GB5: ECO-FRIENDLY ALTERNATIVE TO EME2 FOR LONG-LIFE COST-EFFECTIVE BASE COURSES BY OPTIMIZING AGGREGATES USING SBS MODIFIED BITUMENS

摘要

Aggregate packing concepts developed in the field of high-performance cement concretes,initially by Caquot (1937) then by contemporary researchers since the 1970's, weretransposed to the field of asphalt concretes. These concepts, associated with the use of thegyratory compactor on aggregates only, enabled the development of a new laboratory designprocedure of dense high-modulus asphalt concretes. These mixes are characterized by greatcoarse aggregate interlock and no need for low penetration grade bitumens to obtain theEME2 specifications requirements, in particular the 14,000MPa stiffness modulus value at15°C.Besides, the use of only 3.9% of SBS modified bitumen combined with such an optimizedaggregate packing leads to the design of the so-called GB5? material, showing excellentcompactability, very high stiffness modulus and above all high fatigue resistance in a singleformulation, allowing for reduced pavement thickness and greater longevity.Laboratory assessment of such materials consisted in the evaluation of compactability,moisture resistance, rutting resistance at 60°C, complex stiffness modulus at 15°C andfatigue resistance at 10°C. Apart from these results, the paper also addresses the successfulapplication of this new material on different job sites, located mainly in France.The paper illustrates that the proposed innovative material may be potentially consideredfrom now on as a relevant solution for sustainable long life pavements that do not deterioratestructurally, needing only timely surface maintenance.