Page 139 - Materials Chemistry, Second Edition

6.4 Recycling of construction and demolition waste 135
wood, etc. Different structures and building construction types generate waste of which the
components are different; the basic composition is classified, mainly by the soil, sediment,
scattered mortar, concrete, carved masonry, and reinforced concrete pile under the concrete
debris heading, piling, scrap metal, waste from bamboo timber, decoration, all kinds of pack-
aging materials, and other wastes, etc.
In recent years, China’s annual CDW emissions are about 1.55 billion tons to 2.4 billion
tons, accounting for about 30%–40% of urban waste, causing a serious ecological crisis. For
a long time, due to the lack of unified and perfect CDW management methods, and the lack
of scientific, effective, economic, and feasible disposal technology, the vast majority of CDW
without any treatment will be shipped to the suburbs for open stacking or simple landfill. In
2017, CDW generated in China was about 2.379 billion tons, among which only 119,000 tons
were recycled. Recycled aggregates are mainly processed from discarded concrete, mortar,
bricks, etc.
The average recovery rate of construction waste in China is around 5%. Based on the lit-
erature review and survey, challenges of CDW management in China were analyzed by
interviews with relevant stakeholders, including researchers, building designers, construc-
tion and demolition company staff, and CDW treatment/recycling company managers
(in total, 40 people). We explored the problems of construction waste management in China
based on the 3R principle of circular economy, and summarized some of the following
existing problems of building recycling in China (Huang et al., 2018b).

• Barriers for Reducing
Lack of design standards for reducing CDW
Low cost for CDW disposal
Inappropriate urban planning
• Barriers for Reusing
Informal collection
Lack of guidance for effective CDW collection and sorting
Lack of standards for reused CDW
• Barriers to Recycling
Ineffective government regulation
Immature recycling technology
Lack of standards for recycled CDW products

Based on these findings, suggestions to promote CDW management based on 3R principle
were proposed. Firstly, effective circular economy models in building and other related in-
dustries should be designed. In order to enforce reduction of CDW, it is necessary to reinforce
the source control. For example, building design and construction stakeholders should sign
an agreement to develop green construction programs in which they jointly manage the
CDW. Enhanced supervision and management is in urgent necessary for implementing reuse
and recycling of CDW. Approaches of this aspect include establishing a coherent “top-down”
regulatory system, carrying out process monitoring of CDW, and implementing strict pun-
ishment for illegal CDW treatment behaviors. Innovative technologies are also essential for
promoting circular economy of CDW. Other than promoting technologies of classification
and separating of CDW, contributions of joint technologies such as precast construction
and BIM should also be explored. Last but not least, government should encourage economic