Introduction
Mention the word demolition to just about anyone and the picture that immediately comes to mind is often a vision of a building being blown up and collapsing to the floor. Plenty of people have stated they would really like to push the button, to trigger the explosive systems which bring a disused property to the floor. Most of the time the thing that comes down, must go up and we are witnessing many empty properties being razed to make way for potential future development, frequently within a regeneration project.
For businesses who over several years have developed their business within the demolition of properties, the demolition sector is now much more reaching than just demolishing unwanted buildings. As soon as the property is demolished the tremendous task of site clearance starts and in a world where consideration of the environmental impacts are high on many peoples agenda, the material residues from demolition need to be separated for recycling purposes. This tends to include such resources as steel, wood, plastic, brickwork and concrete.
The vast majority of the materials tend to be bulked up and transported to appropriate recycling plants for reprocessing. Resources such as bricks and concrete can be crushed and become a recycled concrete aggregate product ready for reuse in the construction of new roads or structures. Ever more though, by means of advancements in technological development, derivatives such as concrete to be recycled must meet a very high specification for reuse in construction projects.
When crushed, the varied sizes of recycled aggregate will govern the likely usage potential of the product. Larger sizes could be utilised as decorative rockery products in gardening whilst much finer, almost shingle like product can be utilised as a bedding for pipe laying or as a layer in road construction. Through an increasing amount of possibilities identified for the reuse of recycled aggregate, the entire demolition and construction industry is generating a significant contribution to sustainable development.
Reasons For the Increased Focus on Recycling from Construction and Demolition Projects
In 1996, UK Government imposed a levy on all waste materials going to landfill. The levy is paid out in addition to regular gate rates for waste materials being disposed in landfill and since its initial release the price has risen annually. When it was first introduced, the common level of tax for general waste products going to landfill was �7 per tonne and �2 per tonne for inert products. The duty was designed to motivate 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 rose to �40 per tonne and is also 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 fairly stable in recent years and is currently at �2.50 per tonne.
Nonetheless, the weight of a bulk load of these inert materials going straight to landfill will ensure that the entire cost of disposal becomes extremely expensive and so even in the demolition and construction market, diverting waste from landfill is a 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 your demolished buildings may be used for a variety of purposes.
The next time you see a demolition project in progress or pass almost any construction site during a build programme, it will be clear to see the quantity of waste materials being produced. If waste isn’t in skips, piles of rubble will probably be stacked high. The placing of brick waste material in skips has been a serious issue for waste contractors for several years. I have worked within the waste sector, I’ve 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.
Each year, the united kingdom generates close to 330 million tonnes of waste materials and it is estimated that around 90 million tonnes of this is from building and demolition wastes. This figure has stayed reasonably constant since 2001. About 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 steady increase in the quantities of construction waste materials being recycled and this has been aided by developments in technology which have resulted in improved crushing products to make more widespread use of varying specifications of recycled aggregates.
In recent years, the construction industry in general has worked hard to motivate construction project supervisors to put a larger focus upon recycling on site. This has resulted in a rise in the recycling of all inert materials from site.
Before the introduction of the landfill tax most construction site waste including bricks and concrete was bulked up and transported to a landfill site for disposal. No particular attention was given to recycling. Nowadays there are strict restrictions across the sector, as well as an increase in environmental awareness, as well as the commercial advantages in making sure that this sort of waste is recycled. There is also greater recognition of the vast array of business opportunities to re-use recycled aggregates within the construction process on new 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 likely be transformed into a recycled concrete aggregate.
To recycle concrete aggregate to a high grade and resalable product, it has to be totally free of other debris such as wood, paper, card, steel and other general waste materials. The final product also needs to 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 companies will transport a crushing device on the demolition site, whereas some contractors will prefer to carry the waste to be recycled, to their own premises for separation 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 transport costs in taking the materials to a sorting and crushing facility. There is now very complex crushing equipment available to reduce concrete to a very fine specification.
There are numerous legal and environmental issues that the midlands demolition contractors need to now stick to when undertaking their projects.
The Increasing Interest in Top Quality Recycled Aggregate
Before commencing 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 meet the required standards. There is huge demand for recycled aggregate to be used during the construction process. As a product, recycled concrete aggregate can be used for virtually 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 to use in garden rockery projects, or they could be passed back through the crusher to be pummeled to a smaller 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 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 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 high quality crushed aggregate is ever-increasing. There’s key standards in place that are focused upon improving the recycled concrete aggregate industry. By means of research and development, more widespread uses are now being discovered for the employment of recycled aggregate. No more is concrete, just concrete. What we are talking about now a wide range of distinct grades of recycled aggregate, ranging from the large sections of aggregate to very precise 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. 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 commencing. In achieving such good quality grades the 20-5mm recycled aggregate can be utilised as an aggregate base in road building and the quality meets the standards 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 you use recycled aggregate is choosing the correct specification for the task. By way of example, when using 20-5mm coarse graded aggregate as a highway base, the depth 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 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, suitable layers of asphalt or concrete can be laid over it to form the road surface.
In recent years, in the UK we appear to have more bad weather than sunshine and for that reason the chosen aggregate must be able to endure 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 ideal choice for some 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 handy product.
In matters as complex as demolition it is advised to retain a specialist company conversant with BREEAM and other demolition legislation www.eastmidlandsdemolition.co.uk is one such company that comes highly recommended.
Recycled Aggregates and the 2012 Olympic games
In its bid for the 2012 Olympic Games, London placed sustainability as the focal point of its bid. The bid team recognized a big 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 observing, the Olympics provide a unique chance to get across important points about sustainability. During the entire growth and development of the Olympic project, there is a commitment to make 2012 by far the most sustainable Olympic Games ever held. This focus began when preparing the development and build programmes for the amenities and venues, the transport links and system, the hosting of the Games themselves and will conclude by leaving a long lasting legacy of a sustainable healthy environment.
Since London was granted the Games, all companies involved with the development specifications, from the construction of the Olympic Arena, the Olympic Village and transport links between the venues have been focused upon ensuring the use wherever possible of sustainable materials. Throughout the entire Olympic build programme developers have worked hard to identify practical sustainable materials for use in the build programme. By the end of the overall project we will see some clearly visible 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 numerous locations will not even consider how recycled aggregates are specified as part of the overall construction project. However developers and specifiers of resources for use within the build programme will be comfortable in the knowledge that they have selected sustainable products which include, the most suitable recycled aggregates as part of the project. With its recognized qualities, let’s hope that somewhere in the global TV coverage the 20-5mm recycled aggregate gets a reference somewhere, somehow.
Conclusion
How times have changed recently in the demolition and construction sector. Businesses have needed to adapt to meet tough green requirements. As with almost any market, new regulations and legislation dictate the standards to which your company must aspire, if it is to be successful.
Businesses engaged in the generation of recycled aggregate are not 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.