There are an increasing number of initiatives worldwide that are using waste plastic as components of building and construction materials. Incorporating plastics into roads is becoming more commonplace, with examples and various techniques used in Indonesia, India, Australia, the UK and most recently in New Plymouth.
A similar type of chemical transformation has been adopted by Enviroplaz International Ltd, who have their Head Office in Wiri, to produce an aggregate substitute to make superior-grade concrete using plastic waste feedstock (all grades 1-7, unsorted and unwashed).
Plazrok™ is a lightweight composite aggregate, manufactured from mixed waste plastic, which can be used as an additive for a range of concrete applications. Its particular advantage is the ability to use unsorted plastic – most of which would otherwise be landfilled. Concrete made with Plazrok™ can be manufactured between 10 – 40% lighter than traditional stone aggregate and has similar mechanical properties, which leads to reduction in transport costs and emissions to the construction site. It also has potential advantages in terms of ability to flex.
The material can be multiply recycled and its main applications would be tilt up slabs and non-structural elements of high-rise buildings. It is currently undergoing independent tests to provide assurance of its properties.Applications of mixed plastic waste into building and roading materials need to be accompanied by robust testing of the environmental and health impacts associated with these materials in the short and long term, particularly related to the chemical additives in the plastics and possible contribution of microplastics into the environment.