We Claim:
1. A bitumen/polymer composition comprising:
 bitumen,
5  at least one elastomer, and
 at least one olefinic polymer adjuvant functionalized by at least one epoxy group,
characterized in that the elastomer is a heat-crosslinkable block copolymer of formula
S-B-S, in which each S independently represents a block based on monovinylaromatic
hydrocarbon monomers and B represents a block based on butadiene monomers, in
10 which the S blocks represent, together, at least 15 mol% of the total number of moles
of the heat-crosslinkable block copolymer, said heat-crosslinkable block copolymer has
a weight-average molecular weight ranging from 40 000 to 500 000 g.mol-1 and exhibits
a content of vinyl groups of greater than or equal to 20 mol%, with respect to the total
number of moles of the heat-crosslinkable block copolymer.
15
2. The composition as claimed in claim 1, in which each S represents a polystyrene
block.
3. The composition as claimed in either one of the preceding claims, in which the
20 heat-crosslinkable block copolymer exhibits a content of vinyl groups of greater than or
equal to 25 mol%, with respect to the total number of moles of the heat-crosslinkable
block copolymer, preferably of greater than or equal to 28 mol%.
4. The composition as claimed in any one of the preceding claims, in which the S
25 blocks of the heat-crosslinkable block copolymer represent, together, from 15 mol% to
50 mol% of the total number of moles of the heat-crosslinkable block copolymer,
preferably from 16 mol% to 30 mol%, more preferentially from 16 mol% to 25 mol% and
more preferentially still from 16 mol% to 20 mol%.
30 5. The composition as claimed in any one of the preceding claims, which comprises
from 0.5% to 20% by weight of elastomer, with respect to the total weight of the
composition, preferably from 0.5% to 15% by weight.
6. The composition as claimed in any one of the preceding claims, which comprises
35 from 0.05% to 2.5% by weight of olefinic polymer adjuvant functionalized by at least
one epoxy group, with respect to the total weight of the composition, preferably from
0.15% to 2% by weight.
7. The composition as claimed in any one of the preceding claims, in which the
olefinic polymer adjuvant functionalized by at least one epoxy group is chosen from the
group consisting of:
(a) copolymers, preferably random, of ethylene and of a monomer chosen from glycidyl
5 acrylate and glycidyl methacrylate, comprising from 50% to 99.7% by weight of
ethylene;
(b) terpolymers, preferably random, of ethylene, of a monomer A chosen from vinyl
acetate and C1 to C6 alkyl acrylates or methacrylates and of a monomer B chosen from
glycidyl acrylate and glycidyl methacrylate, comprising from 0.5% to 40% by weight of
10 motifs resulting from the monomer A and from 0.5% to 15% by weight of motifs resulting
from the monomer B, the remainder being formed of motifs resulting from ethylene; and
(c) mixtures of at least two compounds (a) and (b).
8. The composition as claimed in claim 7, in which the olefinic polymer adjuvant
15 functionalized by at least one epoxy group is chosen from random terpolymers of
ethylene, of a monomer A chosen from C1 to C3 alkyl acrylates or methacrylates and of
a monomer B chosen from glycidyl acrylate and glycidyl methacrylate, comprising from
0.5% to 40% by weight of motifs resulting from the monomer A and from 0.5% to 15%
by weight of motifs resulting from the monomer B, the remainder being formed of motifs
20 resulting from ethylene.
9. The composition as claimed in claim 8, in which the olefinic polymer adjuvant
functionalized by at least one epoxy group is chosen from random terpolymers of
ethylene, of a monomer A chosen from ethyl acrylate or ethyl methacrylate and of a
25 monomer B chosen from glycidyl acrylate and glycidyl methacrylate, comprising from
0.5% to 40% by weight of motifs resulting from the monomer A and from 0.5% to 15%
by weight of motifs resulting from the monomer B, the remainder being formed of motifs
resulting from ethylene.
30 10. A method for the preparation of a heat-crosslinked bitumen/polymer composition
from a composition as claimed in any one of claims 1 to 9, characterized in that the
following are brought into contact, the operation being carried out at temperatures
ranging from 100°C to 200°C:
- bitumen,
35 - from 0.5% to 20% by weight of at least one elastomer,
- from 0.05% to 2.5% by weight of at least one olefinic polymer adjuvant functionalized
by at least one epoxy group,
- optionally additives.
11. The method as claimed in claim 10, in which the operation is carried out at a
temperature ranging from 160°C to 195°C, preferably ranging from 160°C to 180°C.
12. A heat-crosslinked bitumen/polymer composition obtained by the method as
5 claimed in either one of claims 11 and 12.
13. An asphalt, characterized in that it comprises at least one bitumen/polymer
composition as claimed in any one of claims 1 to 9 or at least one heat-crosslinked
bitumen/polymer composition as claimed in claim 12, and inorganic and/or synthetic
10 fillers.
14. A bituminous mix, characterized in that it comprises at least one
bitumen/polymer composition as claimed in any one of claims 1 to 9 or at least one
heat-crosslinked bitumen/polymer composition as claimed in claim 12, aggregates and
15 optionally inorganic and/or synthetic fillers.
15. The use of at least one bitumen/polymer composition as claimed in any one of
claims 1 to 9 or of at least one heat-crosslinked bitumen/polymer composition as
claimed in claim 12 for preparing a surface coating, a hot mix, a warm mix, a cold mix,
20 a cold-poured mix or a grave emulsion, said bitumen/polymer composition being
combined with aggregates and/or recycled milled products.
16. The use of at least one bitumen/polymer composition as claimed in any one of
claims 1 to 9 or of at least one heat-crosslinked bitumen/polymer composition as
25 claimed in claim 12 for preparing a leaktight coating, a membrane or a seal coat.