PURPOSE: To obtain a certain strength for a pavement material in an early time by mixing water-crushed slag, fly ash, and a converter slag, having a suitable particle size, and a fine powder slag at an optimum ratio.

CONSTITUTION: Since the application and the finishing quality of a road base material are largely affected by the combination of particle sizes, a suitable particle combination should be taken for the road base as a whole. That is, as a road base pavement material, there is used a material which is composed of 25 to 55vol.% of blast furnace annealed slag having a particle size of 25 to 5mm, 5 to 30vol.% of water-crushed slag having a particle size of less than 5mm, 20 to 45vol.% of converter slag having a particle size of less than 15mm, 2 to 8vol.% of a fine powder of slag in a range of 3,000 to 5,000cm2/g and 2 to 8vol.% of flyash in a range 25,000 to 5000cm2. Further, as an outer layer pavement material, there is used a material which is composed of 25 to 45vol.% of water crushed slag having a particle size of less than 5mm. 30 to 60vol.% of converter slag having a particle size of less than 15mm, 5 to 15vol.% of a fine powder in a range 3,000 to 5,000cm2/g and 5 to 15vol.% of flyash in a range of 2,500 to 5,000cm2/g. Thereby it is possible to obtain a pavement material which can promote the manifestation of a certain strength.