the Abu Dhabi Future Energy Company (Masdar), a wholly owned subsidiary of the Mubadala Development Company (Mubadala) is a global cooperative platform for the open engagement in the search for solutions to some of mankind's most pressing issues: energy security, climate change and the development of human expertise in sustainability.

Abu Dhabi is leveraging its substantial resources and experience in global energy markets into the technologies of the future. One key objective of Masdar is to position Abu Dhabi as a world-class research and development hub for new energy technologies, effectively balancing its strong position in an evolving world energy market. A related objective is to drive the commercialization and adoption of these and other technologies in sustainable energy, carbon management and water conservation. In doing so, Masdar will play a decisive role in Abu Dhabi's transition from technology consumer to technology producer.

The goal is to establish an entirely new economic sector in Abu Dhabi around these new industries, which will assist economic diversification and the development of knowledge-based industries, while enhancing Abu Dhabi's existing record of environmental stewardship and its contribution to the global community.

Conclusion

There is work done in Sustainability presently on all fronts of the concrete industry. On a realistic basis, we are only seeing the tip of the iceberg and lot more needs to be done. This paper obviously sets the tone for some accomplishments, but also indicates much more to come in this important field, which will last for longtime in the history of mankind. In India for organisation like ICI we need to learn from global experiences and do our share to become a sustainable International Concrete Institute (ICI) as a leader and the follower.

References

• Sustainable engineering practice: an introduction by ASCE Committee on Sustainability, Jorge Vanegas, Published by ASCE Publications, 127 pages, 2004.
• Various documents from US organizations related to concrete available in the full form from the directly.
• http://www.aiche.org/IFS/Press/oct06newsletter.aspx
• http://www.sustain.hokudai.ac.jp/researchers_in_network/norihito_tambo/index.php
• The Concrete Centre, (Riverside House (4 Meadows Business Park (Station Approach (Blackwater (Camberley (GU17 9AB, Email: enquiries@ concretecentre.com
• http://www.toodoc.com/orchid-hotel-mumbai-ebook.html
• Appendices: Policies and Support from Various US Organizations
• ASCE - Civil Engineering
• https://www.asce.org/pressroom/news/policy_details.cfm
• http://content.coprinstitute.org/files/pdf/ASCEPolicyStatementSustainableDevelopment.pdf
• ACI – Concrete; www.concrete.org
• NRMCA - Ready Mix Concrete Industry – www.nrmca.org
• PCA - Cement Industry – www.pca.org
• PCI - Prestressed and Precast Concrete Industry – www.pci.org

Acknowledgement

The article has been reproduced from the proceeding of "National Seminar on Green Structures for Sustainability" with the kind permission from the event organisers.