Introduction
Mention the word demolition to almost anyone and the picture that immediately comes to mind is usually a vision of a structure being blown up and collapsing to the floor. Plenty of people have claimed they would love to press the button, to detonate the explosive devices which will bring a disused property to the floor. Most of the time what comes down, must go up and now we are witnessing many old properties being razed to make way for future development, often as part of a regeneration project.
For companies who over many years have built their business around the demolition of properties, the demolition market has become considerably more reaching than just demolishing outdated buildings. When the building is demolished the massive task of site clearance will begin and in a modern world where consideration of the environmental impacts are very high on many peoples agenda, the material remains coming from demolition need to be separated for recycling reasons. This will likely include such resources as steel, wood, plastic, brickwork and concrete.
A lot of the materials are bulked up and shipped into the appropriate recycling plants for reprocessing. Resources such as bricks and concrete can be crushed and turned into a recycled concrete aggregate product available for reuse in the making of new roads or structures. More and more though, through advances in technological development, residues including concrete to be recycled have to meet a very high specification for reuse in construction projects.
When crushed, the assorted sizes of recycled aggregate will govern the likely usage potential of the product. Larger sizes could be used as cosmetic 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 street construction. With an growing variety of opportunities recognized for the reuse of recycled aggregate, the whole demolition and construction industry is generating 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 For the Increased Concentration on Recycling from Construction and Demolition Projects
In 1996, UK Government added a duty on all wastes going to landfill. The tax is paid out in addition to regular gate rates for waste being disposed in landfill and since its initial release the cost has increased annually. When it was first introduced, the common rate of tax for general waste materials being sent to landfill was �7 per tonne and �2 per tonne for inert substances. The levy was designed to encourage commercial and industrial organisations and local authorities collecting from properties, to divert waste away from landfill for recycling. In April 2009, the standard rate of landfill tax rose to �40 per tonne and is also timetabled to rise annually by �8 per tonne until 2013. The reduced rate of tax incurred upon any inert materials going to landfill like concrete and soils, has stayed relatively stable in recent years and is presently at �2.50 per tonne.
However, the weight factor alone of a bulk load of these inert products going directly to landfill will guarantee that the full cost of disposal becomes extremely expensive and so even in the demolition and construction arena, diverting waste from landfill is a priority.
For all your building site demolition company requirements find a reputable firm on line.
The 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 materials being produced. If waste material isn’t in skips, heaps of rubble will probably be stacked high. The placing of brick waste materials in skips has been a serious problem for waste contractors for several years. 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, due to the gross overloading of waste skips with construction site waste.
Every year, the united kingdom generates close to 330 million tonnes of waste and it is estimated that around 90 million tonnes of this is coming from building and demolition wastes. This figure has remained fairly constant since 2001. Around two thirds of this waste is usually recycled or reused in land reclamation or agricultural improvement projects. Ever since the late 1990s there has been a steady increase in the quantities of construction waste being recycled and this has been helped by advances in technology that have resulted in improved crushing technology to create more widespread use of varying grades of recycled aggregates.
In the past few years, the construction industry as a whole has worked hard to encourage construction site managers 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 levy just about all construction site waste including bricks and concrete was bulked up and transferred to a landfill site for disposal. No thought was given to recycling. There are now strict restrictions across the sector, coupled with an increase in environmental focus, and also the commercial advantages in making sure that this kind of waste is recycled. Addititionally there is increased recognition of the large choice of potential opportunities to 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 probably be transformed into a recycled concrete aggregate.
To recycle concrete aggregate to a high standard and resalable product, it must be entirely free from other debris such as wood, paper, card, steel and other general waste materials. The final product must 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 contractors will install a crushing system on the demolition site, whereas some contractors will choose to carry 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 occur at the same location, the contractor is very likely to position a crushing machine on site to avoid incurring additional transport costs in taking the materials back to a sorting and crushing facility.
There are various legal and environmental issues which midlands demolition contractors need to now adhere to when undertaking their projects.
The Growing Demand for High Quality Recycled Aggregate
Before starting the crushing process, it needs to be determined what the end product is to be used for to make certain that the recycled aggregate is to satisfy the required standards. There is huge demand for recycled aggregate to be used within the construction process. As a product, recycled concrete aggregate can be used for nearly every kind of concrete structural work, road surfacing or pipe laying project. Having passed through the crusher the pieces of aggregate can be separated by size. Bigger pieces can be retained as a cosmetic product to use in landscaping rockery projects, or they could be passed back through the crusher to be pummeled to a reduced size. The small bits 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 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.
The need for top quality crushed aggregate is ever-increasing. There are key standards in position which are concentrated upon improving the recycled aggregate sector. Through research and improvement, more widespread uses are being discovered for the employment of recycled aggregate. No more is concrete, just concrete. What we are talking about now are many distinct grades of recycled aggregate, ranging from the large sections 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 utilised in road construction or at home on driveways. As well as being used as a mix for highway construction, recycled aggregate is being used as bedding for pipe laying or foundation material prior to construction projects starting. In achieving such top quality grades the 20-5mm recycled aggregate can be used as an aggregate base in road building 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 requirements when you use recycled aggregate is selecting the correct specification for your task. By way of example, when making use of 20-5mm coarse graded aggregate as a road base, the depth of the layer demanded will have to be determined to withstand traffic flows. Traffic flow on a motorway will be significantly different to that of a country road. One good reason aggregate produced to a 20-5mm specification is used as a road base is that it assists good waterflow and 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 UK we seem to have more rain than hot sunshine and for that reason the selected aggregate must have the capacity to endure variances in temperature 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 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.
There is increasing demand for different recycled concrete grades to be used in various construction projects.
Recycled Aggregates and the 2012 Olympic games
In its bid for the 2012 Olympic Games, London set sustainability as the focal point of its bid. The bid team identified a big opportunity to raise awareness of climate change and the issues that encircle it, and bring it to the World’s notice. With the eyes of the Entire world observing, the Olympics provide a unique opportunity to get across key points about sustainability. During the entire growth and development of the Olympic project, there’s a determination to make 2012 the most sustainable Olympic Games ever held. This focus began when preparing 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 behind a long lasting legacy of a sustainable healthy environment.
Since London was granted the Games, all companies involved in the development specifications, from the design of the Olympic Arena, the Olympic Village and transport links between the venues have been focused upon ensuring the use wherever possible of sustainable resources. Across the entire Olympic build programme developers have worked hard to locate appropriate sustainable materials for use in the build programme. By the end of the overall project there will be some clearly visible examples of the use of sustainable products.
Similarly 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 many sites won’t even consider how recycled aggregates are used as part of the overall construction project. However developers and specifiers of materials to be used 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 world wide TV coverage the 20-5mm recycled aggregate gets a mention somewhere, somehow.
Conclusion
How times have changed recently in the demolition and construction marketplace. Businesses have been required to change to meet demanding green conditions. As with almost any sector, new laws and legislation determine the standards to which your company must aspire, if it is to be successful.
Companies engaged in the manufacturing 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 highway construction and driveways.