The 2012 Olympics and Recycled Concrete
Introduction
Mention the term demolition to just about anyone and the scene that immediately comes to mind is a vision of a building being blown up and collapsing to the ground. Many people have stated that they would love to push the button, to detonate the explosive systems which bring a disused structure to the ground. On many occasions the thing that comes down, must go up so we are seeing many unsightly buildings being taken down to make way for potential future development, generally during a regeneration project.
For firms that over a number of have developed their business surrounding the demolition of buildings, the demolition arena is now considerably more reaching than just blowing up old buildings. As soon as the structure is demolished the tremendous task of site clearance begins and in a community where consideration of the environmental effects are ever increasing on most peoples agenda, the material remains provided by demolition should be sorted for recycling applications. This can include such materials as steel, wood, plastic, brickwork and concrete.
A lot of the materials are bulked up and transported to the appropriate recycling plants for reprocessing. Products such as bricks and concrete are usually crushed and turned into a recycled concrete aggregate substance available for reuse in the making of new highways or structures. Increasingly though, by means of advancements in technological development, derivatives such as concrete to be recycled have to meet a very high specification for reuse in construction projects.
When crushed, the varied grades of recycled aggregate will determine the future usage potential of the product. Larger sizes might be employed as ornamental rockery products in gardening whilst much finer, shingle like product may be used to provide a bedding for pipe laying or as a layer in street construction. Through an increasing amount of options recognized for the reuse of recycled aggregate, the whole demolition and construction industry is building a substantial contribution to sustainable development.
Reasons For the Increased Concentration on Recycling from Construction and Demolition Projects
In 1996, UK Government imposed a tax on all waste items going to landfill. The levy is paid out in addition to normal gate charges for waste being disposed in landfill and since its introduction the fee has risen annually. When it was first introduced, the typical level of tax for general wastes being sent to landfill was �7 per tonne and �2 per tonne for inert substances. The duty is designed to inspire commercial and industrial organisations and local authorities collecting from households, to divert waste away from landfill for recycling. In April ’09, the typical rate of landfill tax increased to �40 per tonne and it is timetabled to increase every 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 comparatively stable recently and is presently at �2.50 per tonne.
However, the weight factor alone of a bulk load of inert products going straight to landfill will ensure that the full cost of disposal becomes extremely expensive and so even in the demolition and construction arena, 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.
Having completed the specific step, demolition companies often bring crushing machinery on site to crush the brickwork and concrete remains.
Next time you see a demolition project in progress or go past any construction site during a build programme, it is obvious to see the quantity of waste being produced. If waste is not in skips, piles of rubble will probably be stacked high. The placing of concrete waste in skips has been a significant problem for waste companies for several years. Having worked in 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 construction site waste.
Every year, the united kingdom generates close to 330 million tonnes of waste material and it is estimated that around 90 million tonnes of this is from building and demolition wastes. This number has stayed relatively constant since 2001. About two thirds of this waste is generally recycled or reused in land reclamation or agricultural improvement projects. Ever since the later part of the 1990s there’s been a steady rise in the quantities of construction waste being recycled and this has been assisted by developments in technology which have led to improved crushing technology to create more widespread use of various grades of recycled aggregates.
In the past few years, the construction sector as a whole has worked hard to persuade construction project supervisors to place a larger focus upon recycling on site. This has triggered an increase in the recycling of inert materials from site.
Before the introduction of the landfill tax all construction site waste material including bricks and concrete was bulked up and taken to a landfill site for disposal. No deliberation was given to recycling. There are now strict regulations across the sector, in conjunction with an increase in environmental focus, as well as the commercial rewards in making sure that this sort of waste is recycled. There is also significantly greater recognition of the vast array of opportunities to re-use recycled aggregates within the construction process on alternative construction projects or in areas 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 has to be entirely free of other contaminants such as wood, paper, card, steel and other general waste materials. The end product must comply with the specifications of British Standard BS 8500. The task of recycling the concrete can usually be achieved in one of two ways. Some demolition contractors will transport a crushing unit 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 likely to locate a crushing unit on site to escape incurring additional transportation costs in taking the material back to a sorting and crushing facility.
The crushing machinery UK demolition contractors utilize will convert brick and concrete residues into recycled aggregate for future use.
The Increasing Interest in Top Quality Recycled Aggregate
Before starting the crushing procedure, it must be determined what the end product is to be used for to make sure that the recycled aggregate is to match the required standards. There is huge demand for recycled concrete aggregate to be used back in the construction process. As a product, recycled concrete aggregate can be used for virtually any form of concrete structural work, road surfacing or pipe laying project. Having passed through the crusher the chunks of aggregate can be separated by size. Bigger pieces can be retained as a cosmetic product to be used in landscaping rockery projects, or they could be passed back through the crusher to be pummeled to a reduced size. The smaller sized bits of recycled aggregate could be suitable for use as a gravel on new construction projects, road laying or driveways at home. The crushing machines 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 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 need for top quality crushed aggregate is ever-increasing. There are key standards in place that are targeted upon improving the recycled aggregate industry. By means of research and development, more widespread uses are now being identified for the employment of recycled aggregate. No more is concrete, just concrete. What we are talking about now a variety of distinct grades of recycled aggregate, which range 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 employed as a mix for road construction, recycled aggregate is being used as bedding for pipe laying or base material prior to construction projects starting. 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.
On the list of important considerations when using recycled aggregate is choosing the best specification for your task. For instance, when using 20-5mm coarse graded aggregate for a highway foundation, the depth of the layer demanded 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 used as a road base is that it aids good drainage. Once the recycled aggregate is installed, suitable layers of asphalt or concrete can be laid above it to form the road surface.
In recent years, in the United Kingdom we seem to have more rain than hot sunshine and as a consequence the chosen 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 characteristics, the recycled 20-5mm product could be the perfect choice for a lot of 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 company with specialist knowledge of building demolition procedures and site clearance experience.
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 identified a significant opportunity to boost awareness of climate change and the issues that encircle it, and bring it to the World’s notice. With the eyes of the World observing, the Olympics present an exceptional chance to get across key points with regards to sustainability. Throughout the entire growth and development of the Olympics project, there is a responsibility to make 2012 by far the most sustainable Olympic Games ever held. This focus began when setting up the development and build programmes for the amenities and venues, the transport links and network, the hosting of the Games themselves and will end by leaving a long lasting legacy of a sustainable natural environment.
Since London was awarded the Games, all suppliers involved with the development requirements, from the construction of the Olympic Arena, the Olympic Village and transport links between the venues have been encouraged upon guaranteeing the use wherever possible of sustainable resources. Across the entire Olympic build programme developers have worked hard to locate practical sustainable materials for use in the build programme. By the end of the whole project we will see some clearly obvious cases 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 venues will not even consider how recycled aggregates are used as part of the overall construction project. But developers 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 TV coverage the 20-5mm recycled aggregate gets a reference somewhere, somehow.
Summary
How times have developed recently for the demolition and construction business. Companies have needed to adapt to meet tough green standards. As with virtually any industry, new regulations and legislation determine the benchmarks to which your company must aspire, if it is to achieve success.
Companies involved in the production of recycled aggregate aren’t any 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 highway construction and driveways.
This entry was posted on Monday, January 31st, 2011 at 4:43 am and is filed under General. You can follow any responses to this entry through the RSS 2.0 feed. Both comments and pings are currently closed.