Method for manufacturing asphalt comprising rubber from end-of-life tires
A method for producing asphalt comprising a heat treatment step, wherein the rubber granules deriving from an end-of-life tyre granulation process are subjected to a temperature of between 80 and 300° C., for a period of time necessary in order to obtain rubber granules with a density of between 1.0 and 1.5 g/cm 3 ; and a mixing step wherein the rubber granules from the heat treatment step are mixed with stone aggregate and bitumen in order to obtain asphalt.
1 . A method for producing asphalt comprising:
a heat treatment step, wherein first rubber granules deriving from an end-of-life tire granulation process are subjected to a temperature of between 8° and 300° C., for a period of time such that second rubber granules are obtained with a density of between 1.0 and 1.5 g/cm 3 ; and
a mixing step wherein the second rubber granules are mixed with stone aggregate and bitumen to obtain asphalt,
wherein the mixing step comprises a first mixing operation wherein the stone aggregate and the bitumen are mixed together at a temperature of between 15° and 200° C., and a second mixing operation wherein the second rubber granules are added to the mixture from the first mixing operation.
2 . The method of claim 1 , wherein during the heat treatment step the first rubber granules are subjected to a temperature of between 100 and 200° C., for a period of time such that the second rubber granules are obtained with a density of between 1.2 and 1.3 g/cm 3 .
3 . The method of claim 1 , wherein the second rubber granules constitute from 1 to 30% by volume of a quantity of inert material comprised within the asphalt.
4 . The method of claim 1 , wherein the first rubber granules have a substantially polyhedral conformation, wherein a ratio between a maximum size and a minimum size thereof is less than 2.
5 . The method of claim 1 , wherein the first rubber granules have dimensions to pass through a sieve having meshes with dimensions of between 10 mm and 1.5 mm.
6 . The method of claim 1 , wherein the first rubber granules have dimensions to pass through a sieve having meshes with dimensions of between 2.0 mm and 6.0 mm.
7 . The method of claim 1 , comprising a preliminary thermal step preceding the heat treatment step, wherein rubber granules are subjected to a temperature of between 120 and 200° C. for a period of time of between 15 and 30 h.
8 . The method of claim 1 , comprising a surface treatment step, subsequent to the heat treatment step and wherein the second rubber granules from the heat treatment step are subjected to a surface abrasion operation.
9 . The method of claim 8 , comprising a final heat treatment step subsequent to the surface treatment step and preceding the mixing step, wherein during the final heat treatment step the rubber granules deriving from the surface treatment step are subjected to a temperature of between 8° and 300° C. for a period of time to obtain rubber granules with a density of between 1.0 and 1.5 g/cm 3 .
10 . The method of claim 9 , wherein during the final heat treatment step the rubber granules deriving from the surface treatment step are subjected to a temperature of between 100 and 200° C. for a period of time to obtain rubber granules with a density of between 1.2 and 1.3 g/cm 3 .
11 . Asphalt manufactured using the method of claim 1 .
12 . Rubber granules and/or powder deriving from an end-of-life tire granulation process, which have dimensions to pass through a sieve having meshes with dimensions up to 10 mm and that are subjected during a heat treatment step to a temperature of between 8° and 300° C. for a period of time to obtain rubber granules and/or powder with a density of between 1.0 and 1.5 g/cm 3 , further subjected to a mixing step comprising a first mixing operation wherein the stone aggregate and the bitumen are mixed together at a temperature of between 150 and 200° C., and a second mixing operation wherein the second rubber granules are added to the mixture from the first mixing operation.
13 . The rubber granules and/or powder of claim 12 , further subjected to a preliminary thermal step, preceding the heat treatment step, and wherein the rubber granules and/or powder deriving from the granulation process are subjected to a temperature of between 120 and 200° C. for a period of time of between 15 and 30 h.
14 . The rubber granules and/or powder of claim 12 , further subjected to a surface treatment step, subsequent to the heat treatment step, and wherein the rubber granules and/or powder from the heat treatment step are subjected to a surface abrasion operation.
15 . The rubber granules and/or powder of claim 14 , further subjected to a final heat treatment step subsequent to the surface treatment step, wherein during the final heat treatment step the rubber granules and/or powder deriving from the surface treatment step are subjected to a temperature of between 80 and 300° C. for a period of time to obtain rubber granules and/or powder with a density of between 1.0 and 1.5 g/cm 3 .
16 . A method for producing asphalt comprising:
a heat treatment step, wherein first rubber granules deriving from an end-of-life tire granulation process are subjected to a temperature of between 8° and 300° C., for a period of time such that second rubber granules are obtained with a density of between 1.0 and 1.5 g/cm 3 ; and
a mixing step wherein the second rubber granules are mixed with stone aggregate and bitumen to obtain asphalt,
wherein the second rubber granules constitute from 1 to 30% by volume of a quantity of inert material comprised within the asphalt.