The 2012 Olympics and Recycled Concrete
Introduction
Mention the term demolition to almost anyone and the image that promptly comes up is often a vision of a structure being blown up and collapsing to the ground. Lots of people have claimed they would really like to push the button, to detonate the explosive units that bring a disused structure to the ground. On most occasions what comes down, must go up and now we are witnessing many dilapidated properties being razed to make way for potential future development, normally together with a regeneration project.
For organizations that over a number of have developed their business within the demolition of structures, the demolition sector has become considerably more reaching than just demolishing unwanted buildings. After the structure is demolished the massive task of site clearance starts and in a world where consideration of the environmental effects are high on a good number of peoples agenda, the material remains provided by demolition need to be separated for recycling applications. This will likely include such products as steel, wood, plastic, brickwork and concrete.
Almost all of the materials tend to be bulked up and shipped to the appropriate recycling plants for reprocessing. Products such as bricks and concrete can be crushed and converted into a recycled concrete aggregate substance completely ready for reuse in the making of new roadways or buildings. Ever more though, via breakthroughs in technological development, derivatives like rubble to be recycled must meet a very high standard for reuse in construction projects.
When crushed, the varied grades of recycled aggregate will determine the likely usage potential of the product. Large sizes could be used as decorative rockery products in landscaping while much finer, almost shingle like product may be used as a bedding for pipe laying or as a layer in road construction. With an increasing number of possibilities recognized for the reuse of recycled aggregate, the whole demolition and construction market is generating 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 Behind the Increased Focus on Recycling from Construction and Demolition Projects
In 1996, UK Government imposed a duty on all wastes going to landfill. The duty is paid on top of normal gate charges for waste materials being disposed in landfill and since its initial release the charge has increased on an annual basis. When first introduced, the common rate of tax for general wastes being sent to landfill was �7 per tonne and �2 per tonne for inert products. The duty should inspire commercial and industrial organisations and local authorities collecting from households, to divert waste away from landfill for recycling. In April ‘09, the standard rate of landfill tax increased to �40 per tonne and is scheduled to increase each year by �8 per tonne until 2013. The reduced rate of duty incurred upon any inert materials going to landfill for example concrete and soils, has remained fairly stable in recent years and is currently at �2.50 per tonne.
Nonetheless, the weight of a bulk load of these inert products going directly to landfill will guarantee that the whole cost of disposal becomes extremely expensive and so even in the demolition and construction sector, diverting waste from landfill is a priority. The arrival of landfill tax has been a key driver in encouraging greater diversion of inert materials from landfill, to be used in sustainable development projects.
Advancements in crushing machinery technology now allows recycled crushed stone that can be made from 20-5mm which is ideal for a variety of uses on account of its good drainage characteristics.
Next time you see a demolition project happening or go past any construction site during a build programme, it is clear to see the volume of waste material being generated. If waste isn’t in skips, piles of rubble will be stacked high. The placing of concrete waste material in skips has been a serious concern for waste contractors for several years. I have worked within the waste sector, I have seen skip lorries tipped backwards with the cab of the vehicle up in the air, because of the sheer overloading of waste skips with building site waste.
Every year, the uk produces around 330 million tonnes of waste and approximately 90 million tonnes of this is coming from building and demolition wastes. This number has stayed reasonably steady since 2001. Around two thirds of this waste is generally recycled or reused in land reclamation or agricultural development projects. Ever since the later part of the 1990s there’s been a gradual increase in the volumes of construction waste materials being recycled and this has been helped by advances in technology that have led to improved crushing solutions to make more common use of varying grades of recycled aggregates. There is a genuine focus upon the United Kingdom construction community to encourage greater recycling of waste material on site.
In recent years, the construction industry as a whole has worked hard to persuade construction site supervisors to put a larger focus upon recycling on site. This has triggered an increase in the recycling of all inert materials from site.
Before the introduction of the landfill duty just about all construction site waste material including bricks and concrete would be bulked up and transported to a landfill site for disposal. No deliberation was given to recycling. There are now stringent regulations across the sector, in conjunction with an increase in environmental focus, and also the commercial rewards in making sure that this type of waste is now recycled. Addititionally there is increased recognition of the large choice of potential opportunities to re-use recycled aggregates in the construction process on future construction projects or in environments such as landscaping or home and garden DIY. Following the demolition process, together the waste concrete, bricks, masonry etc will 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 grade and resalable product, it must be totally free from other debris 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 typically be achieved in one of two ways. Some demolition companies will locate a crushing device on the demolition site, whereas some contractors will choose to transport the waste to be recycled, back to their own premises for sorting for recycling or re-use. On projects where demolition and new construction is to occur at the same location, the contractor is likely to locate a crushing unit on site to avoid incurring extra transportation costs in taking the material to a sorting and crushing facility.
Many recognized Nottingham demolition contractors extended their services to add site clearance services.
The Growing Interest in High Quality Recycled Aggregate
Before starting the crushing process, it must be determined what the end product is to be used for to make sure that the recycled aggregate is to match the necessary standards. There’s huge demand for recycled concrete aggregate to be used back in the construction process. As a product, recycled aggregate can be used for almost any type of concrete structural function, road surfacing or pipe laying project. Having passed through the crusher the chunks of aggregate can be sorted by size. Bigger pieces may be retained as a decorative product for use in garden rockery projects, or they may be passed back through the crusher to be pummeled to a reduced size. The small bits of recycled aggregate may be suited to use as a gravel on new construction projects, road laying or driveways at home. The crushing devices 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 high quality crushed aggregate is increasing. There are key standards in place which are concentrated upon improving the recycled concrete aggregate market. Through research and improvement, more widespread uses are now being identified for the use 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 sections of aggregate to very specific 6f2 recycled concrete which can be employed 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. As well as being used as a mix for highway 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 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.
One of the important criteria when you use recycled aggregate is selecting the right specification for the task. For example, when using 20-5mm coarse graded aggregate as a road base, the depth of the layer demanded must be determined to withstand 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 waterflow and drainage. Once the recycled aggregate is installed, appropriate layers of asphalt or concrete can be laid across it to form the road surface.
Recently, in the UK we appear to have more bad weather than sunshine and therefore the selected aggregate must have the capacity to withstand variances in temperature and conditions e.g. dampness for very long periods, torrential downpours, long dry spells. With its good drainage characteristics, the recycled 20-5mm product could be the perfect choice for many sand and gravel applications including, pipe bedding, driveways and footpaths, landscaping, plus for use in ready mixed and precast concrete products.
Demolition contractors look to produce recycled concrete material as part of the site clearance process, in making the site ready for redevelopment.
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 significant opportunity to boost awareness of climate change and the issues which surround it, and bring it to the Globe’s attention. With the eyes of the World watching, the Olympics present an exceptional opportunity to put across important messages about sustainability. Throughout the entire development of the Olympic project, there’s a determination to make 2012 by far the most sustainable Olympic Games ever held. This focus began when planning the design and build programmes for the facilities and venues, the transportation links and network, the hosting of the Games themselves and will conclude by leaving behind a long lasting heritage of a sustainable natural environment.
Ever since London was awarded the Games, all partners involved with the development requirements, from the construction of the Olympic Stadium, the Olympic Village and transport links to the venues have been encouraged upon ensuring the use wherever possible of sustainable resources. Throughout the entire Olympic build programme developers have worked hard to locate appropriate sustainable materials for use in the build programme. At the conclusion of the overall project we will see some clearly obvious examples of the use of sustainable products.
At the same time there will be many more that are much less visible, and furthermore, many which will be not visible at all. Some of those products which visitors to the games and its countless venues will not even think about how recycled aggregates are already employed as part of the overall construction project. But developers and specifiers of resources for use in the build programme will be secure in the knowledge that they have selected sustainable products including, the most appropriate recycled concrete aggregates as part of the project. With its identified characteristics, let us hope that somewhere in the worldwide TV coverage the 20-5mm recycled aggregate gets a reference somewhere, somehow.
Summary
How times have changed in recent years for the demolition and construction industry. Organisations have needed to change to meet challenging green specifications. As with just about any sector, new regulations and legislation determine the standards to which your business must aspire, if it is to be successful.
Businesses involved in the generation 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 offering 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. The demolition and construction industry now places sustainability at the forefront of its future development projects.
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