This European Standard specifies "fly ash bound mixtures" for roads, airfields and other trafficked areas and specifies the requirements for their constituents, composition and laboratory performance classification. In this European Standard, fly ash refers to siliceous or calcareous fly ash complying with EN 14227-4. Where fly ash is part of cement or hydraulic road binder conforming to EN 197-1 or ENV 13282, then reference should be made to prEN 14227-1 and prEN 14227-5 respectively.