CONGLOMERATE FOR MAKING ROAD PAVEMENTS,COMPOUND FOR MAKING THE CONGLOMERATE AND RELATED PRODUCTION METHOD

Abstract

A conglomerate for making road pavements is described, said conglomerate comprising a binder, preferably bitumen, a heavy inert material, preferably sand and/or gravel and/or filler, between 2.0% and 40% by weight of an elastomeric powder and/or granulate, and between 0.1% and 12% by weight of a thermoplastic polymer, preferably PE, PET or EVA in the form of granules or fibres; a method for making the conglomerate is also described, comprising the use of a compound which includes rubber powder and the polymer in suitable proportion.

Claims

1-28. (canceled)

29. A ready-to-use compound or pellet for making a conglomerate for road pavements, the ready-to-use compound or pellet comprising: an elastomeric material; and a thermoplastic polymer material in suitable proportions for making the conglomerate; wherein a sum of the elastomeric material and the thermoplastic polymer constitutes at least 95% by weight of the compound or pellet, the compound or pellet including at least 80% by weight of the elastomeric material, the remainder up to 100% including said thermoplastic polymer material and any additives.

30. The ready-to-use compound or pellet according to claim 29 wherein the elastomeric material is present in an amount of 83% and said thermoplastic polymer material and any additives are present in an amount of 17%.

31. The ready-to-use compound or pellet according to claim 29 wherein the elastomeric material is present in an amount of 80% to 85% by weight.

32. The ready-to-use compound or pellet according to claim 29 wherein the elastomeric material is present in an amount of at least 85% by weight.

33. The ready-to-use compound or pellet compound of claim 29 wherein the elastomeric material is present in an amount of 80% to 85% by weight and said thermoplastic polymer material and said any additives are present in an amount of correspondingly 15% to 20% by weight.

34. The ready-to-use compound or pellet according to claim 29 wherein said thermoplastic polymer material is any one of the following: PE, PET, PP, PS, PVC, or EVA.

35. The ready-to-use compound or pellet according to claim 31 wherein said thermoplastic polymer material is EVA.

36. The ready-to-use compound or pellet according to claim 29 wherein the elastomeric material is at least partially obtained from end-of-life tyres (ELTs).

37. The ready-to-use compound or pellet according to claim 29 wherein the elastomeric material is in the form of a fine powder having granules not exceeding 2 mm in size.

38. A method for making a conglomerate for road pavement, wherein: the conglomerate comprises a binder; a first component including a heavy inert material having a density greater than 2.0 Mg/m.sup.3; at least one elastomeric material in a form of a fine powder and/or granulate; at least one thermoplastic polymer in a form of granules or fibres; said at least one elastomeric material having a weight comprised between 2.0% and 40% of a total weight of the conglomerate, and said at least one thermoplastic polymer having a weight comprised between 0.1% and 12.0% of a total weight of the conglomerate; the method comprising: feeding components of the conglomerate into a mixer device, wherein the components of the conglomerate are fed into the mixer device according to the following sequence: first the heavy inert material; second the at least one thermoplastic polymer and the at least one elastomeric material, and third the binder; wherein the at least one elastomeric material and the at least one thermoplastic polymer are added into the mixer in a form of a compound including granules, which comprises said at least one elastomeric material and said at least one thermoplastic polymer in a desired proportion; wherein a sum of the at least one elastomeric material and the at least one thermoplastic polymer constitutes at least 95% by weight of said compound, the compound including at least 80% by weight of the elastomeric material, the remainder up to 100% including said thermoplastic polymer material and any additives.

39. The method according to claim 38 wherein said compound has a weight comprised between 3% and 15% of the total weight of the conglomerate.

40. The method according to claim 38 wherein, in the conglomerate, the at least one elastomeric material has a weight comprised between 2.0% and 12.0% of the total weight of the conglomerate.

41. The method according to claim 38 wherein, in the conglomerate, the at least one thermoplastic polymer has a weight comprised between 0.3% and 3.0% of the total weight of the conglomerate.

42. The method according to claim 38 for the making of a conglomerate for the realization of a connecting layer, wherein, in the conglomerate: the elastomeric material has a weight comprised between 2.0% and 9.0% of the total weight of the conglomerate; the polymer, which includes PE, has a weight comprised between 0.1% and 2.0% of the total weight of the conglomerate.

43. The method according to claim 38 wherein the conglomerate comprises recycled asphalt.

44. The method according to claim 43 wherein: the weight of the recycled asphalt in the conglomerate is between 5% and 60% of the total weight of the conglomerate and the conglomerate is intended for the realization of a wear layer of the road pavement.

45. The method according to claim 43, wherein: the weight of the recycled asphalt in the conglomerate is between 10% and 70% of the total weight of the conglomerate which is intended for the realization of a connecting layer of the road pavement.

46. The method according to claim 43, wherein: the weight of the recycled asphalt in the conglomerate is between 10% and 80% or between 10% and 90% of the total weight of the conglomerate which is intended respectively for the realization of a bottom layer or the realization of a base above the bottom layer of the road pavement.

47. The method according to claim 38 wherein the at least one thermoplastic polymer is at least partially obtained from recycling, preferably of PET bottles or Tetra Pak type containers.

48. The method according to claim 38 wherein the conglomerate comprises a light inert material with a density lower than 2.0 Mg/m.sup.3 and a bulk density lower than 1.2 Mg/m.sup.3, said light inert material having a weight comprised between 2% and 30% of the total weight of the conglomerate.

Description

PREFERRED EMBODIMENTS

[0029] According to a preferred formulation of conglomerate, in particular for making the wear layer of the road pavement, the weight of the elastomeric material is comprised between 2.0% and 12.0% of the total weight of the conglomerate, more preferably between 2.0% and 10.0% and even more preferably between 2.0% and 8.0%. The percentage amounts are always expressed in terms of weight unless otherwise specified.

[0030] The weight of the thermoplastic polymer is preferably comprised between 0.3% and 3.0% of the total weight of the conglomerate. Preferably, the polymer is PE, PET or EVA.

[0031] According to a preferred formulation of conglomerate intended to form a connecting layer, a base or a foundation layer of the road pavement, the elastomeric material has a weight comprised between 2.0% and 9.0% of the total weight of the conglomerate, and the polymer has a weight comprised between 0.1% and 2.0% of the total weight of the conglomerate.

[0032] According to an aspect of the invention, the conglomerate may comprise recycled asphalt which reduces the cost of the conglomerate. According to the common use the term “asphalt” refers to a bituminous conglomerate used for road pavement.

[0033] When recycled asphalt is used, the proportion of recycled asphalt compared to the total weight of the conglomerate may vary depending on the intended use of said conglomerate and more preferably is:

[0034] 5% to 60% to make a surface layer or wear layer of the road pavement;

[0035] 10% to 70% to make a connecting layer between two sections of the road pavement;

[0036] 10% to 80% in the base layers;

[0037] 10% to 90% in the foundation layers.

[0038] In a specific embodiment, the conglomerate comprises a fourth component consisting of a light inert material, preferably with a density less than 2.0 Mg/m.sup.3 and a bulk density less than 1.2 Mg/m.sup.3, and having a weight of 2% to 30% of the total weight of the conglomerate. In particular, said light inert material is used to increase the plasticity of the conglomerate and to improve laying even under a cold state. However, the conglomerate according to the invention may also be formulated in a version where the light inert material is absent.

[0039] The conglomerate according to the present invention may be made by means of a mixing method in which the components are inserted in the mixer device in the following sequence: first the heavy inert material; second the thermoplastic polymer and the elastomeric material, third the binder. The production of the conglomerate according to this method may be carried out in conventional plants suitable for the production of bituminous mixtures, which is an advantage because no special equipment is required. All the components are fed into the mixer following the sequence indicated above.

[0040] The elastomeric material and the thermoplastic polymer may be added, at least partially, during the manufacture of the conglomerate in the form of a compound consisting of granules or pellet. In one embodiment, all the elastomeric material and all the thermoplastic polymer used for the conglomerate are in the form of said compound or pellet.

[0041] In addition, according to another aspect of the mixing method, at least part of the elastomeric material and at least part of the thermoplastic polymer are aggregated in the form of a compound or pellet which advantageously contains the elastomeric material and the polymer in the desired proportion.

[0042] Preferably, the weight of the compound or pellet is comprised between, for example, 3% and 15% of the total weight of the conglomerate.

[0043] It should be noted that the proportions have been indicated as percentage; in the field for an immediate understanding, reference is often made to kg per tonne of conglomerate, where 1% corresponds to 10 kg per tonne. Therefore, for example a range from 2% to 12% corresponds to a weight from 20 kg to 120 kg per tonne.

[0044] Preferably, in the various embodiments of the invention, the binder (filler) content is not more than 12% by weight.

[0045] According to a further aspect of the invention, a ready-to-use compound or pellet is provided for making a conglomerate for road pavements, which contains the elastomeric material and the polymer in the desired proportions for a specific conglomerate formulation (for example for one of the uses already mentioned above).

[0046] Preferably, the elastomeric material in the compound has a weight quantity double or greater than the polymer.

[0047] Preferably, the compound comprises only the elastomeric material and the polymer without additives. The additives may be added to improve the workability, its dispersibility or to improve the final quality of the conglomerate. The compound may comprise at least 95% by weight which is the sum of the elastomeric material and the polymer, while the remaining 5% (or less) being represented by the aforementioned additives.

[0048] For example, the compound may comprise at least 70% by weight of elastomeric material, the remaining amount which makes up 100% consisting of the polymer and any additives. In a preferred embodiment, the compound comprises from 80% to 85% by weight of elastomeric material and correspondingly from 20% to 15% by weight of polymer and any additives. In a particularly preferred embodiment, the compound comprises 83% of elastomeric material and 17% of polymer and any additives.

[0049] The polymer in the compound may comprise any one of the following: PET, PP, PS, PVC, EVA. The elastomeric material in the compound is advantageously obtained at least partially from end-of-life tyres.

[0050] The elastomeric material in the compound is preferably in the form of a fine powder having granules not exceeding 2 mm in size.

EXAMPLE

[0051] By way of example, the composition of a wear layers conglomerate according to the present invention is provided below; the Applicant has found excellent results in terms of noise reduction of the road pavement made with this composition and also in term of physical-mechanical characteristics, such as resistance to permanent deformation, resistance to fatigue and limited material loss.

[0052] Composition of the conglomerate for wear layers:

TABLE-US-00001 Filler 4% Sand 0-2 mm 4% Sand 2-4 mm 29%  Stone chippings 4-8 mm 47%  Rubber powder 7% Recycled polyethylene in granular form 1% Bitumen 8%