Bituminous binder and method for the production thereof

1. Method for preparing a bituminous binder comprising the following successive steps:

a) mixing 0.05 to 5 wt. % acid, 0.5 to 25 wt. % rubber crumb and 70 to 99.5 wt. % bitumen heated to a temperature of between 120 and 220° C.,

b) maintaining the mixture at a temperature of between 120 and 220° C. for a time of between 15 minutes and 10 hours while stirring, and

c) optionally degassing any air bubbles which may have occurred in the mixture, wherein the acid is a phosphoric acid or polyphosphoric acid.

2. Method according to claim 1 , wherein step a) is performed by mixing the bitumen and acid followed by the addition of rubber crumb.

3. Method according to claim 1 , wherein step a) is performed by pre-mixing the acid and rubber crumb before their addition to the bitumen.

4. Method according to claim 1 , wherein step a) is performed by mixing at least part of the bitumen heated to a temperature of between 120 and 220° C., and the rubber crumb adding the acid to the mixture of bitumen and rubber crumb and adding any remaining bitumen.

5. Bituminous binder obtained using the method according to claim 1 .

6. Bituminous binder according to claim 5 , wherein the ratio at 135° C. of the acid containing bituminous binder viscosity to the viscosity of an identical version of the bituminous binder which is acid-free lies between 10 and 70%

and wherein the difference in critical temperature between the acid-containing binder and the acid-free binder lies between 1 and 50° C.

7. A building formed from building construction materials which contain the bituminous binder of claim 5 or 6 .

8. A building construction material or road construction material which contains as a sealant the bituminous binder of claim 5 or 6 .

9. Bituminous concrete containing the binder according to claim 6 and a selected quantity of aggregate.

10. Method for preparing a bituminous concrete wherein the aggregate is added to the binder according to claim 5 or 6 under stirring at a temperature of between 120 and 220° C.

11. Method for preparing a bituminous concrete comprising the following steps:

i) Preparing a bitumen emulsion by mixing water, a bituminous binder according to claim 5 or 6 and an emulsifier at ambient temperature,

ii) incorporating aggregate into the bitumen emulsion obtained at step i), under stirring at ambient temperature,

iii) spreading the emulsion obtained at step ii) to obtain a uniform layer of the mixture obtained at step ii),

iv) breaking the bitumen emulsion.

12. A roadway construction having a surface coating formed of the bituminous concrete of claim 9 .

13. Method according to claim 1 , wherein prior to step (a), a pre-mix is formed containing between 0.02 wt. % and 91 wt. % acid and between 9 and 99.98 wt. % rubber crumb.

14. Bituminous binder containing 0.05 to 5% of acid, the acid being phosphoric or polyphosphoric acid, 0.5 to 25% of rubber crumb and 70 to 99.5% bitumen and having the following characteristics: the ratio at 135° C. of the acid-containing bituminous binder viscosity to the viscosity of an identical version of the bituminous binder which is acid-free lies between 10 to 70% and the difference in critical temperature between the acid containing binder and the acid-fee binder lies between 1 and 50° C.

15. Method according to claim 1 , wherein the mixture in step b) is maintained at a temperature of between 120 and 220° C. for a time of between 15 minutes and 3 hours.

16. A building having a roof, wherein the roof is formed from building materials which contain the bituminous binder of claim 5 or 6 .

17. A building construction material or road construction material which contains as a surface coating the bituminous binder of claim 5 or 6 .

18. A building construction material or road construction material which contains as a reflective cracking protection system the bituminous binder of claim 5 or 6 .

19. A roadway construction as a reflective cracking protection system formed of the bituminous concrete of claim 9 .

20. Method according to claim 1 , wherein rubber crumb is obtained by grinding tires, rubber mats or shoe soles.

21. Bituminous binder according to claim 14 , wherein the rubber crumb is obtained by grinding tires, rubber mats or shoe soles.