Introduction
Mention the phrase demolition to just about anyone and the picture that instantly comes to mind is a vision of a building being blown up and collapsing to the floor. Plenty of people have said that they would love to press the button, to trigger the explosive units which bring a disused property to the floor. On most occasions what comes down, must go up and now we are seeing many empty properties being razed to help with making way for future development, normally together with a regeneration project.
For companies who over a number of have created their business within the demolition of buildings, the demolition market has become considerably more reaching than simply demolishing outdated buildings. As soon as the property is demolished the tremendous task of site clearance will begin and in a society where consideration of the environmental effects are very high on many peoples agenda, the material residues from demolition have to be separated for recycling applications. This can include such materials as steel, wood, plastic, brickwork and concrete.
Almost all of the materials are bulked up and transferred to the appropriate recycling plants for reprocessing. Resources such as bricks and concrete are usually crushed and become a recycled concrete aggregate product ready for reuse in the construction of new highways or buildings. Ever more though, by means of advancements in technological development, residues including concrete to be recycled must meet a very high standard for reuse in construction projects.
When crushed, the different sizes of recycled aggregate will govern the likely usage potential of the product. Large sizes could be used as ornamental rockery products in gardening whilst much finer, shingle like product can be used as a bedding for pipe laying or for a layer in highway construction. Through an ever-increasing number of options recognized for the reuse of recycled aggregate, the whole demolition and construction industry is building 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 added a tax on all waste products going to landfill. The duty is paid in addition to typical gate charges for waste being disposed in landfill and since its initial release the fee has risen on an annual basis. When it was first introduced, the standard level of duty for general waste products being sent to landfill was �7 per tonne and �2 per tonne for inert materials. The levy should inspire commercial and industrial companies and local authorities collecting from properties, 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 scheduled to rise each year by �8 per tonne until 2013. The reduced rate of tax charged upon any inert materials going to landfill such as concrete and soils, has stayed relatively stable recently and is currently at �2.50 per tonne.
Nonetheless, the weight of a bulk load of those inert products going straight to landfill will guarantee that the full cost of disposal becomes very 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.
Following demolition and after passing through the crushing processrecycled 6F2 created from concrete and rubble from the demolished buildings may be used for several different purposes.
Next time you see a demolition project happening or go past any construction site during a build programme, it will be clear to see the amount of waste materials being generated. If waste material is not in skips, heaps of rubble will probably be stacked high. The placing of concrete waste in skips has been a significant concern for waste contractors for several years. Having been an employee in the waste industry, I’ve seen skip trucks tipped backwards with the cab of the vehicle up in the air, due to the sheer overloading of waste skips with construction site waste.
Each and every year, the uk generates close to 330 million tonnes of waste material and approximately 90 million tonnes of this is from construction and demolition wastes. This figure has remained reasonably constant since 2001. Close to two thirds of this waste is normally recycled or reused in land reclamation or agricultural development projects. Ever since the late 1990s there’s been a steady increase in the volumes of construction waste being recycled and this has been assisted by improvements in technology which have led to improved crushing products to make more frequent use of varying grades of recycled aggregates. There has been a real focus upon the UK construction industry to encourage more recycling of waste material on site.
In recent years, the construction sector in general has worked hard to encourage construction project managers to put a larger emphasis upon recycling on site. This has resulted in a growth in the recycling of all inert materials from site.
Before the introduction of the landfill duty just about all construction site waste including bricks and concrete would be bulked up and transferred to a landfill site for disposal. No particular attention was given to recycling. There are now strict restrictions across the sector, as well as an increase in environmental focus, and also the commercial benefits in making certain that this type of waste is recycled. Addititionally there is better recognition of the large choice of potential business opportunities to re-use recycled aggregates within 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 likely 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 must be entirely free of other debris such as wood, paper, card, steel and other general waste materials. The final product must comply with the specifications of British Standard BS 8500. The process of recycling the concrete can usually be achieved in one of two ways. Some demolition contractors will transport a crushing machine on the demolition site, whereas a lot of contractors will opt to move the waste to be recycled, back to their own premises for segregation for recycling or re-use. On projects where demolition and new construction is to occur at the same site, the contractor is very likely to position a crushing appliance on site to escape incurring added transport costs in taking the materials to a sorting and crushing facility.
One Nottingham built demolition contractor have been supplying 20-5mm recycled aggregate to the 2012 Olympic Village construction project.
The Growing Demand for Top Quality Recycled Aggregate
Before starting the crushing process, it must be determined what the end product is to be used for to make certain that the recycled aggregate is to meet the necessary standards. There’s huge requirement for recycled concrete aggregate to be used back in the construction process. As a product, recycled aggregate can be used for just about any kind of concrete structural work, 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 cosmetic product for use in garden rockery projects, or they may be passed back through the crusher to be crushed to a smaller 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 devices 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. 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 increasing. There’s key standards in place which are focused upon improving the recycled aggregate sector. By means of research and improvement, more widespread applications are being discovered for the use of recycled aggregate. No longer is concrete, just concrete. What we are talking about now a variety of distinct grades of recycled aggregate, ranging from the large chunks of aggregate to very precise 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. 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 good quality grades the 20-5mm recycled aggregate can be used as an aggregate base in highway construction and the quality meets the specifications required to allow its reuse in concrete production. The 20-5mm recycled aggregate is a very versatile product.
On the list of important considerations when using recycled aggregate is selecting the best specification for your task. For instance, when using 20-5mm coarse graded aggregate as a road base, the thickness of the layer needed will have to 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 supports good drainage. Once the recycled aggregate is installed, suitable layers of asphalt or concrete can be laid over it to build the road surface.
In recent years, in the UK we appear to have more rain than sunshine and as a consequence the selected aggregate must have the capacity to withstand variances in temperatures 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 is the ideal choice for many sand and gravel applications including, pipe bedding, driveways and footpaths, landscaping, plus for use in ready mixed and precast concrete products. With its drainage qualities, 20-5mm recycled aggregate is a handy product.
It is always better to employ a specialist company with knowledge of the latest building demolition legislation, such as BREEAM, click here to see one such company.
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 problems that encircle it, and bring it to the Globe’s attention. With the eyes of the World watching, the Olympics give a unique opportunity to get across key points with regards to sustainability. Throughout the entire growth and development of the Olympics project, there exists a responsibility to make 2012 the most sustainable Olympic Games ever held. This focus originated when preparing the design and build programmes for the amenities and venues, the transportation links and network, the hosting of the Games themselves and will conclude by leaving behind a long lasting legacy of a sustainable natural environment.
Since London was granted the Games, all companies involved in the development specifications, from the building of the Olympic Arena, the Olympic Village and transport links between the venues have been encouraged upon ensuring the use wherever possible of sustainable materials. Across the entire Olympic build programme construction managers have worked hard to identify acceptable sustainable materials for use in the build programme. At the conclusion of the overall project we will see 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. One of those products which visitors to the games and its countless venues will not even consider how recycled aggregates are already used as part of the overall construction project. But designers and specifiers of materials to be used in the build programme will be secure 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 qualities, let’s hope that somewhere in the global TV coverage the 20-5mm recycled aggregate gets a mention somewhere, somehow.
Conclusion
How times have developed in recent years for the demolition and construction marketplace. Businesses have needed to change to meet demanding green conditions. As with just about any market, new regulations and legislation determine the benchmarks to which your business must aspire, if it is to achieve success.
Companies involved in the manufacturing of recycled concrete aggregate aren’t 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 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 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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