The 2012 Olympics and Recycled Concrete
Introduction
Mention the phrase demolition to just about anyone and the scene that immediately comes up is a vision of a structure being blown up and collapsing to the floor. A lot of people have said they would really like to press the button, to trigger the explosive systems which will bring a disused property to the ground. On many occasions the thing that comes down, must go up and now we are seeing many old properties being razed to help with making way for potential future development, normally together with a regeneration project.
For companies that over several years have built their business surrounding the demolition of buildings, the demolition industry is now much more reaching than simply demolishing outdated buildings. After the structure is demolished the tremendous task of site clearance begins and in a community where consideration of the environmental impacts are ever increasing on most peoples agenda, the material remains provided by demolition must be separated for recycling purposes. This will include such resources as steel, wood, plastic, brickwork and concrete.
The vast majority of the materials are bulked up and shipped to the appropriate recycling plants for reprocessing. Materials such as bricks and concrete are generally crushed and become a recycled concrete aggregate product available for reuse in the construction of new roadways or buildings. Increasingly though, by means of breakthroughs in technological development, derivatives such as rubble to be recycled have to meet an extremely high standard for reuse in construction projects.
When crushed, the assorted sizes of recycled aggregate will govern the future usage potential of the product. Large sizes could possibly be utilised as ornamental rockery products in landscaping whilst much finer, almost shingle like product can be utilised as a bedding for pipe laying or as a layer in highway construction. With an ever-increasing amount of opportunities identified for the reuse of recycled aggregate, the entire demolition and construction industry is building a significant contribution to sustainable development. Following demolition of a site, many demolition contractors have expanded their service offering to include site clearance services.
Reasons For the Increased Focus on Recycling from Construction and Demolition Projects
In 1996, UK Government added a levy on all waste items going to landfill. The duty is paid out on top of typical gate rates for waste materials being disposed in landfill and since its initial release the price has risen annually. When it was first introduced, the standard rate of tax for general waste products being sent to landfill was �7 per tonne and �2 per tonne for inert substances. The tax was created to encourage commercial and industrial organisations and local authorities collecting from properties, to divert waste away from landfill for recycling. In April 2009, the standard rate of landfill duty increased to �40 per tonne and it is timetabled to rise annually by �8 per tonne until 2013. The reduced level of tax charged upon any inert materials going to landfill including concrete and soils, has remained comparatively stable recently and is currently at �2.50 per tonne.
Even so, the weight factor alone of a bulk load of those inert products going straight to landfill will guarantee that the full cost of disposal becomes extremely expensive and so even in the demolition and construction sector, diverting waste from landfill is a top priority.
Some demolition contractors will offer cheap crushed stone just to move it off their premises.
Next time you see a demolition project in progress or pass just about any construction site during a build programme, it is obvious to see the quantity of waste materials being created. If waste material isn’t in skips, piles of rubble will probably be stacked high. The placing of rubble waste materials in skips has been a significant issue for waste companies for quite some time. I have worked within the waste sector, I have seen skip lorries tipped backwards with the cab of the vehicle up in the air, a result of the sheer overloading of waste skips with building site waste.
Each year, the uk generates around 330 million tonnes of waste and approximately 90 million tonnes of this is coming from construction and demolition wastes. This figure has remained reasonably constant since 2001. About two thirds of this waste is normally recycled or reused in land reclamation or agricultural improvement projects. Since the later part of the 1990s there’s been a gradual rise in the volumes of construction waste being recycled and this has been helped by improvements in technology that have led to improved crushing products to create more frequent use of various specifications of recycled aggregates. There’s been a real focus upon the United Kingdom construction industry to encourage greater recycling of waste material on site.
In the past few years, the construction sector as a whole has worked hard to encourage construction site managers to place a greater focus upon recycling on site. This has triggered a growth in the recycling of all inert materials from site.
Before the introduction of the landfill tax all construction site waste including bricks and concrete was bulked up and moved to a landfill site for disposal. No regard was given to recycling. Nowadays there are stringent restrictions across the sector, in conjunction with an increase in environmental awareness, as well as the commercial benefits in making certain that this type of waste is recycled. Addititionally there is significantly greater recognition of the wide array of business opportunities to use recycled aggregates in the construction process on alternative construction projects or in fields such as landscaping or home and garden Do-it-yourself. Following the demolition process, together the waste concrete, bricks, masonry etc will probably be transformed into a recycled concrete aggregate.
To recycle concrete aggregate to a high grade and resalable product, it needs to be totally free of other contaminants such as wood, paper, card, steel and other general waste materials. The end product must comply with the requirements of British Standard BS 8500. The process of recycling the concrete can usually be achieved in one of two ways. Some demolition companies will locate a crushing device on the demolition site, whereas some contractors will prefer to carry the waste to be recycled, back to their premises for segregation for recycling or re-use. On projects where demolition and new construction is to take place at the same site, the contractor is very likely to locate a crushing appliance on site to escape incurring extra transportation costs in taking the materials back to a sorting and crushing facility. There is now very sophisticated crushing equipment on the market to reduce concrete to a very fine specification.
There are lots of legal and environmental issues that midlands demolition contractors should now follow when undertaking their projects.
The Growing Interest in High Quality Recycled Aggregate
Before commencing the crushing process, it needs to be determined what the end product will be used for to make sure the recycled aggregate is to meet the required standards. There’s huge requirement for recycled aggregate to be used back in the construction process. As a product, recycled concrete aggregate can be utilised for almost any kind of concrete structural function, road surfacing or pipe laying project. Having passed through the crusher the pieces of aggregate can be sorted by size. Bigger pieces can be retained as a decorative product for use in garden rockery projects, or they might be passed back through the crusher to be crushed to a smaller size. The small pieces of recycled aggregate may be suitable for use as a gravel on new construction projects, road laying or driveways at home. The crushing units are now capable of achieving good 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. Recycled aggregates have become a versatile reusable product and has eliminated the need for large volumes of a good material to be disposed of in landfill and therefore offer significant environmental benefits.
The need for top quality crushed aggregate is growing. There are key standards in position which are targeted upon improving the recycled concrete aggregate industry. By means of research and improvement, more widespread applications are being identified for the employment of recycled aggregate. No more is concrete, just concrete. What we are talking about now are many different grades of recycled aggregate, which range from the large chunks of aggregate to very specific 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 utilised in road construction or at home on driveways. As well as being employed as a mix for highway construction, recycled aggregate is being used as bedding for pipe laying or base material prior to construction projects starting. In achieving such good quality grades the 20-5mm recycled aggregate can be utilised as an aggregate base in highway construction and the quality meets the standards necessary to allow its reuse in concrete production. The 20-5mm recycled aggregate is a very versatile product.
On the list of important criteria when using recycled aggregate is selecting the right specification for the task. For instance, when making use of 20-5mm coarse graded aggregate for a highway foundation, the thickness of the layer demanded will have to be determined to tolerate traffic flows. Traffic flow on a motorway will be significantly different to that of a country road. One good reason aggregate produced to a 20-5mm specification is used as a road base is that it assists good drainage. Once the recycled aggregate is laid, appropriate layers of asphalt or concrete can be laid across it to construct the road surface.
In recent years, in the United Kingdom we seem to have more rain than sunshine and therefore the selected aggregate must have the ability to tolerate variances in temperature and conditions e.g. dampness for very long periods, torrential downpours, long dry spells. With its good waterflow and drainage characteristics, the recycled 20-5mm product is the ideal choice for a lot of sand and gravel applications including, pipe bedding, driveways and footpaths, landscaping, and also for use in ready mixed and precast concrete products.
In matters as complex as demolition it is advised to retain a specialist company conversant with BREEAM and other demolition legislation www.eastmidlandsdemolition.co.uk is one such company that comes highly recommended.
Recycled Aggregates and the 2012 Olympics
In its bid for the 2012 Olympic Games, London set sustainability as the focal point of its bid. The bid team recognized a major opportunity to increase awareness of climate change and the issues that surround it, and bring it to the World’s notice. With the eyes of the Entire world observing, the Olympic Games present an exceptional opportunity to put across key points with regards to sustainability. Throughout the entire development of the Olympics project, there is a commitment to make 2012 by far the most sustainable Olympic Games ever held. This focus originated when preparing the design and build programmes for the facilities and venues, the transport links and network, the hosting of the Games themselves and will end by leaving behind a long lasting heritage of a sustainable natural environment.
Ever since London was awarded the Games, all suppliers involved in the development specifications, from the construction of the Olympic Arena, the Olympic Village and transportation links between the venues have been focused upon ensuring the use wherever possible of sustainable materials. Throughout the entire Olympic build programme construction managers have worked hard to locate acceptable sustainable materials for use in the build programme. By the end of the whole project we will see some clearly visible 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 numerous sites will not even think about how recycled aggregates have been specified as part of the overall construction project. However developers and specifiers of materials for use within the build programme will be secure in the knowledge that they have selected sustainable products which include, the most suitable recycled concrete aggregates as part of the project. With its identified characteristics, let us hope that somewhere in the world wide Television coverage the 20-5mm recycled aggregate gets a mention somewhere, somehow.
Summary
How times have developed in recent years for the demolition and construction industry. Organisations have had to adapt to meet demanding environmental conditions. As with virtually any sector, new regulations and legislation determine the benchmarks to which your business must aspire, if it is to be successful.
Firms involved in the production of recycled concrete aggregate are no different. These are classed 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 crucial 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 supplying 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 road construction and driveways. The demolition and construction industry now places sustainability at the forefront of its future development projects.
