Guthrie and Mallett split construction and demolition waste into three categories as follows: materials which are (1) potentially valuable in construction and easily reused/recycled, including concrete, stone masonry, bricks, tiles/pipes, asphalt and soil (2) not capable of being directly recycled but may be recycled elsewhere, including timber, glass, paper, plastic, oils and metal and (3) not easily recycled or which present particular disposal issues, including chemicals (i.e. For example, ‘there will be very little waste concrete and timber forms for disposal if pre-cast concrete elements are adopted’. However, the types and composition of onsite wastes are highly variable, depending on the construction techniques used. This has been supported by the findings of comprehensive research conducted across the United States, the United Kingdom, China, Brazil, Korea and Hong Kong, which compared the types and volumes of construction waste in these countries. In terms of weight, brick masonry and concrete present by far the largest potential for recycling in the building sector. Pinto and Agopyan went further to report that, in Brazil, the construction project waste rate is 20 to 30% of the weight of the total site building materials. In addition, Bossink and Brouwers revealed that in the Netherlands, each building material generates between 1 to 10% waste of the amount purchased resulting in an overall average of 9% of purchased materials becoming waste. Equally, 38% of solid waste in Hong Kong comes from the construction industry, and in 2006, about 40% of the available landfill capacity was used to manage construction waste. However, Fishbein estimated this amount to be as much as 30% of the total weight of building materials delivered to a building site. reported that at least 10% of all materials delivered to UK construction sites are wasted due to damage, loss and over-ordering. In the United Kingdom, the disposal of construction waste accounts for more than 50% of overall landfill volumes. At present, 75% of construction and demolition waste in the EU is being landfilled, although over 80% recycling rates have been exceptionally achieved in countries such as Germany and the Netherlands. In the EU, more than 450 million tonnes of construction and demolition waste is generated every year, which makes it the largest waste stream in quantitative terms, with the exception of mining and farm wastes. related the production of construction waste to the designed facilities’ floor areas by stating that most buildings in the United States generate between 20 to 30 kg m 2.
In the United States, around 170 million tonnes of construction and demolition waste was generated during 2003, of which 48% was estimated to be recovered. It is difficult to give exact figures of construction waste produced on a typical construction site, but it is estimated that it is as much as 30% of the total weight of building materials delivered to a building site. The main cause is poor ventilation of the timber.Mohamed Osmani, in Waste, 2011 3 Construction Waste Composition and Quantification This is manifested by the presence of external yellow spots on the ends of the timber and is often accompanied by yellowish dust especially where the pieces of timber are in contact. However, as a naturally occurring material, wood has naturally occurring enemies which come in the form of fungus (mould), worms and beetles which need to be inspected carefully.Ĭommon Rot noticed by constellation marine surveyors during detailed Yacht/Boat condition inspection and surveys. Timber that has been well seasoned and that is kept in a uniform state of moisture (neither too wet nor too dry) when properly ventilated will remain stable and with no significant degradation for many hundreds of years. some examples of materials used for yachts noted in their several years of experience by constellation marine inspectors are as under:. However, in practice all materials are subject to degradation over time from a variety of different sources. All of the above has been based on the supposition that the materials remain and function in accordance with their normal properties. There are different types of materials used in structures and how structures are put together to resist the forces. Breakdown Inspection of Material during Yacht repair Inspection.