Introduction

Mention the phrase demolition to just about anyone and the image that instantly comes up is a vision of a structure being blown up and collapsing to the floor. Lots of people have claimed they would really like to press the button, to detonate the explosive devices which bring a disused property to the ground. On many occasions what comes down, must go up so we are witnessing many unsightly buildings being demolished to make way for potential future development, often during a regeneration project.

For firms that over a number of have established their business surrounding the demolition of structures, the demolition market is now considerably more reaching than just demolishing outdated buildings. After the building is demolished the massive task of site clearance will begin and in a society where consideration of the environmental effects are ever increasing on most peoples agenda, the material remains as a result of demolition should be separated for recycling applications. This will include such materials as steel, wood, plastic, brickwork and concrete.

Most of the materials tend to be bulked up and transported into the appropriate recycling plants for reprocessing. Products such as bricks and concrete are usually crushed and become a recycled concrete aggregate product ready for reuse in the construction of new roadways or structures. More and more though, by means of breakthroughs in technological development, derivatives such as rubble to be recycled must meet a high specification for reuse in construction projects.

When crushed, the varied sizes of recycled aggregate will govern the likely usage potential of the product. Large sizes might be employed as cosmetic rockery products in landscaping while much finer, almost shingle like product may be used as a bedding for pipe laying or as a layer in road construction. With an growing number of opportunities recognized for the reuse of recycled aggregate, the entire demolition and construction industry is making a significant contribution to sustainable development.

Reasons Behind the Increased Focus on Recycling from Construction and Demolition Projects

In 1996, UK Government imposed a tax on all waste materials going to landfill. The duty is paid in addition to standard gate rates for waste being disposed in landfill and since its initial release the cost has increased annually. When it was first introduced, the standard level of tax for general waste materials being sent to landfill was �7 per tonne and �2 per tonne for inert products. The tax was designed to persuade commercial and industrial organisations and local authorities collecting from properties, to divert waste away from landfill for recycling. In April 2009, the common rate of landfill tax increased to �40 per tonne and is timetabled to increase annually by �8 per tonne until 2013. The reduced level of duty incurred upon any inert materials going to landfill like concrete and soils, has remained reasonably steady in recent years and is currently at �2.50 per tonne.

Even so, 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 sector, diverting waste from landfill is a top priority.

The very first stage of many new build projects requires companies to identify and adere to the particular demolition legislation relevant to the property before construction work can begin.

Next time you see a demolition project happening or go past any construction site during a build programme, it will be clear to see the quantity of waste being produced. If waste material is not in skips, heaps of rubble will be stacked high. The placing of rubble waste material in skips has been a major concern for waste companies for many years. I have worked within the waste sector, I’ve seen skip trucks tipped backwards with the cab of the vehicle up in the air, because of the gross overloading of waste skips with construction site waste.

Each year, the united kingdom produces close to 330 million tonnes of waste materials and approximately 90 million tonnes of this is from construction and demolition wastes. This figure has remained reasonably steady 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 gradual increase in the quantities of construction waste being recycled and this has been aided by improvements in technology that have led to improved crushing products to make more common use of varying grades of recycled aggregates. There is a real focus upon the United Kingdom construction sector to encourage more recycling of waste on site.

In recent years, the construction sector in general has worked hard to motivate construction project managers to put a greater focus upon recycling on site. This has triggered a rise in the recycling of inert materials from site.

Before the introduction of the landfill tax just about all construction site waste material including bricks and concrete was bulked up and transferred to a landfill site for disposal. No consideration was given to recycling. There are now strict limitations across the sector, as well as an increase in environmental focus, and also the commercial benefits in ensuring that this type of waste is now recycled. Addititionally there is significantly greater recognition of the large choice of potential opportunities to re-use recycled aggregates within the construction process on future 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 be transformed into a recycled concrete aggregate.

To recycle concrete aggregate to a high standard and resalable product, it must be completely free of other debris such as wood, paper, card, steel and other general waste materials. The final product must also conform to the requirements of British Standard BS 8500. The task of recycling the concrete can typically be achieved in one of two ways. Some demolition companies will locate a crushing machine on the demolition site, whereas some contractors will choose to carry the waste to be recycled, to their premises for segregation for recycling or re-use. On projects where demolition and new construction is to take place at the same site, the contractor is very likely to position a crushing unit on site to avoid incurring extra transport costs in taking the materials to a sorting and crushing centre.

The specialist asbestos demolition contractors around Nottingham can be found by searching the word wide web.

The Increasing Need for Top Quality Recycled Aggregate

Before starting the crushing procedure, it has to be determined what the end product will be used for to ensure that the recycled aggregate is to match 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 just about any 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 may be retained as a decorative product to be used in garden rockery projects, or they might be passed back through the crusher to be pummeled to a smaller size. The smaller pieces of recycled aggregate may 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 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 demand for good quality crushed aggregate is increasing. There’s key standards in position which are concentrated upon improving the recycled aggregate market. By means of research and improvement, more widespread applications are now being discovered for the use of recycled aggregate. No longer is concrete, just concrete. What we are talking about now are many different grades of recycled aggregate, ranging from the large sections of aggregate to very specific 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. In addition to being used 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 used as an aggregate base in highway construction and the quality meets the specifications required to allow its reuse in concrete production. The 20-5mm recycled aggregate is a very versatile product.

One of the important considerations when you use recycled aggregate is selecting the correct specification for your task. For example, when making use of 20-5mm coarse graded aggregate as a road foundation, 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 used as a road base is that it supports good drainage. Once the recycled aggregate is installed, appropriate layers of asphalt or concrete can be laid above it to build the road surface.

In recent years, in the United Kingdom we appear to have more rain than hot sunshine and therefore the selected aggregate must be able to endure variances in temperatures 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 may be the perfect 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.

It may be necessary to employ asbestos removal contractors to safely remove asbestos from the building to be demolished.

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 concerns which surround it, and bring it to the World’s attention. With the eyes of the World observing, the Olympics give a unique chance to communicate key points concerning sustainability. Through the whole 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 planning the design and build programmes for the amenities 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 healthy environment.

Since London was granted the Games, all companies involved with the development requirements, from the design of the Olympic Arena, the Olympic Village and transport links to the venues have been encouraged upon ensuring the use wherever possible of sustainable materials. Across the entire Olympic build programme architects have worked hard to identify appropriate sustainable materials for use in the build programme. By the end of the overall project we will see some clearly obvious cases 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 numerous sites won’t even consider how recycled aggregates have been employed as part of the overall construction project. However developers and specifiers of resources 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. Imagine being asked to supply recycled aggregate which meets a very specific 20-5mm clean material specification, to help build the 2012 Olympic Village.

Summary

How times have developed recently in the demolition and construction business. Organisations have needed to adapt to meet demanding environmental standards. As with virtually any market, new laws and legislation dictate the criteria to which your business must aspire, if it is to be successful.

Companies 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 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 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. The demolition and construction industry now places sustainability at the forefront of its future development projects.