Introduction
Mention the word demolition to almost any person and the image that instantly comes to mind is often a vision of a structure being blown up and collapsing to the floor. Plenty of people have claimed that they would love to press the button, to trigger the explosive devices which bring a disused building to the floor. On many occasions what comes down, must go up and we are seeing many dilapidated structures being taken down to make way for future development, frequently together with a regeneration project.
For organizations who over several years have built their business surrounding the demolition of structures, the demolition sector has become considerably more reaching than simply demolishing old and unwanted buildings. After the building is demolished the massive task of site clearance will begin and in a modern world where consideration of the environmental effects are very high on a good number of peoples agenda, the material remains from demolition must be separated for recycling purposes. This will likely include such products as steel, wood, plastic, brickwork and concrete.
The majority of the materials are bulked up and transported to appropriate recycling plants for reprocessing. Products such as bricks and concrete are usually crushed and converted into a recycled concrete aggregate product available for reuse in the construction of new highways or structures. More and more though, by means of advancements in technological development, residues like concrete to be recycled must meet an extremely high specification for reuse in construction projects.
When crushed, the assorted sizes of recycled aggregate will govern the likely usage potential of the product. Large sizes might be used as decorative rockery products in landscaping whilst much finer, almost shingle like product can be utilised to provide a bedding for pipe laying or as a layer in road construction. Through an ever-increasing number of possibilities identified for the reuse of recycled aggregate, the whole demolition and construction market 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 Behind the Increased Focus on Recycling from Construction and Demolition Projects
In 1996, UK Government imposed a duty on all waste items going to landfill. The levy is paid out in addition to regular gate charges for waste being disposed in landfill and since its initial release the charge has increased annually. When first introduced, the typical level of tax for general waste materials being sent to landfill was �7 per tonne and �2 per tonne for inert materials. The levy was created to motivate commercial and industrial firms and local authorities collecting from households, to divert waste away from landfill for recycling. In April ’09, the typical rate of landfill duty grew to �40 per tonne and is timetabled to rise each year by �8 per tonne until 2013. The lower level of tax charged upon any inert materials going to landfill such as concrete and soils, has remained reasonably steady recently and is presently at �2.50 per tonne.
However, the weight of a bulk load of 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 industry, diverting waste from landfill is a top 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.
Following demolition and after passing through the crushing processrecycled 6F2 created from concrete and rubble from the demolished buildings can be used for a number of purposes.
Next time you see a demolition project happening or pass almost any construction site during a build programme, it will be very clear to see the amount of waste being produced. If waste is not in skips, heaps of rubble will probably be stacked high. The placing of rubble waste materials in skips has been a major issue for waste contractors for quite some time. Having been an employee 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 building site waste.
Each year, the uk produces close to 330 million tonnes of waste material and approximately 90 million tonnes of this is from building and demolition wastes. This number has stayed fairly constant since 2001. Around two thirds of this waste is generally recycled or reused in land reclamation or agricultural development projects. Ever since the late 1990s there has been a steady increase in the volumes of construction waste materials being recycled and this has been assisted by advances in technology that have led to improved crushing products to create more common use of different specifications of recycled aggregates.
In the past few years, the construction industry as a whole has worked hard to persuade construction site managers to place a larger focus upon recycling on site. This has led to an increase in the recycling of all inert materials from site.
Before the introduction of the landfill tax most construction site waste materials including bricks and concrete would be bulked up and taken to a landfill site for disposal. No thought was given to recycling. These day there are stringent regulations across the sector, coupled with an increase in environmental consciousness, and also the commercial benefits in ensuring that this kind of waste is recycled. There is also increased recognition of the large choice of potential business opportunities to use recycled aggregates within the construction process on future construction projects or in arenas such as landscaping or home and garden DIY. Following the demolition process, together the waste concrete, bricks, masonry etc will likely be transformed into a recycled concrete aggregate.
To recycle concrete aggregate to a high standard and resalable product, it must be entirely free of other impurities 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 normally be achieved in one of two ways. Some demolition companies will transport a crushing system on the demolition site, whereas some contractors will choose 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 location, the contractor is likely to locate a crushing machine on site to escape incurring extra transport costs in taking the materials back to a sorting and crushing facility.
Larger buildings to be demolished, will require expert asbestos removal and demolition contractors be appointed to regulate the project.
The Increasing Interest in Top Quality Recycled Aggregate
Before starting the crushing procedure, it has to be determined what the end product will be used for to make certain that the recycled aggregate is to meet the required standards. There is huge requirement for recycled aggregate to be used within the construction process. As a product, recycled 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 smaller size. The small pieces of recycled aggregate could 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 need for top quality crushed aggregate is increasing. There are key standards in position which are concentrated upon improving the recycled aggregate sector. Through research and development, more widespread uses are now being discovered 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 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 used in road construction or at home on driveways. In addition to being employed as a mix for road construction, recycled aggregate is being used as bedding for pipe laying or foundation 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 specifications required to allow its reuse in concrete production.
On the list of important criteria when using recycled aggregate is selecting the best specification for your task. For instance, when using 20-5mm coarse graded aggregate as a road foundation, the depth of the layer needed must be determined to stand up to 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 assists good waterflow and drainage. Once the recycled aggregate is laid, appropriate layers of asphalt or concrete can be laid across it to create the road surface.
Recently, in the United Kingdom we seem to have more bad weather than sunshine and therefore the chosen 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 qualities, the recycled 20-5mm product could be the appropriate choice for many sand and gravel applications including, pipe bedding, driveways and footpaths, landscaping, and also for use in ready mixed and precast concrete products. With its drainage qualities, 20-5mm recycled aggregate is a flexible product.
It is always better to employ a specialist company with knowledge of the latest building demolition legislation, such as BREEAM, to see one such company visit this website.
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 encircle it, and bring it to the World’s attention. With the eyes of the Entire world watching, the Olympic Games provide an exceptional opportunity to convey important points concerning sustainability. During the whole development of the Olympics project, there is a determination to make 2012 the most sustainable Olympics ever held. This focus began when planning the design and build programmes for the facilities and venues, the transport links and system, the hosting of the Games themselves and will end by leaving a long lasting heritage of a sustainable natural environment.
Ever since London was awarded the Games, all suppliers associated with the development requirements, from the building of the Olympic Stadium, the Olympic Village and transportation links between the venues have been focused upon guaranteeing the use wherever possible of sustainable resources. Throughout the entire Olympic build programme construction managers have worked hard to identify 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.
Equally 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 locations won’t even consider how recycled aggregates are specified as part of the overall construction project. But developers and specifiers of materials 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 qualities, let us 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 marketplace. Companies have needed to change to meet demanding green specifications. As with almost any industry, new laws and legislation dictate the benchmarks to which your business must aspire, if it is to be successful.
Firms engaged in the production of recycled 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 main 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 road construction and driveways.