Numerous research into application of some waste materials and by-products in construction has resulted in knowledge of the behavior of such materials, its impact on the environment and the creation of guidelines and standards for their application. But in order to protect the environment and keep up with demands of sustainable development, people are turning towards renewable resources. Thus less known but potentially reusable and beneficial waste materials and byproducts are being generated. Waste materials that will be increasingly accumulated in coming years, due to European directive (Directive 2009/28/EC) on usage of renewable energy sources, are bioashes. In Croatia first power plants that incinerate biomass for energy production were developed in the last few years. Some of the largest of this newly built power plants are situated in eastern Croatia due to its good predisposition for biomass cultivation. So it is necessary to find different solutions to reuse locally generated ashes, as opposed to disposing it to landfills which is in most cases current practice.
Research on locally accumulated bioashes as alternative construction material is currently being conducted on Croatian universities, mostly by testing mechanical properties of application in concretes and different aspects of road construction. Along with testing mechanical properties, ecological impact that utilization of bioash has on environment cannot be neglected in desire to enable their wider application. This paper deals with legislative treatment and ecological acceptability of bioashes as road construction materials with emphasis on heavy metal content in wood biomass fly ashes.

bioash, alternative materials, road construction, ecological acceptability