The use of recycled aggregate in concrete in Hong Kong

In 2004, over 20 million tonnes of construction and demolition (C&D) wastes were generated in Hong Kong. Since the local landfills will be saturated in about 8 years, it is important to find a viable way to reuse these waste materials as to alleviate the demand on public fill capacity. In order to tackle the problem, the Hong Kong government has set up a temporary recycling facility in Hong Kong in 2002 for producing different sizes of recycled aggregate for use in various construction materials. This paper summarizes the details of the construction of the Hong Kong Wetland Park which consumed approximately 14,300 m3of concrete prepared with recycled aggregate. However, as of today, the recycled aggregate being reused is stringently restricted to recycled concrete aggregate (RCA). The use of other wastes such as brick and ceramic tile aggregate is prohibited momentarily even the combination of bricks and ceramic tiles constitutes a large portion of the C&D wastes. In order to facilitate the wider use of the inert portion of the C&D wastes, a preliminary study was conducted to investigate the possibility of using crushed brick and tile aggregate derived from construction and demolition waste stream as a replacement of fine aggregate in concrete. The effects of the use of fine crushed brick and tile aggregate as a 20 wt.% replacement of natural sand on the fresh and mechanical properties are presented.