[en] Paper presents and discusses data obtained in a testing program on the replacement of limestone powder in asphalt concretes by fly ashes. This would combine economic, environmental and technical benefits. The finest fly ash of Vietnamese origin scored best. This is proposed due to the gap-graded design of the particulate mixture of coarse crushed rock fractions, fine fluvial sand and the mineral admixture. The test program encompassed Marshall tests, creep tests and splitting tensile tests.