Handbook of Recycled Concrete and Demolition Waste

F. Pacheco-Torgal, Yining Ding, Fernando Pacheco-Torgal

• Publisher: Woodhead Publishing
• Year: 2013
• Print ISBN: 9780857096821
• eBook ISBN: 9780857096906
• Topic: Tecnologia e ingegneria
• Subtopic: Gestione ambientale

The civil engineering sector accounts for a significant percentage of global material and energy consumption and is a major contributor of waste material. The ability to recycle and reuse concrete and demolition waste is critical to reducing environmental impacts in meeting national, regional and global environmental targets. Handbook of recycled concrete and demolition waste summarises key recent research in achieving these goals.Part one considers techniques for managing construction and demolition waste, including waste management plans, ways of estimating levels of waste, the types and optimal location of waste recycling plants and the economics of managing construction and demolition waste. Part two reviews key steps in handling construction and demolition waste. It begins with a comparison between conventional demolition and construction techniques before going on to discuss the preparation, refinement and quality control of concrete aggregates produced from waste. It concludes by assessing the mechanical properties, strength and durability of concrete made using recycled aggregates. Part three includes examples of the use of recycled aggregates in applications such as roads, pavements, high-performance concrete and alkali-activated or geopolymer cements. Finally, the book discusses environmental and safety issues such as the removal of gypsum, asbestos and alkali-silica reaction (ASR) concrete, as well as life-cycle analysis of concrete with recycled aggregates.Handbook of recycled concrete and demolition waste is a standard reference for all those involved in the civil engineering sector, as well as academic researchers in the field.- Summarises key recent research in recycling and reusing concrete and demolition waste to reduce environmental impacts and meet national, regional and global environmental targets- Considers techniques for managing construction and demolition waste, including waste management plans, ways of estimating levels of waste, the types and optimal location of waste recycling plants- Reviews key steps in handling construction and demolition waste

1

Introduction to the recycling of construction and demolition waste (CDW)

F. Pacheco-Torgal, University of Minho, Portugal

Abstract:

The chapter starts with an overview on the recycling of construction and demolition wastes (CDW), followed by a brief analysis on the EU 70% recycling target for 2020. The chapter also includes a book outline.

Key words

construction and demolition wastes (CDW)

recycling

resource efficiency

waste management

life-cycle assessment (LCA)

1.1 Introduction

The high volume of construction and demolition waste (CDW) generated today constitutes a serious problem. CDW in the United States is estimated at around 140 million metric tons (Yuan et al., 2012). Eurostat estimates the total for Europe to be 970 million tons/year, representing an average value of almost 2.0 ton/per capita (Sonigo et al., 2010). It should be noted that the figures for CDW generation per capita in Europe have a wide geographical variation (e.g. 0.04 tons for Latvia and 5.9 tons for France). These figures must be viewed as lower estimates, as this type of waste is often dumped illegally. The data are also hard to interpret because of the different waste definitions and reporting mechanisms in different countries (Sonigo et al., 2010).

Recycling of CDW is of paramount importance because it reduces environmental pressure. It prevents an increase in the area needed for waste disposal and also avoids the exploitation of non-renewable raw materials. Environmental impacts caused by the extraction of non-renewable raw materials include extensive deforestation, top-soil loss, air pollution and pollution of water reserves. It should be noted that 40% of all materials are used by the construction industry (Kulatunga et al. 2006). Wang et al. (2010) records that construction in China consumes approximately 40% of total natural resources and around 40% of energy. During the last century, the use of global materials increased eight-fold. As a result, almost 60 billion tons (Gt) are currently used per year (Krausmann et al., 2009). It has been forecast that demand for materials will reach at least double the current levels by 2050 (Allwood et al., 2011).

In the context of housing life-cycle assessment (LCA), the environmental gains associated with the recycling of CDW constitute a very small fraction (just 3% in United Kingdom) of the total global warming potential (GWP). Ninety percent of the GWP relates to the use stage (Cuéllar-Franca and Azapagic, 2012). This situation is not confined to the UK residential sector and applies generally in Europe and in other parts of the world where high energy-efficient buildings are the exception (Pacheco-Torgal et al., 2013). However, the recast of the Energy Performance of Buildings Directive (EPBD), which was adopted by the European Parliament and the Council of the European Union on 19 May 2010, sets 2020 as the deadline for all new buildings to be ‘nearly zero energy’. This will dramatically increase the percentage (Pacheco-Torgal et al., 2013a).

The benefits of effective CDW recycling are economic as well as environmental. For example, the Environment Agency of the US (EPA, 2002) states that the incineration of 10 000 tonnes of waste can mean the creation of 1 job, landfill can create 6 jobs, but recycling the same amount of waste can create 36 jobs. The recent report Strategic Analysis of the European Recycled Materials and Chemicals Market in Construction Industry records that the market for recycled construction materials generated revenues of €744.1 million in 2010 and is estimated to reach €1.3 billion by 2016 (Frost and Sullivan, 2011). This is a low estimate as it does not take into account a near 100% CDW recycling scenario, which will be the future of construction (Phillips et al., 2011).

During the last 15 years, investigations in the field of CDW have focused on three major topics: generation, reduction and recycling. This is guided by the ‘3Rs’ principle (Lu and Yuan, 2011). However, as it is a more complex issue, zero-waste will demand a much wider approach requiring ‘strong industry leadership, new policies and effective education curricula, as well as raising awareness and refocusing research agendas to bring about attitudinal change and the reduction of wasteful consumption’ (Lehmann, 2011).

1.2 EU 70% recycling target for 2020

According to the revised Waste Framework Directive 2008/98/EC (WFD), the minimum recycling percentage of ‘non-hazardous’ CDW by 2020 (‘excluding naturally occurring material defined in category 170504 (soil and stones not containing dangerous substances) in the European Waste Catalogue’) should be at least 70% by weight (Saez et al., 2011; del Rio Merino et al., 2011). This target and also the communication A Resource Efficient Europe (COM, 2011) indicates the determination of the EU to emphasise the importance of recycling. As the current average recycling rate of CDW for EU-27 is only 47% (Sonigo et al., 2010), increasing it by 70% in just a decade seems an ambitious goal.

CDW are often used as aggregates in roadfill, constituting a down-cycling option. Worldwide aggregate consumption is around 20 000 million tons/year and an annual growth rate of 4.7% is expected (Bleischwitz and Bahn-Walkowiak, 2011). The environmental impact of primary aggregates includes the consumption of non-renewable raw materials, energy consumption and more importantly, the reduction of biodiversity at extraction sites. The cost of aggregates is dependent on transport distances and the price per ton doubles for every 30 km (Van den Heede and De Belie, 2012). Extraction operations therefore have to be near construction sites, which increase the number of quarries and the biodiversity impact. More than one-third of aggregate consumption is related to the production of concrete, which is the most widely used construction material, currently standing at about 10 km³/year (Gartner and Macphee, 2011). By comparison, the amount of fired clay, timber and steel used in construction represents, respectively, around 2, 1.3 and 0.1 km³ (Flatt et al., 2012).

Although the use of CDW as recycled aggregates in concrete has been studied for almost 50 years, there are still too many concrete structures made with virgin aggregates (Pacheco-Torgal and Jalali, 2011; Pacheco-Torgal et al., 2013b). This is due to their low cost, lack of incentives, low landfill costs and in some cases, a lack of up-to-date technical regulation (Marie and Quiasrawi, 2012). Recycled aggregates also contain impurities which can be deleterious in Portland cement concrete. It is therefore difficult for the concrete industry to use these materials unless uncontaminated recycled aggregates are used. This issue highlights the importance of developing new binders, which are more suitable for CDW recycling. The WFD 70% target increases the need for effective recycling methods and it is the purpose of this book to make a contribution in this area. It also addresses new techniques for the remediation and/or immobilisation of hazardous wastes such as asbestos and for CDW prevention/reduction, which remains the best option (EC, 2006).

1.3 Outline of the book

Part I is concerned with the management of CDW (chapters 2 to 6).

Chapter 2 considers waste management plans, reviews existing methods in several countries and presents the results of a wide survey assessing the effectiveness of the requirements in implementing waste management plans for the Hong Kong construction industry. Attitudes, benefits and difficulties related to the implementation of waste management plans are discussed.

Chapter 3 covers methods of estimating CDW and includes studies and tables to estimate the amount of CDW. Seventeen examples and case studies on the factors affecting such estimates, the improvement achieved in management scenarios and the benefits of its implementation are presented.

In Chapter 4, waste management plants and technology for recycling CDW are addressed. The types and choices of waste management plants are discussed. Particular attention is given to the health and safety of workers.

Chapter 5 covers the use of multi-criteria decision-making methods for optimal CDW recycling facilities.

Chapter 6 reviews the relevant economic issues in the management of CDW facilities.

Part II is concerned with the processing and properties of recycled aggregates from CDW (chapters 7 to 13).

Chapter 7 compares conventional de...

Table of contents

• Cover image
• Title page
• Table of Contents
• Copyright
• Contributor contact details
• Woodhead Publishing Series in Civil and Structural Engineering
• Chapter 1: Introduction to the recycling of construction and demolition waste (CDW)
• Part I: Managing construction and demolition waste
• Part II: Processing and properties of recycled aggregates from construction and demolition waste
• Part III: Applications of recycled aggregates from construction and demolition waste
• Part IV: Environmental issues affecting recycled aggregates from construction and demolition waste
• Index