Age Hardening 1 : A decrease in the penetration and/or increase in viscosity of a bituminous binder caused by loss of volatiles and oxidation of the binder resulting from exposure to weather over a period of time
Peter Milne and Kieran Sharp, ARRB Group, and Bob Ungers, consultant, Austroads Glossary of Terms (4th Ed.), Austroads Ltd., Sydney, NSW, Australia 2010. http://www.bicyclensw.org.au/files/u1/Austroads_Gl ossary_of_Terms_4th_edition.pdf (Road Trfc and Transp Sfty - Brit) {529}