بازیافت و مدیریت ضایعات شیشه در تولیدات بتنی

ABSTRACT Management and recycling of waste glass in concrete products: Current situations in Hong Kong

Waste reduction and recycling are very important elements in a waste management framework because they help to conserve natural resources and reduce demand for valuable landfill space. Discarded beverage glass bottles, being one of the significant municipal waste types has been a major concern in Hong Kong as only few recycling channels can be identified. Government data has shown that about 373 tonnes of glass waste is generated daily in Hong Kong, but, the recovery rate is less than 3.3% (EPD, 2010).

Today, discarded waste glass already is a burden on the waste disposal facilities in many parts of the world. In most countries, generally glass bottles are just used once or a few times and then discarded. Unlike other forms of waste like paper or organic constitutes, waste glass bottles will remain stable after disposed of at landfills and it also constitutes a high proportion of the residues should incineration is used for waste treatment. Ideally, the waste glass should either be reused or remanufactured to produce new glass containers. However, due to the lack of a glass manufacturing industry, opportunities for reusing and remanufacturing of waste glass in Hong Kong are rather limited. Also, during the waste collection processes, some of the collected waste glass becomes contaminated, colour-mixed or even broken, which render them unsuitable for reusing and remanufacturing of new glass products. There are keen interests to develop alternative markets to utilize recycled glass. Since all commercial glasses are based on silica, which consists of over 70% SiO2, it is believed that waste glass can be crushed and sorted into desired particle sizes as aggregates or as a pozzolanic material for applications in the construction industry.

In this paper, the present management and recycling situation of waste glass in Hong Kong is reviewed. The research and development undertaken by The Hong Kong Polytechnic University (PolyU) on the use of recycled glass as an aggregate replacement in different concrete products is presented. Moreover, the existing and potential applications of the developed glass-concrete products in the construction industry are discussed.