The 2012 Olympics and Recycled Concrete
Introduction
Mention the term demolition to just about anyone and the image that promptly comes up is usually a vision of a building being blown up and collapsing to the ground. Plenty of people have said that they would love to press the button, to trigger the explosive units that bring a disused structure to the ground. Often what comes down, must go up and we are seeing many old properties being razed to help with making way for future development, usually during a regeneration project.
For firms who over several years have created their business around the demolition of buildings, the demolition arena has become considerably more reaching than simply demolishing outdated buildings. As soon as the property is demolished the massive task of site clearance begins and in a community where consideration of the environmental effects are high on most peoples agenda, the material remains from demolition need to be separated for recycling purposes. This will include such materials as steel, wood, plastic, brickwork and concrete.
The vast majority of the materials tend to be bulked up and shipped to appropriate recycling plants for reprocessing. Materials such as bricks and concrete are generally crushed and converted into a recycled concrete aggregate product completely ready for reuse in the making of new roads or structures. Ever more though, via advances in technological development, residues including rubble to be recycled need to meet a very high specification for reuse in construction projects.
When crushed, the different sizes of recycled aggregate will govern the likely usage potential of the product. Larger sizes could be utilised as ornamental rockery products in gardening whilst much finer, almost shingle like product can be used as a bedding for pipe laying or as a layer in highway construction. Through an growing number of options recognized for the reuse of recycled aggregate, the entire demolition and construction market is generating a significant contribution to sustainable development.
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 fees for waste materials being disposed in landfill and since its introduction the fee has increased annually. When first introduced, the common rate of duty for general waste materials being sent to landfill was �7 per tonne and �2 per tonne for inert substances. The tax was designed to motivate commercial and industrial companies and local authorities collecting from properties, to divert waste away from landfill for recycling. In April 2009, the common level of landfill duty rose to �40 per tonne and it is timetabled to increase every year by �8 per tonne until 2013. The reduced rate of duty charged upon any inert materials going to landfill such as concrete and soils, has stayed reasonably steady in recent years and is currently at �2.50 per tonne.
Nevertheless, the weight of a bulk load of these inert products going direct to landfill will guarantee that the full cost of disposal becomes horrendously expensive and so even in the demolition and construction sector, diverting waste from landfill is a priority.
Having completed the initial phase, demolition companies often bring crushing machinery on site to crush the brickwork and concrete remains.
The next time you see a demolition project in progress or pass almost any construction site during a build programme, it is obvious to see the volume of waste material being created. If waste material is not in skips, piles of rubble will probably be stacked high. The placing of concrete waste materials in skips has been a major issue for waste contractors for many years. I have worked 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.
Each and every year, the uk produces 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 figure has remained relatively steady since 2001. Around two thirds of this waste is normally recycled or reused in land reclamation or agricultural development projects. Ever since the late 1990s there has been a steady rise in the volumes of construction waste being recycled and this has been helped by improvements in technology which have led to improved crushing technology to create more common use of various grades of recycled aggregates.
In the past few years, the construction sector as a whole has worked hard to motivate construction site supervisors to place a larger focus upon recycling on site. This has led to a rise in the recycling of all inert materials from site.
Prior to the introduction of the landfill levy most construction site waste including bricks and concrete would be bulked up and transferred to a landfill site for disposal. No thought was given to recycling. There are now strict limitations across the sector, as well as an increase in environmental awareness, as well as the commercial advantages in making certain that this type of waste is recycled. There is also greater recognition of the wide array of business opportunities to use recycled aggregates in the construction process on alternative construction projects or in arenas 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 has to be entirely free from other contaminants such as wood, paper, card, steel and other general waste materials. The final product must also 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 locate a crushing device on the demolition site, whereas a lot of contractors will opt to move 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 occur at the same site, the contractor is likely to position a crushing unit on site to avoid incurring added transport costs in taking the materials back to a sorting and crushing centre.
One Nottingham built demolition contractor are supplying 20-5mm recycled aggregate to the 2012 Olympic Village construction project.
The Growing Interest in High Quality Recycled Aggregate
Before commencing the crushing procedure, it must be determined what the end product is to be used for to ensure that the recycled aggregate is to satisfy the necessary standards. There’s huge demand for recycled concrete aggregate to be used during the construction process. As a product, recycled aggregate can be utilised for almost any kind of concrete structural work, road surfacing or pipe laying project. Having passed through the crusher the pieces of aggregate will be sorted by size. Bigger pieces may be retained as a cosmetic product to use in garden rockery projects, or they may be passed back through the crusher to be crushed to a reduced size. The smaller sized bits of recycled aggregate could 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 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 interest in good quality crushed aggregate is ever-increasing. There are key standards in place which are concentrated upon improving the recycled aggregate sector. By means of research and development, more widespread uses are being identified for the employment of recycled aggregate. No longer is concrete, just concrete. What we are talking about now a wide range of distinct grades of recycled aggregate, which range 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 used in road construction or at home on driveways. In addition to being employed 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 utilised as an aggregate base in road building and the quality meets the specifications necessary to allow its reuse in concrete production. The 20-5mm recycled aggregate is a very versatile product.
One of the important requirements when you use recycled aggregate is choosing the correct specification for your task. For instance, when making use of 20-5mm coarse graded aggregate as a highway base, the depth of the layer demanded must 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 drainage. Once the recycled aggregate is laid, suitable layers of asphalt or concrete can be laid above it to build the road surface.
In recent years, in the United Kingdom we seem 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 very long periods, torrential downpours, long dry spells. With its good waterflow and drainage characteristics, the recycled 20-5mm product could be the appropriate choice for some sand and gravel applications including, pipe bedding, driveways and footpaths, landscaping, plus for use in ready mixed and precast concrete products.
It is always better to employ a specialist company with knowledge of the latest building demolition legislation, one such campany can be found by clicking here.
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 big opportunity to boost awareness of climate change and the problems which surround it, and bring it to the World’s notice. With the eyes of the World observing, the Olympic Games present a unique opportunity to get across important points about sustainability. During the whole growth and development of the Olympic project, there exists a determination to make 2012 the most sustainable Olympics ever held. This focus began when preparing the design and build programmes for the facilities and venues, the transportation links and network, the hosting of the Games themselves and will conclude by leaving a long lasting legacy of a sustainable environment.
Ever since London was awarded the Games, all partners involved with the development requirements, from the design of the Olympic Stadium, the Olympic Village and transport links to the venues have been focused upon guaranteeing the use wherever possible of sustainable materials. Across the entire Olympic build programme construction managers have worked hard to discover acceptable sustainable materials for use in the build programme. By the end of the overall project we will see some clearly visible 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 countless sites will not even think about how recycled aggregates are used as part of the overall construction project. However developers and specifiers of materials to be used within the build programme will be comfortable in the knowledge that they have selected sustainable products including, the most suitable recycled concrete aggregates as part of the project. With its identified qualities, let us hope that somewhere in the world wide Television coverage the 20-5mm recycled aggregate gets a reference somewhere, somehow.
Conclusion
How times have developed recently for the demolition and construction marketplace. Companies have been required to change to meet demanding green conditions. As with almost any industry, new laws and legislation determine the benchmarks to which your business must aspire, if it is to achieve success.
Businesses engaged in the manufacturing of recycled aggregate aren’t any different. These are 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 important 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.
