|
(11) | EP 0 924 344 A1 |
| (12) | EUROPEAN PATENT APPLICATION |
|
|
|
|
|||||||||||||||||||||||
| (54) | Rail track constuction |
| (57) The invention relates to a method for laying rails (2), such as, for example, tram
rails, in a pavement having a road surface (5) for traffic. The rails are laid in
a fixing course (4) that has been formed from a porous starting material having a
relatively high voids content, which voids are filled with a hardening reinforcing
medium. By this means the rails can be installed in a stable manner without the use
of sleepers or tie bars. The starting material can be applied in a simple manner,
for example by hot spreading. After the reinforcing medium has been applied, a construction
which has high dimensional stability in the horizontal direction is formed in which
the rails can be accurately positioned. The rails (2) can be sunk in grooves (3) and
fixed in place by means of a casting material (6). The fixing course (4) preferably
comprises very open asphalt concrete (VOAC) having a voids content of at least 20
%, preferably between 25 % and 30 %. The reinforcing medium used can be a cement-based
slurry. |
[0001] The invention relates to a method for laying rails in a pavement having a road surface for traffic, wherein the rails are laid in the pavement such that they are sunken with respect to the road surface.
[0002] European Patent Application number EP-A 0 737 778 in the name of the Applicant discloses a rail track construction with which two parallel rails are laid in grooves in a concrete or steel foundation. A layer of sound-absorbent material such as, for example, very open asphalt concrete (VOAC) is applied between and alongside the rails. How the rails are fixed in the grooves is not shown in more detail. Fixing of the rails is problematical since, on the one hand, a high degree of fixation is desired and, on the other hand, a sound-damping effect must also be obtained and the transfer of vibration from the rails to the foundation, which for example is made of concrete, must be restricted. The construction disclosed in EP-A 0 737 778 is not suitable for use in a road surface for traffic, such as, for example, in the case of tram rails laid in the road. One aim of the present invention is therefore to provide a method for laying rails in a pavement with which stable positioning of the rails can take place in a simple and inexpensive manner. A further aim of the present invention is to provide a method for forming a rail construction which is well integrated in the paving construction of the pavement with relatively few transitions so that a level road surface is retained. A further aim of the present invention is to provide a rail construction wherein adequate vibration damping of the rails is obtained, wherein fixing of the position in the long term under static loads is guaranteed and wherein in the event of replacement the rails can be removed relatively easily.
[0003] To this end the method according to the present invention is characterised in that the rails are laid in a fixing course that has been formed from a porous starting material having a relatively high voids content, which voids are filled with a hardening reinforcing medium.
[0004] When applying the layer of starting material the latter can be rendered plastic and applied simply with the aid of, for example, known asphalt spreading techniques. The voids in the starting material are then filled with a hardening reinforcing medium so that a fixing course is formed which has very high lateral dimensional stability. As a result the rails are accurately fixed and sleepers, tie bars or other fixing means to join the rails to one another can be dispensed with. Furthermore the method according to the present invention saves costs because the major part of the rail construction is formed by the road paving.
[0005] It is possible first to lay the rails in the starting material, for cxample by cutting grooves in the latter when it is applied or by making said grooves subsequently by sawing or milling and then applying the reinforcing medium. However, it is also possible first to form the fixing course by applying a reinforcing medium and then to lay the rails in preformed and hardened grooves.
[0006] Preferably the space between the rails and the wall of the grooves is filled with a casting material, such as a casting material based on plastics, optionally with vibration-damping fillers, or a casting material composed of asphalt.
[0007] Preferably, the staring material used for the fixing course is very open asphalt concrete (VOAC) having a voids content of at least 20 %, preferably between 25 % and 30 %. It has been found that such a course allows good penetration of the hardening reinforcing medium and that a highly advantageous lateral dimensional stability is obtained by this means. Preferably, the reinforcing medium comprises a cement-based slurry which has good penetration in very open asphalt concrete.
[0008] The thickness of the fixing course is preferably between 5 cm and 15 cm and in a preferred embodiment forms the road surface for the traffic. For alignment in the vertical direction a roadbase comprising asphalt granulate cement formed from recycled asphalt concrete with cement (CRAC) and/or asphalt concrete with minerals such as crushed aggregate or chippings (for example RAC) is preferably used. A basecourse of asphalt concrete with minerals (RAC) can be used on top of this foundation and the fixing course applied on top of this. With a construction of this type some flexibility in the vertical direction is retained, as a result of which cracking in the event of slight settlement is counteracted.
[0009] With the method according to the present invention transverse forces of various magnitude, such as, for example, transverse forces which arise when taking bends, can be absorbed by varying the thickness of the fixing course. The thickness of the roadbase is partly dependent on the sub-grade conditions and on the volume of traffic.
[0010] The invention will be explained in more detail with reference to the single figure, which shows a diagrammatic cross-section of a tram rail construction according to the present invention. The figure shows a tram rail construction 1 having two rails 2, 2'. each of which has been laid in an individual groove 3. The groove 3 has been made in a fixing course 4 according to the present invention which has been formed from very open asphalt concrete with a hardened cement-based reinforcing medium therein. The fixing course 4 forms a road surface 5 for traffic, the rails 2, 2' being laid flush with the road surface 5.
[0011] The rails 2, 2' have been fixed in the grooves 3 by means of a plastic casting material 6, which, for example, is formed from a plastic, optionally with vibration-damping fillers. Below the fixing course there is a basecourse 7 formed from bitumen with crushed aggregate or chippings of a standard composition. A roadbase 8 is used below the basecourse 7, which roadbase 8 can have a composition similar to that of the basecourse 7 or can be formed from crushed used asphalt concrete to which about 4 % by wt cement has been added (CRushed Asphalt Cement or CRAC) which has been made up in accordance with generally known guidelines. Using the method according to the present invention rails can be laid in a pavement in a simple manner, without using sleepers, tie bars or other fixing means, such that a rail construction is obtained that is well integrated in the road surface with a minimum of transitions and minimum unevenness. By using the hardening reinforcing medium according to the present invention the rails 2, 2' can be anchored in a stable manner without the use of sleepers or other tie elements between the rails.
1. Method for laying rails in a pavement having a road surface for traffic, wherein the
rails are laid in the pavement such that they are sunken with respect to the road
surface, characterised in that the rails are laid in a fixing course that has been
formed from a porous starting material having a relatively high voids content, which
voids are filled with a hardening reinforcing medium.
2. Method according to Claim 1, characterised in that grooves, in which the rails can
be laid, are first made in the starting material of the fixing course, after which
the reinforcing medium is applied.
3. Method according to Claim 1, characterised in that the fixing course is first formed
and in that the grooves are made after the reinforcing medium has hardened.
4. Method according to Claim 2 or 3, characterised in that after laying the rails in
the grooves the space between the rails and the wall of the grooves is filled with
a casting material.
5. Method according to Claim 1, 2, 3 or 4, characterised in that the reinforcing medium
comprises a cement-based slurry.
6. Method according to one of the preceding claims, characterised in that the fixing
course comprises very open asphalt concrete (VOAC) having a voids content of at least
20 %, preferably between 25 % and 30 %.
7. Method according to one of the preceding claims, characterised in that the casting
material comprises a setting plastic or asphalt.
8. Method according to one of the preceding claims, characterised in that two parallcl
rails are laid without joining said rails to one another by sleepers.
9. Method according to one of the preceding claims, characterised in that the thickness
of the fixing course is between 5 cm and 15 cm.
10. Method according to one of the preceding claims, characterised in that the fixing
course forms the road surface.
11. Method according to one of the preceding claims, characterised in that the fixing
course is applied on top of a roadbase comprising recycled asphalt concrete with cement
(CRAC) and/or asphalt concrete with minerals such as crushed aggregate or chippings
(RAC).
12. Method according to Claim 11, characterised in that paving of asphalt concrete with
minerals such as crushed aggregate or chippings is applied on top of the roadbase.
13. Method according to one of the preceding claims, characterised in that the grooves
for laying the rails extend partially into the basecourse located beneath the fixing
course.
14. Method according to one of the preceding claims, characterised in that the rails (2,
2') are not joined to another by tie elements.