Co2-trapping bituminous compositions modified by incorporation of alkali metal hydroxide, associated methods and uses

A preparation method of a bituminous composition comprising a bitumen base representing at least 72% by mass of said bituminous composition, said method comprising the following successive steps:

• a) obtaining a modified bitumen base, comprising the incorporation of an alkali hydroxide into a bitumen base, said incorporation being followed by or accompanied by mixing, preferably under heating at a temperature in the range from 90 to 230° C., preferably in the range from 120 to 200° C., and preferentially in the range from 120 to 180° C.,
• b) trapping CO2 in the modified bitumen base at a mass content especially representing from 0.8 to 5.8% by mass, preferably from 0.8 to 4.5% by mass, preferentially from 0.8 to 3.5% by mass, and even more preferentially from 0.8 to 2.6% by mass, or from 0.8 to 1.8% by mass of the mass of the bitumen base.

A method for stabilizing the quantity of CO2 trapped within a bituminous composition, comprising incorporating the CO2 in said bituminous composition, followed by incorporating an alkali hydroxide.