The 2012 Olympics and Recycled Concrete

Published by Frank on October 15, 2010

Introduction

Mention the word demolition to almost any person and the picture that promptly comes to mind is often a vision of a structure being blown up and collapsing to the floor. A lot of people have claimed that they would love to press the button, to trigger the explosive devices that bring a disused building to the floor. On most occasions what comes down, must go up and now we are witnessing many dilapidated buildings being razed to make way for potential future development, normally within a regeneration project.

For businesses who over many years have built their business surrounding the demolition of architectural structures, the demolition sector has become far more reaching than just blowing up unwanted buildings. As soon as the building is demolished the massive task of site clearance starts and in a world where consideration of the environmental impacts are very high on most peoples agenda, the material remains as a result of demolition should be sorted for recycling applications. This will include such materials as steel, wood, plastic, brickwork and concrete.

A lot of the materials are bulked up and transported to the appropriate recycling plants for reprocessing. Materials such as bricks and concrete are usually crushed and converted into a recycled concrete aggregate product ready for reuse in the construction of new roads or buildings. Increasingly though, via advances in technological development, residues such as rubble to be recycled have to meet a very high standard for reuse in construction projects.

When crushed, the different sizes of recycled aggregate will determine the likely usage potential of the product. Large sizes could be employed as cosmetic rockery products in gardening whilst much finer, shingle like product can be utilised as a bedding for pipe laying or as a layer in highway construction. Through an increasing variety of possibilities identified for the reuse of recycled aggregate, the entire demolition and construction market is making a substantial contribution to sustainable development. Following demolition of a site, many demolition contractors have expanded their service offering to include site clearance services.

Reasons Behind the Increased Concentration on Recycling from Construction and Demolition Projects

In 1996, UK Government imposed a tax on all waste products going to landfill. The tax is paid in addition to normal gate fees for waste being disposed in landfill and since its initial release the charge has risen on an annual basis. When it was first introduced, the typical rate of duty for general wastes being sent to landfill was �7 per tonne and �2 per tonne for inert products. The levy was created to motivate commercial and industrial companies and local authorities collecting from properties, to divert waste away from landfill for recycling. In April 2009, the standard level of landfill duty grew to �40 per tonne and is scheduled to rise annually by �8 per tonne until 2013. The lower rate of tax charged upon any inert materials going to landfill like concrete and soils, has remained fairly steady recently and is presently at �2.50 per tonne.

Even so, the weight factor alone of a bulk load of those inert materials going directly to landfill will ensure that the whole cost of disposal becomes horrendously expensive and so even in the demolition and construction industry, diverting waste from landfill is a priority. The introduction of landfill tax has been a key driver in encouraging greater diversion of inert materials from landfill, to be used in sustainable development projects.

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Next time you see a demolition project happening or go past just about any construction site during a build programme, it is obvious to see the volume of waste materials being created. If waste material is not in skips, heaps of rubble will probably be stacked high. The placing of concrete waste materials in skips has been a significant problem for waste companies for many years. I have worked in the waste sector, I have seen skip lorries tipped backwards with the cab of the vehicle up in the air, because of the gross overloading of waste skips with construction site waste.

Each year, the uk produces close to 330 million tonnes of waste and approximately 90 million tonnes of this is from building and demolition wastes. This number has stayed fairly constant since 2001. About two thirds of this waste is usually recycled or reused in land reclamation or agricultural improvement projects. Since the later part of the 1990s there has been a steady rise in the quantities of construction waste material being recycled and this has been helped by improvements in technology that have resulted in improved crushing products to create more frequent use of various specifications of recycled aggregates. There has been a genuine focus upon the UK construction community to encourage greater recycling of waste on site.

In recent years, the construction sector in general has worked hard to persuade construction site managers to put a greater emphasis upon recycling on site. This has triggered a growth in the recycling of inert materials from site.

Prior to the introduction of the landfill tax almost all construction site waste including bricks and concrete was bulked up and moved to a landfill site for disposal. No thought was given to recycling. These day there are strict regulations across the sector, in conjunction with an increase in environmental awareness, and also the commercial benefits in making certain that this sort of waste is now recycled. Addititionally there is increased recognition of the vast array of business opportunities to use recycled aggregates in the construction process on new construction projects or in areas such as landscaping or home and garden DIY. Following the demolition process, together the waste concrete, bricks, masonry etc will probably be transformed into a recycled concrete aggregate. Recycling of aggregates has become a common process for demolition contractors.

To recycle concrete aggregate to a high standard and resalable product, it has to be totally free of other debris such as wood, paper, card, steel and other general waste materials. The final product must comply with the requirements of British Standard BS 8500. The task of recycling the concrete can typically be achieved in one of two ways. Some demolition companies will transport a crushing unit on the demolition site, whereas a lot of contractors will opt to transport the waste to be recycled, to their own premises for separation for recycling or re-use. On projects where demolition and new construction is to occur at the same location, the contractor is very likely to place a crushing appliance on site to avoid incurring extra transportation costs in taking the material to a sorting and crushing facility.

Many well-known Nottingham demolition contractors also have extended their services to add site clearance services.

The Growing Need for Top Quality Recycled Aggregate

Before commencing the crushing procedure, it needs to be determined what the end product is to be used for to make sure the recycled aggregate is to match the necessary standards. There’s huge demand for recycled aggregate to be used within the construction process. As a product, recycled concrete aggregate can be used for nearly every form of concrete structural function, road surfacing or pipe laying project. Having passed through the crusher the pieces of aggregate will be sorted by size. Bigger pieces can be retained as a decorative product to use in garden rockery projects, or they may be passed back through the crusher to be crushed to a reduced size. The smaller sized bits of recycled aggregate might be suited to use as a gravel on new construction projects, road laying or driveways at home. The crushing machines are now capable of achieving high quality small aggregate grades such as the production of a 20-5mm gravel which can be bagged and used in the garden at home or bought in bulk as part of projects involving new concrete production. The advances in technology mean that the recycling of aggregates for other uses such as a simple gravel product or for use in concrete products has greatly reduced the need to dig quarries to mine for gravel.

The demand for top quality crushed aggregate is increasing. There’s key standards in place that are targeted upon improving the recycled aggregate market. Through research and improvement, more widespread uses are now being identified for the employment of recycled aggregate. No longer is concrete, just concrete. What we are talking about now a wide range of distinct grades of recycled aggregate, which range from the large sections of aggregate to very precise 6f2 recycled concrete which can be used as a sub-base material for construction jobs, or 20-5mm recycled aggregate, which is a gravel and can be used in road construction or at home on driveways. In addition to being used as a mix for road construction, recycled aggregate is being used as bedding for pipe laying or footing material prior to construction projects commencing. In achieving such top quality grades the 20-5mm recycled aggregate can be utilised as an aggregate base in road building and the quality meets the specifications necessary to allow its reuse in concrete production.

On the list of important requirements when you use recycled aggregate is choosing the right specification for your task. By way of example, when making use of 20-5mm coarse graded aggregate as a road base, the thickness of the layer required needs to be determined to tolerate traffic flows. Traffic flow on a motorway is going to be significantly different to that of a country road. One good reason aggregate produced to a 20-5mm specification is commonly employed as a road base is that it aids good drainage. Once the recycled aggregate is laid, appropriate layers of asphalt or concrete can be laid above it to create the road surface.

Recently, in the United Kingdom we seem to have more bad weather than hot sunshine and as a consequence the selected aggregate must have the capacity to withstand variances in temperature and conditions e.g. dampness for long periods, torrential downpours, long dry spells. With its good drainage qualities, the recycled 20-5mm product may be the ideal choice for some sand and gravel applications including, pipe bedding, driveways and footpaths, landscaping, and also for use in ready mixed and precast concrete products.

The build programme for London’s Olympic Village, has specified the use of a clean recycled concrete aggregate crushed to a 20-5mm specification.

Recycled Aggregates and the 2012 Olympics

In its bid for the 2012 Olympic Games, London set sustainability as the focus of its bid. The bid team identified a significant opportunity to boost awareness of climate change and the challenges which surround it, and bring it to the Globe’s notice. With the eyes of the World watching, the Olympics provide a unique opportunity to communicate important messages with regards to sustainability. Through the entire growth and development of the Olympics project, there’s a commitment to make 2012 the most sustainable Olympic Games ever held. This focus began when preparing the development and build programmes for the facilities and venues, the transportation links and network, the hosting of the Games themselves and will end by leaving a long lasting heritage of a sustainable natural environment.

Ever since London was granted the Games, all companies involved with the development specifications, from the design of the Olympic Arena, the Olympic Village and transportation links to the venues have been encouraged upon guaranteeing the use wherever possible of sustainable resources. Across the entire Olympic build programme developers have worked hard to discover suitable sustainable materials for use in the build programme. At the conclusion of the whole project we will see some clearly obvious examples of the use of sustainable products.

Similarly there will be many more that are much less visible, and furthermore, many which will be not visible at all. One of those products which visitors to the games and its many sites won’t even consider how recycled aggregates have been employed as part of the overall construction project. But designers and specifiers of resources for use in the build programme will be comfortable in the knowledge that they have selected sustainable products which include, the most appropriate recycled concrete aggregates as part of the project. With its identified characteristics, let’s hope that somewhere in the global Television coverage the 20-5mm recycled aggregate gets a mention somewhere, somehow. Imagine being asked to supply recycled aggregate which meets a very specific 20-5mm clean material specification, to help build the 2012 Olympic Village.

Conclusion

How times have changed in recent years for the demolition and construction industry. Organisations have been required to change to meet challenging green conditions. As with almost any segment, new laws and legislation dictate the benchmarks to which your business must aspire, if it is to achieve success.

Businesses involved in the production of recycled concrete aggregate are not any different. These are generally categorised as processed materials and must conform to a particular product specification which can be used in the construction process. The standard BS8500-2 offers a full specification for the uses of recycled concrete aggregates in concrete, although with such a vast range of recycled aggregates an all encompassing specification for the use of these aggregates is yet to be determined. The most important thing is that the industry does not stand still and wait for the specifications to be finalised. The versatility of recycled aggregates means that demolition contractors operating crushing plants are seeking to identify markets through which to sell their recycled products. The advances in crusher technology and machinery has seen a big increase in the options now available in providing large chunks of recycled aggregate for landscape gardening use in rockeries, down to a gravel type 20-5mm recycled aggregate with its good drainage qualities for use in highway construction and driveways.