The 2012 Olympics and Recycled Concrete
Introduction
Mention the term demolition to almost any person and the image that instantly comes up is usually a vision of a building being blown up and collapsing to the ground. Lots of people have claimed that they would really like to push the button, to detonate the explosive systems which bring a disused building to the ground. In many cases what comes down, must go up so we are witnessing many dilapidated properties being razed to help with making way for future development, generally during a regeneration project.
For firms that over a number of have built their business around the demolition of buildings, the demolition sector is now far more reaching than just demolishing old buildings. As soon as the building is demolished the tremendous task of site clearance will begin and in a community where consideration of the environmental impacts are high on most peoples agenda, the material residues coming from demolition need to be sorted for recycling reasons. This will likely include such materials as steel, wood, plastic, brickwork and concrete.
Almost all of the materials tend to be bulked up and transported to appropriate recycling plants for reprocessing. Resources such as bricks and concrete are usually crushed and converted into a recycled concrete aggregate product ready for reuse in the making of new highways or structures. Increasingly though, by means of advancements in technological development, derivatives like rubble to be recycled have to meet a very high specification for reuse in construction projects.
When crushed, the various sizes of recycled aggregate will govern the likely usage potential of the product. Large sizes could possibly be used as decorative rockery products in gardening whilst much finer, shingle like product can be used to provide a bedding for pipe laying or as a layer in road construction. With an ever-increasing variety of possibilities identified for the reuse of recycled aggregate, the whole demolition and construction market is generating 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 For the Increased Concentration on Recycling from Construction and Demolition Projects
In 1996, UK Government added a tax on all wastes going to landfill. The tax is paid out on top of regular gate charges for waste materials being disposed in landfill and since its launch the charge has increased on an annual basis. When first introduced, the standard rate of duty for general wastes going to landfill was �7 per tonne and �2 per tonne for inert products. The levy is designed to encourage commercial and industrial companies and local authorities collecting from households, to divert waste away from landfill for recycling. In April ’09, the standard level of landfill tax increased to �40 per tonne and is also timetabled to increase every year by �8 per tonne until 2013. The reduced level of duty charged upon any inert materials going to landfill such as concrete and soils, has remained relatively stable recently and is presently at �2.50 per tonne.
Nevertheless, the weight of a bulk load of those inert products going directly to landfill will ensure that the entire cost of disposal becomes very expensive and so even in the demolition and construction industry, diverting waste from landfill is a top priority.
The materials which remain after using demolition equipment may be changed into a variety of reusable products for use in other construction projects.
The next time you see a demolition project happening or pass almost any construction site during a build programme, it’s obvious to see the volume of waste material being produced. If waste is not in skips, heaps of rubble will probably be stacked high. The placing of rubble waste in skips has been a major issue for waste companies for several years. Having worked within the waste industry, I have seen skip lorries tipped backwards with the cab of the vehicle up in the air, due to the gross overloading of waste skips with construction site waste.
Each and every year, the united kingdom produces close to 330 million tonnes of waste material and approximately 90 million tonnes of this is from building and demolition wastes. This figure has stayed reasonably steady since 2001. Close to two thirds of this waste is usually recycled or reused in land reclamation or agricultural development projects. Since the late 1990s there’s been a gradual rise in the volumes of construction waste being recycled and this has been assisted by developments in technology which have resulted in improved crushing technology to create more frequent use of various grades of recycled aggregates. There’s been a real focus upon the United Kingdom construction sector to encourage increased recycling of waste material on site.
In recent years, the construction industry in general has worked hard to encourage construction site supervisors to place a greater emphasis upon recycling on site. This has led to an increase in the recycling of inert materials from site.
Before the introduction of the landfill duty all construction site waste including bricks and concrete would be bulked up and moved to a landfill site for disposal. No regard was given to recycling. There are now stringent limitations across the sector, as well as an increase in environmental focus, and also the commercial benefits in making certain that this kind of waste is now recycled. Addititionally there is increased recognition of the large choice of potential business opportunities to re-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 be transformed into a recycled concrete aggregate.
To recycle concrete aggregate to a high standard and resalable product, it needs to be completely free from other impurities such as wood, paper, card, steel and other general waste materials. The final product must also conform to the requirements of British Standard BS 8500. The task of recycling the concrete can usually be achieved in one of two ways. Some demolition companies will transport a crushing device on the demolition site, whereas some contractors will opt to transport the waste to be recycled, to their own premises for sorting for recycling or re-use. On projects where demolition and new construction is to take place at the same location, the contractor is very likely to place a crushing unit on site to avoid incurring additional transport costs in taking the material back to a sorting and crushing facility.
Many established Nottingham demolition contractors have had to extend their services to add site clearance services.
The Growing Need for Top Quality Recycled Aggregate
Before commencing the crushing process, it needs to be determined what the end product will be used for to ensure that the recycled aggregate is to meet the required standards. There’s huge demand for recycled concrete aggregate to be used within the construction process. As a product, recycled concrete aggregate can be utilised for virtually any type of concrete structural function, road surfacing or pipe laying project. Having passed through the crusher the chunks of aggregate will be sorted by size. Bigger pieces can be retained as a decorative product for use in landscaping rockery projects, or they could be passed back through the crusher to be crushed to a reduced size. The smaller sized 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 top 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 purchased 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 interest in top quality crushed aggregate is increasing. There’s key standards in place that are concentrated upon improving the recycled concrete aggregate industry. Through research and improvement, more widespread uses are being discovered for the use of recycled aggregate. No more is concrete, just concrete. What we are talking about now a wide range of different grades of recycled aggregate, which range from the large sections 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 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 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 several important criteria when using recycled aggregate is selecting the best specification for your task. For instance, when making use of 20-5mm coarse graded aggregate as a highway base, the depth of the layer needed needs to be determined to withstand traffic flows. Traffic flow on a motorway will be significantly different to that of a country road. One reason aggregate produced to a 20-5mm specification is commonly employed as a road base is that it supports good drainage. Once the recycled aggregate is laid, suitable layers of asphalt or concrete can be laid above it to build the road surface.
Recently, in the UK we appear to have more rain than hot sunshine and therefore the chosen aggregate must be able to withstand variances in temperature and conditions e.g. dampness for long periods, torrential downpours, long dry spells. With its good waterflow and drainage qualities, the recycled 20-5mm product could be the perfect choice for some sand and gravel applications including, pipe bedding, driveways and footpaths, landscaping, plus for use in ready mixed and precast concrete products.
It may be necessary to employ asbestos removal contractors to safely remove asbestos from the building to be demolished.
Recycled Aggregates and the 2012 Olympic games
In its bid for the 2012 Olympic Games, London set sustainability as the focus of its bid. The bid team recognized a significant opportunity to boost awareness of climate change and the challenges that surround it, and bring it to the Globe’s attention. With the eyes of the World watching, the Olympics provide a unique chance to communicate key points about sustainability. During the entire growth and development of the Olympics project, there’s a commitment to make 2012 the most sustainable Olympics ever held. This focus originated when planning 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 legacy of a sustainable environment.
Since London was awarded the Games, all companies involved in the development requirements, from the construction of the Olympic Stadium, the Olympic Village and transportation links between the venues have been encouraged upon guaranteeing the use wherever possible of sustainable resources. Throughout the entire Olympic build programme construction managers have worked hard to discover suitable sustainable materials for use in the build programme. At the conclusion of the whole project there will be some clearly obvious cases 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 numerous locations will not even consider how recycled aggregates are specified as part of the overall construction project. However designers and specifiers of materials to be used within the build programme will be comfortable in the knowledge that they have selected sustainable products which include, the most suitable recycled concrete aggregates as part of the project. With its recognized characteristics, let’s hope that somewhere in the worldwide Television coverage the 20-5mm recycled aggregate gets a mention somewhere, somehow.
Summary
How times have changed recently for the demolition and construction industry. Businesses have had to adjust to meet demanding environmental conditions. As with virtually any industry, new laws and legislation determine the benchmarks to which your company must aspire, if it is to achieve success.
Companies involved in the manufacturing of recycled aggregate aren’t any different. These are generally 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 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 to be used in road construction and driveways.
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