Concrete based reinforced road structure covered by asphalt

Abstract

Concrete based reinforced road structure covered by asphalt that comprises a basic layer (1) made of concrete with a substantially horizontal upper surface and placed directly or through a subconstruction on the ground and at least one mould cover layer (2) thereon made of asphalt, and support elements (3) positioned between the basic layer (1) and the cover layer (2), wherein the support elements (3) are inserted in a predetermined depth in the basic layer (1) prior to the setting thereof so that they are partially projecting out of the basic layer (1) in normal direction to the upper surface, and the projecting portion provides protection to the cover layer (2) against being displaced relative to the basic layer (1) under loads to which the road is exposed, and the support elements (3) are flat stripes with walls being substantially normal to the surface of the basic layer (1) and comprising subsequent sections with differing directions to form respective meandering lines.

Claims

1. A reinforced road structure comprising a basic layer made of concrete having a substantially horizontal upper surface and which is placed directly or through a subconstruction while the concrete is in a non-solidified pasty state on the ground, support elements having portions that extend through the upper surface into the concrete at a predetermined depth, the support elements having projecting portions partially projecting out from the basic layer in a direction normal to the upper surface, and the support elements having side walls defined by flat cross sections, the support elements forming a generally serpentine shape along their length, at least one cover layer over the basic layer, the at least one cover layer comprised of asphalt, wherein the projecting portions of the support elements partially projecting out of the basic layer are embedded in and covered by the at least one cover layer, wherein the projecting portions provide protection to the cover layer against being displaced relative to the basic layer when the road structure is under loads to which the road structure is exposed.

2. The reinforced road structure as claimed in claim 1, wherein the support elements extend beside each other and along certain of the flat cross sections the support elements are interconnected to thereby define together an array of closed shapes.

3. The reinforced road structure as claimed in claim 1, wherein the support elements have respective openings that extend till the upper surface of the basic layer, the respective openings having lower edges, and respective fold-out cut tabs at the lower edges so that the support elements have their projecting portions and their portions that extend through the upper surface into the concrete at a predetermined depth.

4. The reinforced road structure as claimed in claim 1, wherein the cover layer comprises gravel pieces made of stone, and the support elements extend out from the upper surface of the basic layer at least as high as the half of the average size of the gravel pieces.

5. The reinforced road structure as claimed in claim 1, wherein the support elements are arranged beside each other to form respective regular shapes which are connected to each other.

6. The reinforced road structure as claimed in claim 2, wherein the closed shapes are selected from the group consisting of triangle, square, circle or hexagon.

7. The reinforced road structure as claimed in claim 2, wherein respective openings are provided in the support elements that extend till the upper surface of the basic layer, the respective openings having lower edges, and respective fold-out cut tabs at the lower edges so that the support elements have their projecting portions and their portions that extend through the upper surface into the concrete at a predetermined depth.

8. The reinforced road structure as claimed in claim 2, wherein the cover layer comprises gravel pieces made of stone, and the support elements extend out from the upper surface of the basic layer at least as high as the half of the average size of the gravel pieces.

9. The reinforced road structure as claimed in claim 3, wherein the closed shapes are selected from the group consisting of triangle, square, circle or hexagon.

10. The reinforced road structure as claimed in claim 1, wherein the support elements are made of iron or steel.

11. A reinforced road structure comprising a basic layer made of concrete having a substantially horizontal upper surface and which is placed directly or through a subconstruction on the ground, support elements extending through the upper surface into the basic layer at a predetermined depth, said support elements having projecting portions that partially project out of the basic layer in normal direction to the upper surface, said support elements comprising flat stripes with walls substantially normal to the upper surface of the basic layer, said flat stripes including sections with differing directions to thereby form respective meandering lines, and said support elements having upper sides with a wider upper rim, at least one cover layer comprised of asphalt over the basic layer, wherein the support elements partially projecting out of the basic layer are embedded in and covered by the at least one cover layer, wherein the projecting portion provides protection to the cover layer against being displaced relative to the basic layer when the road structure is under loads to which the road structure is exposed.

12. A reinforced road surface obtained by forming a basic layer from concrete, while the concrete is in a non-solidified state, directly or through a subconstruction on the ground, the basic layer having a substantially horizontal upper surface, inserting support elements from above through the upper surface into the basic layer at a predetermined depth before the concrete sets, wherein the support elements have projecting portions that partially project out of the basic layer in normal direction to the upper surface, and wherein the support elements comprise flat stripes having walls substantially normal to the surface of the basic layer, and said flat stripes comprising sections having differing directions to thereby form respective meandering lines, forming a hardened basic layer by hardening and setting the concrete, placing at least one cover layer comprised of asphalt placed while in a pasty state over the hardened basic layer, wherein the projecting portions of the support elements are embedded in and covered by the at least one cover layer, wherein the projecting portions provide protection for the cover layer against being displaced relative to the hardened basic layer when the road structure is exposed to loads during use.

13. The reinforced road structure as claimed in claim 11, wherein the support elements are made of iron or steel.

14. The reinforced road structure as claimed in claim 12, wherein the support elements are made of iron or steel.

Description

(1) The invention will now be described in connection with preferable embodiments thereof, in which reference will be made to the accompanying drawings. In the drawing:

(2) FIG. 1 shows a preferred embodiment of the road structure according to the invention in half ready state in a stepped section;

(3) FIG. 2 shows an enlarged detail similar to FIG. 1;

(4) FIG. 3 shows the enlarged cross sectional profile of a preferred embodiment of the support elements 3;

(5) FIG. 4 shows an alternative design of the support elements 3; and

(6) FIG. 5 shows the enlarged cross sectional view of the road structure.

(7) FIG. 1 shows the simplified stepped sectional view of the first embodiment of the road structure according to the invention in which at the bottom a solid basic layer 1 is arranged made of concrete. Below the basic layer 1 the ground is prepared for instance by compaction or with a different way or there can be a coarser grained concrete. The basic layer 1 has a design which can take and resist taking static and dynamic loads typically present at the road under construction, and the basic layer 1 has preferably a planar or slightly bowed upper surface which is preferred for leading water away and for its much cheaper manufacture as if it was an articulated structure. The basic layer 1 is preferably strengthened by a steel reinforcement which need not be indicated separately as it is not required for understanding the present invention.

(8) When the road is constructed, an asphalt cover layer 2 is provided on the top of the basic layer 1 by moulding. The asphalt layer 2 comprises as shown in the sectional view of FIG. 5 gravel with small pieces of different size and bitumen that fills the gaps between the pieces. In FIG. 1 the cover layer 2 has been shown in a partially removed state for the sake of illustrating the structure prior to the placement of the cover layer 2.

(9) Before the setting of the basic layer 1 support elements 3 are positioned from above which have special shape and layout as illustrated in FIG. 1 in such a way that the support elements 3 extend out from the upper surface of the basic layer 1 in a predetermined height normal to the surface, whereas the support elements 3 are at the same time sunken in a predetermined depth also in the basic layer 1. The support elements 3 are made preferably but not necessarily from iron, steel, or they can be made from a material designed to take the expected load. This task can also be taken by an appropriately chosen plastic material.

(10) FIG. 2 shows the design of a preferred embodiment of the support elements 3 in an enlarged view, in which the support elements 3 have the shape of stripes formed of half hexagons positioned normal to the surface and arranged opposite to each other and they are connected to each other at their contacting surface areas by means of bolts, rivets or by welding, whereby they constitute a closed arrangement of stable closed polygons e.g. form hexagonal grids that extend out of the surface to a predetermined height. This design is preferred because the closed polygons are interconnected with force fitting attachments, whereby they can resist forces coming from any direction that act on the cover layer 2 mould later thereon, whereby they prevent any displacement of the asphalt.

(11) In FIG. 1 it is illustrated schematically that the support elements 3 comprise respective openings made close to the height of the upper surface of the basic layer 1 which have been cut out of the material of the support elements 3 and bent outwardly relative to the original plane of the stripes (which plane is now vertical) to form tabs 4 that provide increased horizontal surfaces that prevent the support element 3 from being immersed in the material of the basic layer 1 when it is still in pasty state. The presence of the tabs 4 and the associated opening is also preferred because in this way in spite of the presence of the support elements 3 there will be a free flow of water through the openings of the support elements 3, and when the cover layer 2 is mould bitumen can flow in the openings causing a further stabilizing effect for the cover layer 2.

(12) The enlarged detail of FIG. 3 shows that in a preferred embodiment the stripes constituting the support elements 3 have an upper rim 5 with rounded and increased cross section i.e. the stripes do not have sharp edges but upper surfaces with an increased thickness. Such a design is preferable from the point of view of minimizing the hazard of accidents and following the setting of the lower basic layer 1 that fixes the lower portion of the support elements 3 this upper rim 5 makes it possible that prior to the placement of the cover layer 2 vehicles can move on their surface without the danger of their tires being cut by the sharp upper edges of the support elements 3. It is also preferred if the support elements 3 have a symmetric cross section i.e. provided with a similarly wide lower rim 5 as it is shown in FIG. 3 which reinforces their sit in the basic layer 1.

(13) FIG. 4 shows stripes 6 (or straps) which constitute the support elements 3 positioned in a spaced arrangement to illustrate that the formation of a closed structure defining holes is not an indispensable condition because the stripes 6 with their meandering lines can be sufficiently stable after the setting of the basic layer 1 in which their lower parts are inserted. In case of roads designed for lower load such an open design can also provide the required stability. If needed, the support elements 3 can also be made as stripes without having the widened rims 5 positioned normal to their plane surfaces in the basic layer 1.

(14) Reference is made now to FIG. 5 showing the cross section of the road after it has been finished. As described earlier following the setting of the basic layer 1 with the support elements 3 previously inserted therein, the cover layer 2 will be positioned from above by moulding in a soft, pasty state. The height of the projection of the support elements 3 above the basic layer 1 is not critical, whereas it is preferred if this height is at least as high as the half of the average size of the stone pieces 7 that constitute the gravel in the cover layer 1 so that the walls of the support elements 3 can provide sufficient resistance against the pressure of these pieces 7. The depth in which the support elements 3 should be inserted in the basic layer 1 can be determined only in the knowledge of the required loadability, but it is also preferred if the depth is at least the half of the average size of the gravel pieces in the basic layer 1. FIG. 5 shows the support elements 3 with different projecting heights. In any given actual embodiment only a single projecting height is chosen.

(15) From the examples shown it can be understood there are several ways for supporting the cover layer 2 made of asphalt, and of these possibilities the choice should be made according to the local conditions at the particular site, to the budget limitations or to other conditions. The essence lies only in that the support elements 3 inserted in and bound to the basic layer 1 stabilize the asphalt cover layer 2 and prevent it from getting displaced even under the simultaneous effect of the previously mentioned three types of load.