Tam Vivian W Y, Tam C M
Griffith School of Engineering, Griffith University, Gold Coast, Queensland, Australia.
Waste Manag Res. 2009 Feb;27(1):52-8. doi: 10.1177/0734242X07079875.
Construction and demolition (C&D) waste has consumed a large portion of the landfill areas in Hong Kong. Among them, concrete occupies more than 70% of the total C&D waste by volume. Thus it is necessary to recycle concrete waste to preserve landfill areas. Various governmental departments of the Hong Kong Special Administrative Region (HKSAR) are encouraging the use of recycled aggregate (RA) in the Hong Kong construction industry by issuing various guidelines and specifications. Owing to uncertainty in their properties, however, practitioners are sceptical in using it as a substitute. In this study, an attempt has been made to look at relations among six main parameters that describe the behaviour of RA: (1) particle size distribution; (2) particle density; (3) porosity and absorption; (4) particle shape; (5) strength and toughness; and (6) chloride and sulphate contents. RA samples were obtained from nine demolition sites with service lives ranging from 10 to 40 years and another set of samples was collected from the Tuen Mun Area 38 recycling plant. The behaviour of these samples was compared with that of normal aggregate samples. This study revealed that there is a strong correlation among various parameters, and by measuring three of them: either 'particle density' or 'porosity and absorption' or 'particle shape', and 'strength and toughness', and 'chloride and sulphate contents', it is possible to assess the behaviour of RA. This can significantly help by reducing RA testing time and cost before using it as recycled aggregate concrete.
建筑及拆卸（C&D）废物占用了香港很大一部分 landfill 区域。其中，混凝土按体积计算占C&D废物总量的70%以上。因此，有必要回收混凝土废物以保护 landfill 区域。香港特别行政区（HKSAR）的各个政府部门通过发布各种指南和规范，鼓励香港建筑行业使用再生骨料（RA）。然而，由于其性能的不确定性，从业者对将其用作替代品持怀疑态度。在本研究中，试图研究描述RA性能的六个主要参数之间的关系：（1）粒度分布；（2）颗粒密度；（3）孔隙率和吸水率；（4）颗粒形状；（5）强度和韧性；（6）氯化物和硫酸盐含量。RA样本取自九个使用寿命从10年到40年不等的拆除场地，另一组样本则从屯门第38区回收厂收集。将这些样本的性能与普通骨料样本的性能进行了比较。本研究表明，各参数之间存在很强的相关性，通过测量其中三个参数：“颗粒密度”或“孔隙率和吸水率”或“颗粒形状”，以及“强度和韧性”，和“氯化物和硫酸盐含量”，就有可能评估RA的性能。这可以通过减少在将RA用作再生骨料混凝土之前的测试时间和成本，提供显著帮助。
