The spatial approach of hot mix asphalt

<p align="LEFT">A number of factors have caused a world-wide reconsideration of hot mix asphalt design methods during the last decade, like:<span style="font-family: SymbolMT; font-size: small;"><span style="font-family: SymbolMT; font-size: small;"> <br />. </span></span><span style="font-family: TimesNewRomanPSMT; font-size: small;"><span style="font-family: TimesNewRomanPSMT; font-size: small;">Increasing structural requirements due to traffic loading and more emphasis on functional requirements<br /><span style="font-family: SymbolMT; font-size: small;"><span style="font-family: SymbolMT; font-size: small;">&middot; </span></span><span style="font-family: TimesNewRomanPSMT; font-size: small;"><span style="font-family: TimesNewRomanPSMT; font-size: small;">Extrapolation out of the empirical methods like the Marshall method is not permitted. Porous Asphalt and Stone Mastic Asphalt are well known because of their high resistance to permanent deformation, but would fail to pass the Marshall <span style="font-family: TimesNewRomanPSMT; font-size: small;"><span style="font-family: TimesNewRomanPSMT; font-size: small;">requirements of conventional hot mix asphalt mixtures at 60</span></span><span style="font-family: TimesNewRomanPSMT; font-size: xx-small;"><span style="font-family: TimesNewRomanPSMT; font-size: xx-small;">o</span></span><span style="font-family: TimesNewRomanPSMT; font-size: small;"><span style="font-family: TimesNewRomanPSMT; font-size: small;">C.<br /><span style="font-family: SymbolMT; font-size: small;"><span style="font-family: SymbolMT; font-size: small;">&middot; </span></span><span style="font-family: TimesNewRomanPSMT; font-size: small;"><span style="font-family: TimesNewRomanPSMT; font-size: small;">Functional requirements at the surface like evenness, skid resistance, noise, splash and spray are not covered at all in mix designs.<br /><span style="font-family: SymbolMT; font-size: small;"><span style="font-family: SymbolMT; font-size: small;">&middot; </span></span><span style="font-family: TimesNewRomanPSMT; font-size: small;"><span style="font-family: TimesNewRomanPSMT; font-size: small;">Developments of mixes and binders; reuse of asphalt (Reclaimed Asphalt Pavement) and use of waste materials in mixes. In this paper general considerations will be presented for improved mix designs, production control and prediction of performance properties. The relations and discrepancies between behaviour in the field, testing in the laboratory and volumetric mix design must be understood. The basis of this is the spatial approach. Examples are given of the use of the spatial approach in relation to the volumetric properties from mix design to the performance of the material in the construction.</span></span></span></span></span></span></span></span></span></span></p>