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(11) | EP 1 078 129 B1 |
| (12) | EUROPEAN PATENT SPECIFICATION |
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| (54) |
DOUBLE LAYER DRAINING AND SOUND-ABSORBING WEARING COURSE DOPPELLAGIGE, WASSERDURCHLÄSSIGE UND LÄRMMINDERNDE DECKSCHICHT REVETEMENT DE SURFACE BICOUCHE INSONORISANT ET DRAINANT ET SES PROCEDES ET MOYENS DE PREPARATION |
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| Note: Within nine months from the publication of the mention of the grant of the European patent, any person may give notice to the European Patent Office of opposition to the European patent granted. Notice of opposition shall be filed in a written reasoned statement. It shall not be deemed to have been filed until the opposition fee has been paid. (Art. 99(1) European Patent Convention). |
[0001] The present invention relates to a double layer draining and sound-absorbing wearing course, its use in motor racing circuits and road paving, means and method for its preparation.
[0002] The wearing courses used in motor racing circuits, highways, national and urban roads with heavy traffic require good mechanical properties, a high grip and surface regularity. These properties are traditionally obtained using "closed" wearing courses, i.e. with reduced content of residual voids. This solution however is of no help during rainfall.
[0003] In fact, the rain stagnates on the surface with a consequent reduction in tyre grip (aquaplaning) also causing water spray which reduces the visibility.
[0004] In order to solve these drawbacks, "open" wearing courses, also called draining pavements, were developed, whose use in road paving began on a wide scale towards the mid-eighties' and was applied to highways, national and urban roads.
[0005] Draining pavements as disclosed in EP-A-0 381 903 are mainly characterized by a high percentage of residual voids (>18%) obtained by adopting inert products with a discontinuous granulometric curve which ensures, with respect to a closed pavements, the following advantages:
- improvement in tyre grip on wet surfaces;
- decrease in water spray generated by tyres in the case of rain;
- elimination of aquaplaning;
- reduction in the sound level outside the car owing to the absorption of acoustic energy;
- reduction in the luminous reflection at night.
[0006] With respect to closed wearing courses, however, these pavements have a reduced structural resistance and a tendency towards rapid fouling, which blocks the voids and consequently reduces the draining capacity.
[0007] The use of these draining pavements consequently does not seem to be very suitable for particular applications, such as for example, the paving of motor racing circuits, on which there are greater problems of structural resistance and fouling.
[0008] It has now been found that the drawbacks of the known art discussed above can be overcome by the use of an open wearing course consisting of two layers have different thicknesses and different granulometric curves of the stone aggregates (inert products).
[0009] In particular, the use of modified bitumens having a reduced thermal susceptibility, high elasticity, high tack to inert products and good aging resistance, combined with this double-layered structure, allows the following advantages to be obtained:
(a) an improved crushing strength with respect to the traditional draining pavements;
(b) a reduction in the sound impact non only externally but, surprisingly, also inside the vehicle;
(c) a draining capacity which decreases more slowly with time;
(d) a lesser tendency towards fouling (pore blockage).
[0010] The upper layer, in fact, obtained with stone agglomerates having reduced dimensions, owing to its texture, acts as a sieve for the impurities present on the road surface. In this way the larger impurities are withheld on the surface without blocking the pores and can be mechanically removed by the passage of vehicles. The finer impurities penetrate through both layers and can be easily eliminated by rain water through the larger holes of the lower layer.
[0011] In accordance with this, the present invention relates to a double layer draining and sound-absorbing wearing course as defined by claim 1 made up of:
(1) an upper layer having a thickness ranging from 2 to 5 cm consisting of a bituminous conglomerate which comprises:
(a) a stone aggregate consisting of elements with dimensions ranging from 0.075 to 10 mm in a quantity ranging from 88 to 98% by weight;
(b) a filler in a quantity ranging from 2 to 12% by weight;
(c) a bituminous ligand having the characteristics indicated in table 2 in a quantity ranging from 3.5 to 5.5% by weight with respect to the sum of components (a) and (b) and
(2) a lower layer having a thickness ranging from 2 to 7 cm consisting of a bituminous conglomerate which comprises:
(a') a stone aggregate consisting of elements with dimensions ranging from 0.125 to 20 mm in a quantity ranging from 85 to 98% by weight;
(b') a filler in a quantity ranging from 2 to 15% by weight;
(c') a bituminous ligand having the characteristics indicated in table 2 in a quantity ranging from 3.5 to 5.5% by weight with respect to the sum of components (a') and (b').
[0012] The upper layer of the draining and sound-absorbing wearing course preferably has a thickness ranging from 2.5 to 4 cm and consists of:
(a) a stone aggregate consisting of elements with dimensions ranging from 0.075 to 7.1 mm in a quantity ranging from 90 to 95% by weight;
(b) a filler in a quantity ranging from 5 to 10% by weight;
(c) a bituminous ligand having the characteristics indicated in table 2 in a quantity ranging from 4 to 5% by weight with respect to the sum of components (a) and (b).
[0013] The lower layer of the draining and sound-absorbing wearing course preferably has a thickness ranging from 3 to 7 cm and consists of:
(a') a stone aggregate consisting of elements with dimensions ranging from 0.125 to 15 mm in a quantity ranging from 90 to 95% by weight;
(b') a filler in a quantity ranging from 5 to 10% by weight;
(c') a bituminous ligand having the characteristics indicated in table 2 in a quantity ranging from 4 to 5% by weight with respect to the sum of components (a') and (b').
[0014] The stone aggregates which can be used consist of healthy, hard granular elements, in a non-flattened, elongated or lenticular form, clean and without foreign matter, according to regulation C.N.R. 139/1992.
[0015] These aggregates typically have the characteristics indicated in table 1.
| Properties | Regulation | Specification |
| Quantity of crushed product | CNR 34/73 | 100% |
| Weight loss (Los Angeles test) | CNR 140/92 | <18% |
| Accelerated levigation coefficient (A.L.C.) | CNR 95/84 | > 0.45 |
| Flattening coefficient | CNR 95/84 | < 1.58 |
| Form coefficient | CNR 95/84 | < 3 |
| Sensitivity to freezing | CNR 80/80 | < 20% |
| Stripping in water at 40°C | CNR 138/92 | 0% |
[0016] The fillers are those conventionally used for the production of conglomerates. They are generally powders with a particle size of less than 0.125 mm.
[0017] Examples of fillers suitable for the purpose of the present invention comprise calcium carbonate and cement.
[0018] The bituminous ligand is selected from modified bitumens having the characteristics indicated in table 2.
| Properties | Regulation | Specification |
| Penetration at 25°C [0.1 mm] | CNR 24/71 | 30-90 |
| Softening point [°C] | CNR 35/73 | > 60 |
| Fraass Breaking point [°C] | CNR 43/74 | < -15 |
| Elastic flow at 25°C [%] | DIN 52013 | > 50 |
[0019] A modified bitumen having a softening point of over 80°C and an elastic flow at 25°C higher than 80%, is preferably used.
[0020] Particularly preferred is a modified bitumen containing SBS (styrene-butadiene-styrene) polymers obtained, for example, as described in U.S. patent 5,756,563, or, for example of the type sold by AGIP PETROLI S.p.A. under the trade-name of ELIFLEX®.
[0021] Some of the characteristics of the pavements of the present invention are indicated in table 3.
| Properties | Regulation | Specific. |
| Marshall stability | CNR B.U. Nr.30 | > 7kN |
| Marshall residual holes | CNR B.U. Nr.30 | > 20% |
| Permeability in situ | -- | >20 l/min |
| Cantabro weight loss (300 revs) | -- | < 15% |
[0022] The sound-absorbency characteristics, determined by means of sound level measurements, not only indicate a decrease in noise outside the vehicle, but also a reduction thereof inside the vehicle of over 3 decibel.
[0023] The bituminous conglomerate is prepared under heating in a suitable plant by putting the stone aggregate, the bitumen and filler in contact with each other in the appropriate quantities.
[0024] The temperature and mixing time are generally selected in relation to the materials and climatic conditions during the laying. In any case, the mixing conditions are selected so as to obtain a conglomerate having an adequate laying temperature to allow effective rolling.
[0025] The pavement of the present invention is prepared by:
(i) the laying of a first lower layer having a thickness ranging from 2 to 7 cm and consisting of a bituminous conglomerate which comprises:
(a') a stone aggregate consisting of elements with dimensions ranging from 0.125 to 20 mm in a quantity ranging from 85 to 98% by weight;
(b') a filler in a quantity ranging from 2 to 15% by weight;
(c') a bituminous ligand having the characteristics indicated in table 2 in a quantity ranging from 3.5 to 5.5% by weight with respect to the sum of components (a') and (b'); and
(ii) the curing of this first layer; and
(iii) the laying on said first layer of a second upper layer having a thickness ranging from 2 to 5 cm consisting of a bituminous conglomerate which comprises:
(a) a stone aggregate consisting of elements with dimensions ranging from 0.075 to 10 mm in a quantity ranging from 88 to 98% by weight;
(b) a filler in a quantity ranging from 2 to 12% by weight;
(c) a bituminous ligand having the characteristics indicated in table 2 in a quantity ranging from 3.5 to 5.5% by weight with respect to the sum of components (a) and (b).
[0026] In practice, before proceeding with the laying of the conglomerate, all the usual operations are effected for its preparation, consisting in milling the damaged layer, profiling and cleaning.
[0027] A water-proofing membrane is then laid on top of the base layer to protect it from the infiltration of rain water.
[0028] This membrane consists of modified bitumen, preferably a bitumen identical to that used for the preparation of the conglomerates, suitably saturated with grit or filler.
[0029] The bituminous conglomerate is then laid on top of this membrane to obtain a first lower layer having the characteristics described above.
[0030] After laying the lower draining layer, it is advisable to allow a curing time of not less than two days before proceeding with the laying of the upper layer.
a) a stone aggregate ,
b) a filler,
c) a bituminous ligand,
said double layer wearing course being characterised in that it consists of:1) an upper layer having a thickness ranging from 2 to 5 cm consisting of a bituminous conglomerate which comprises:
a) a stone aggregate consisting of elements with dimensions ranging from 0.075 to 10 mm in a quantity ranging from 88 to 98% by weight;
b) a filler in a quantity ranging from 2 to 12% by weight;
c) a bituminous ligand having the characteristics
| penetration at 25°C [0.1mm] | CNR 24/71 | 30-90, |
| Softening point [°C] | CNR 35/73 | > 60, |
| Fraas Breaking point [°C] | CNR 43/74 | < -15, |
| Elastic flow at 25° [%] | DIN 52013 | > 50 |
2) a lower layer having a thickness ranging from 2 to 7 cm consisting of a bituminous conglomerate which comprises:
a') a stone aggregate consisting of elements with dimensions ranging from 0.125 to 20 mm in a quantity ranging from 85 to 98% by weight;
b') a filler in a quantity ranging from 2 to 15% by weight;
c') a bituminous ligand having the characteristics indicated at point c) in a quantity ranging from 3.5 to 5.5% by weight with respect to the sum of components a') and b').
a) a stone aggregate consisting of elements with dimensions ranging from 0.075 to 7.1 mm in a quantity of 90 to 95% by weight;
b) a filler in a quantity ranging from 5 to 10% by weight;
c) a bituminous ligand having the characteristics indicated in claim 1 in a quantity ranging from 4 to 5% by weight with respect to the sum of components a) and b).
a) a stone aggregate consisting of elements with dimensions ranging from 0.125 to 15 mm in a quantity of 90 to 95% by weight;
b) a filler in a quantity ranging from 5 to 10% by weight;
c) a bituminous ligand having the characteristics indicated in claim 1 in a quantity ranging from 4 to 5% by weight with respect to the sum of components a) and b).
i) the laying of a first lower layer having a thickness ranging from 2 to 7 cm and consisting of a bituminous conglomerate which comprises:
a') a stone aggregate consisting of elements with dimensions ranging from 0.125 to 20 mm in a quantity ranging from 85 to 98% by weight;
b') a filler in a quantity ranging from 2 to 15% by weight;
c') a bituminous ligand having the characteristics
| penetration at 25°C [0.1mm] | CNR 24/71 | 30-90, |
| Softening point [°C] | CNR 35/73 | > 60, |
| Fraas Breaking point [°C] | CNR 43/74 | < -15, |
| Elastic flow at 25° [%] | DIN 52013 | > 50 |
ii) the curing of this first layer; and
iii) the laying on said first layer of a second upper layer having a thickness ranging from 2 to 5 cm consisting of a bituminous conglomerate which comprises:
a) a stone aggregate consisting of elements with dimensions ranging from 0.075 to 10 mm in a quantity ranging from 88 to 98% by weight;
b) a filler in a quantity ranging from 2 to 12% by weight;
c) a bituminous ligand having the characteristics indicated at point c') in a quantity ranging from 3.5 to 5.5% by weight with respect to the sum of components a) and b).
a') a stone aggregate consisting of elements with dimensions ranging from 0.125 to 15 mm in a quantity ranging from 90 to 95% by weight;
b') a filler in a quantity ranging from 5 to 10% by weight;
c') a bituminous ligand having the characteristics indicated in claim 9 in a quantity ranging from 4 to 5% by weight with respect to the sum of components a') and b').
a) a stone aggregate consisting of elements with dimensions ranging from 0.075 to 7.1 mm in a quantity ranging from 90 to 95% by weight;
b) a filler in a quantity ranging from 5 to 10% by weight;
c) a bituminous ligand having the characteristics indicated in claim 9 in a quantity ranging from 4 to 5% by weight with respect to the sum of components a) and b).
a) einen Gesteinszuschlagstoff;
b) einen Füllstoff; und
c) ein bituminöses Bindemittel
umfasst; und wobei die doppellagige Verschleißschicht dadurch gekennzeichnet ist, dass sie besteht aus:1) einer oberen Lage mit einer Dicke im Bereich von 2 bis 5 cm bestehend aus einem bituminösen Gemisch, welches umfasst:
a) einen Gesteinszuschlagstoff bestehend aus Elementen mit Abmessungen im Bereich von 0,075 bis 10 mm in einer Menge im Bereich von 88 bis 98 Gew.-%;
b) einen Füllstoff in einer Menge im Bereich von 2 bis 12 Gew.-%; und
c) ein bituminöses Bindemittel mit den Charakteristika
| Penetration bei 25 °C [0,1 mm] | CNR 24/71 | 30-90, |
| Erweichungspunkt [°C] | CNR 35/73 | > 60, |
| Fraaß-Brechpunkt [°C] | CNR 43/74 | < -15, |
| Elastische Verformung bei 25 °C [%] | DIN 52013 | > 50 |
2) einer unteren Lage mit einer Dicke im Bereich von 2 bis 7 cm bestehend aus einem bituminösen Gemisch, welches umfasst:
a') einen Gesteinszuschlagstoff bestehend aus Elementen mit Abmessungen im Bereich von 0,125 bis 20 mm in einer Menge im Bereich von 85 bis 98 Gew.-%;
b') einen Füllstoff in einer Menge im Bereich von 2 bis 15 Gew.-%; und
c') ein bituminöses Bindemittel mit den unter Punkt c) angegebenen Charakteristika in einer Menge im Bereich von 3,5 bis 5,5 Gew-% bezogen auf die Summe der Komponenten a') und b').
a) einem Gesteinszuschlagstoff bestehend aus Elementen mit Abmessungen im Bereich von 0,075 bis 7,1 mm in einer Menge von 90 bis 95 Gew.-%;
b) einem Füllstoff in einer Menge im Bereich von 5 bis 10 Gew-%; und
c) einem bituminösen Bindemittel mit den in Anspruch 1 angegebenen Charakteristika in einer Menge im Bereich von 4 bis 5 Gew.-% bezogen auf die Summe der Komponenten a) und b).
a) einem Gesteinszuschlagstoff bestehend aus Elementen mit Abmessungen im Bereich von 0,125 bis 15 mm in einer Menge von 90 bis 95 Gew-%;
b) einem Füllstoff in einer Menge im Bereich von 5 bis 10 Gew.-%; und
c) einem bituminösen Bindemittel mit den in Anspruch 1 angegebenen Charakteristika in einer Menge im Bereich von 4 bis 5 Gew.-% bezogen auf die Summe der Komponenten a) und b).
i) das Verlegen einer ersten, unteren Lage mit einer Dicke im Bereich von 2 bis 7 cm, bestehend aus einem bituminösen Gemisch, welches umfasst:
a') einen Gesteinszuschlagstoff bestehend aus Elementen mit Abmessungen im Bereich von 0,125 bis 20 mm in einer Menge im Bereich von 85 bis 98 Gew.-%;
b') einen Füllstoff in einer Menge im Bereich von 2 bis 15 Gew-%; und
c') ein bituminöses Bindemittel mit den Charakteristika
| Penetration bei 25 °C [0,1 mm] | CNR 24/71 | 30-90, |
| Erweichungspunkt [°C] | CNR 35/73 | > 60, |
| Fraaß-Brechpunkt [°C] | CNR 43/74 | < -15, |
| Elastische Verformung bei 25 °C [%] | DIN 52013 | > 50 |
ii) das Aushärten dieser ersten Lage; und
iii) das Verlegen einer zweiten, oberen Lage mit einer Dicke im Bereich von 2 bis 5 cm auf die erste Lage, bestehend aus einem bituminösen Gemisch, welches umfasst:
a) einen Gesteinszuschlagstoff bestehend aus Elementen mit Abmessungen im Bereich von 0,075 bis 10 mm in einer Menge im Bereich von 88 bis 98 Gew.-%;
b) einen Füllstoff in einer Menge im Bereich von 2 bis 12 Gew.-%; und
c) ein bituminöses Bindemittel mit den unter Punkt c') angegebenen Charakteristika in einer Menge im Bereich von 3,5 bis 5,5 Gew.-% bezogen auf die Summe der Komponenten a) und b).
a') einem Gesteinszuschlagstoff bestehend aus Elementen mit Abmessungen im Bereich von 0,125 bis 15 mm in einer Menge im Bereich von 90 bis 95 Gew.-%;
b') einem Füllstoff in einer Menge im Bereich von 5 bis 10 Gew.-%; und
c') einem bituminösen Bindemittel mit den in Anspruch 9 angegebenen Charakteristika in einer Menge im Bereich von 4 bis 5 Gew.-% bezogen auf die Summe der Komponenten a') und b').
a) einem Gesteinszuschlagstoff bestehend aus Elementen mit Abmessungen im Bereich von 0,075 bis 7,1 mm in einer Menge im Bereich von 90 bis 95 Gew.-%;
b) einem Füllstoff in einer Menge von 5 bis 10 Gew.-%; und
c) einem bituminösen Bindemittel mit den in Anspruch 9 angegebenen Charakteristika in einer Menge im Bereich von 4 bis 5 Gew.-% bezogen auf die Summe der Komponenten a) und b).
a) un agrégat de pierre,
b) une charge,
c) un ligand bitumineux,
ledit revêtement de surface bicouche étant caractérisé en ce qu'il est constitué par :1) une couche supérieure ayant une épaisseur allant de 2 à 5cm, constituée d'un conglomérat bitumineux qui comprend :
a) un agrégat de pierre constitué d'éléments de dimensions allant de 0,075 à 10 mm en une quantité allant de 88 à 98 % en poids ;
b) une charge en une quantité allant de 2 à 12 % en poids ;
c) un ligand bitumineux ayant les caractéristiques suivantes :
| pénétration à 25 °C [0,1 mm] | CNR24/71 | 30 à 90, |
| point de ramollissement [°C] | CNR 35/73 | > 60, |
| température d'écaillage Fraas [°C] | CNR 43/74 | < -15, |
| flux élastique à 25° [%] | DIN 52013 | > 50 |
2) une couche inférieure ayant une épaisseur allant de 2 à 7 cm constituée d'un conglomérat bitumineux qui comprend :
a') un agrégat de pierre constitué d'éléments de dimensions allant de 0,125 à 20 mm en une quantité allant de 85 à 98 % en poids ;
b') une charge en une quantité allant de 2 à 15 % en poids ;
c') un ligand bitumineux ayant les caractéristiques indiquées au point c) en une quantité allant de 3,5 à 5,5 % en poids en ce qui concerne la somme des composants a') et b').
a) un agrégat de pierre constitué d'éléments de dimensions allant de 0,075 à 7,1 mm en une quantité de 90 à 95 % en poids ;
b) une charge en une quantité allant de 5 à 10 % en poids ;
c) un ligand bitumineux ayant les caractéristiques indiquées dans la revendication 1 en une quantité allant de 4 à 5 % en poids en ce qui concerne la somme des composants a) et b).
a) un agrégat de pierre constitué d'éléments de dimensions allant de 0,125 à 15 mm en une quantité de 90 à 95 % en poids ;
b) une charge en une quantité allant de 5 à 10 % en poids ;
c) un ligand bitumineux ayant les caractéristiques indiquées dans la revendication 1 en une quantité allant de 4 à 5 % en poids en ce qui concerne la somme des composants a) et b).
i) le dépôt d'une première couche inférieure ayant une épaisseur allant de 2 à 7 cm et étant constituée d'un conglomérat bitumineux qui comprend :
a') un agrégat de pierre constitué d'éléments de dimensions allant de 0,125 à 20 mm en une quantité allant de 85 à 98 % en poids ;
b') une charge en une quantité allant de 2 à 15 % en poids ;
c') un ligand bitumineux ayant les caractéristiques suivantes :
| pénétration à 25 °C [0,1 mm] | CNR24/71 | 30 à 90, |
| point de ramollissement [°C] | CNR 35/73 | > 60, |
| température d'écaillage Fraas [°C] | CNR 43/74 | < -15, |
| flux élastique à 25° [%] | DIN 52013 | > 50 |
ii) la vulcanisation de la première couche ; et
iii) le dépôt sur ladite première couche d'une seconde couche supérieure ayant une épaisseur allant de 2 à 5 cm constituée d'un conglomérat bitumineux qui comprend :
a) un agrégat de pierre constitué d'éléments de dimensions allant de 0,075 à 10 mm en une quantité allant de 88 à 98 % en poids ;
b) une charge en une quantité allant de 2 à 12 % en poids ;
c) un ligand bitumineux ayant les caractéristiques indiquées au point c') en une quantité allant de 3,5 à 5,5 % en poids en ce qui concerne la somme des composants a) et b).
a') un agrégat de pierre constitué d'éléments de dimensions allant de 0,125 à 15 mm en une quantité allant de 90 à 95 % en poids ;
b') une charge en une quantité allant de 5 à 10 % en poids ;
c') un ligand bitumineux ayant les caractéristiques indiquées dans la revendication 9 en une quantité allant de 4 à 5 % en poids en ce qui concerne la somme des composants a') et b').
a) un agrégat de pierre constitué d'éléments de dimensions allant de 0,075 à 7,1 mm en une quantité allant de 90 à 95 % en poids ;
b) une charge en une quantité allant de 5 à 10 % en poids ;
c) un ligand bitumineux ayant les caractéristiques indiquées dans la revendication 9 en une quantité allant de 4 à 5 % en poids en ce qui concerne la somme des composants a) et b).