The invention deals with a road pavement module, especially road light re-bar board to assemble a temporary road on site or manoeuvre yard for heavy equipment on the miry area or to arrange a goods yard for barrels and other materials and to do works with heavy equipment on a peat bog as well.

There is a road reinforced concrete board equipped with lifting eyes to carry it with use of all terrain crane known from Polish description of the utility pattern Ru-45516.

In the Polish description of P-296577 application, elements of the possible to dismantle road pavement that overlap in the vertical cross section at all parallel joints are known; the vertical centre lines of the joints cross sloping sections of them exactly in the middle of the elements' thickness.

Due to the Polish description of P-376158 application, the road reinforced concrete board of one convex and one concave sides is known. There is an arc bent ledge between the circular sector's shaped edges of the convex side. The edges of the concave side are also circular sector's shaped and there is a groove of arc-wise surface between them. The groove's radius of curvature in the cross section is larger than the ledge's radius of curvature.

The aim of the invention is to design a road board that would be light and crack-proof and easy to assemble by hand, especially in case if no crane is at disposal.

The essence of the invention is that there is at least one open-work layer of mechanically arranged rods between two external surfaces of the board and joints are located on the external surfaces of the open-work layer. The rods in the joints on the external surfaces of the open-work layer are rigidly fixed, preferably by welding. The joints on the external surfaces of the open-work layer produce vertexes of a plane figure, preferably equilateral triangle.

The rods with joints are the edges of an open-work solid, preferably with the side of the equilateral triangle and/or quadrilateral. The joints that are the upper vertexes of the open-work solids of a tetrahedron shape are, in the upper located layer, the vertexes of the planar figure base for the open-work solids, preferably of a tetrahedron shape.

The open-work layers are fixed in the joints and the rods on the external surface of one open-work layer belongs at the same time to another open-work layer. The rods connected with joints are the edges of the open-work solid, preferably the cube or the octahedron or the decahedron of the equilateral triangle side. The open-work, mutually fixed layers, have different spatial structure, preferably achievable by partition and/or multiplication of the distances between the joints of the basic open-work layer. The external surface of at least one open-work layer is equipped with network, preferably of re- bar rods. There is a protective layer, preferably of perforated sheet and/or reinforced material, fixed with the external surface of at least one open-work layer.

The light open-work structure and the ease to assemble are the virtue of the invention.

The object of the invention is presented through examples of fabrication on the drawing that shows the road board as a whole and construction details as follows: Fig. 1 shows the detail of the tetrahedron solid assembled of rods determining the solid's edges.

Fig. 2 shows the detail of the cube assembled of rods determining the solid's edges. Fig. 3 shows the detail of the board assembled of two cubs of the common edge, the cubes being constructed with re-bar rods determining the edges in the two-layer board. Fig. 4 shows the magnified detail of the double-layer board containing two octahedron solids connected with the common edge.

Fig. 5 shows the magnified detail of the three-layer board, the rod connection joints of which determine the decahedron composed of equilateral triangles. Fig. 6 shows the rectangle board's projection onto the work surface. Fig. 7 shows the trapezium shaped board's projection onto the work surface. Fig. 8 shows the single-layer rectangle board's up-slant view. Fig. 9 shows the double-layer rectangle board's up-slant view.

Fig. 10 shows projection onto the road and yard work pavements assembled with the boards invented.

There are parts of the two-layer board models' shown in photographs: the up-slant view to the front of the board, the lower open-work layer having been made of dark rods and the upper one of light rods is shown in photo 1 ; the board's structure in two positions from one side is shown in photos 2 and 3. There is at least one open-work layer 1_of rods H between two external surfaces of the board, the rods being assembled mechanically, with joint X on the external surfaces of the open-work layer 1. In the joints X on the external surfaces of the open-work layer Λ_ the rods 11_are fixed rigidly, preferably with weld. Mutually fixed joints X on the external surfaces of the open-work layer 1 compose vertexes of the planar figure Δ _p, preferably the figure being an equilateral triangle. Fixed rods H with joints X are the edges of the openwork solid Δ, preferably with the side wall of the equilateral triangle and/or regular tetrahedron. The joints X in the upper vertexes of the open-work solids Δ_of the tetrahedron shape are the basic vertexes for the upper located open-work layer 2, the base being a planar figure Δ _p of the open work solids Δ preferably shaped as the tetrahedron Δ». The open-work layers 1 and 2 are mutually fixed in the joints X and the rods H on the external surface of one open-work layer i are at the same time the rods H of the external surface of the succeeding open-work layer 2. The fixed with joints X rods H are the edges of the open-work solid Δ the one can be shaped as cube Δ ₆ or octahedron Δ ₈ or dodecahedron Δ ₁₂ with the side of equilateral triangle. The mutually fixed open-work layers land 2 are of different spatial structure, preferably achievable by partition and/or multiplication of the distance a_between the joints X of the i basic open-work layer's structure. The external surface of at least one open-work layer 1_, 2 is equipped with network, preferably of rods 3 and/or of plastic. There is the protective layer 4 , preferably of perforated sheet and/or plastic of the reinforced inside structure, fixed with at least one of the 1, 2 open-work layers.

The closer explanation of the invention will now be given through examples of the open-work board assembly. Example I

The one-layer board has the square section rods H applied on the external surfaces and the rods intersect each other at an angle of 60° in each joint X. The mutually fixed joints X on the external surfaces of the open-work layer 1 compose vertexes of the planar figure Δ _p of equilateral triangle's shape. Three re-bar rods H, of a tension member's 12 shape, are fixed with every joint X with weld; the distance between the joints X is a and the angle between them is 120°. The tension members 12 fixed with adjoining joints X of one external surface are mutually connected symmetrically to the straight line that runs through the joints X. The edges of tetrahedrons A ₄ the upper vertexes of which are fixed with the joints H of a square section belonging to the next surface of the external surface of the one-layer board are composed by this way. A single-layer rectangular solid is made through multiplication of the re-bar's H and rods' 12 fixings within the rectangular outline. The tetrahedrons A ₄ , the joints X will be vertexes for, can be inscribed between the joints

Example Il

The one-layer board of a trapezium shape is made by the same way as the one in the Example I is, but in the contour of the isosceles trapezium. This shape's board makes it possible to assemble a road turn due to the invention. Example III

The external surface of the upper open-work layer l_of the two-layer board is made of re-bar rods U of the circular section. In addition, a network of thin re-bar rods 3 is made to reduce clearance between the joints X on the external surface. The reason is that the board is to be used on a peat bog to assemble the road for trucks carrying the peat dug up. The tension members Λ2 of length of the double distance a in between the joints X are prepared for a double-layer board. In the middle of their length the tension members Λ2 are fixed with weld to produce joints between the two layers 1 and 2. The tension members 12 fixed in the adjoining joints X of the surface of the upper open-work layer 2 are mutually connected by the rods H which are re-bar of circular section intersecting each other at an angle of 60°. Example IV

The external surface of the lower layer 1 of the double-layer board is made of re-bar rods H of the circular section that cross at the right angle. Four tension members 12 of length equal to the double distance between the joints X are fixed with every joint X. In the middle of their length the tension members 12 are fixed by welding which produces the joints X between the two layers 1 and 2. The tension members 12 fixed in the adjoining joints X of the surface of the upper open-work layer 2 are mutually connected by the rods H which are re-bar of circular section intersecting each other at the right angle. Octahedrons A ₈ can be inscribed in between the joints X, the joints X being vertexes for them. Example V

The external surface of the upper open-work layer 2 of the double-layer board is shielded with a protective layer 4 fixed with the joints X- the conveyor's belt of internal structure reinforced with re-bar being applied to it. The protective layer 4_protects in this case the rods H and 3 from damage that can be resulted from use of metal crawler chains of heavy equipment.

As it's been proven by operating testing of the boards, even on the elastic and soaked in water peat bog, the road assembled with the boards due to the invention had made it possible for trucks to carry output from the peat bog; the manoeuvre yard's pavement assembled with these boards had made heavy excavating equipment's traffic possible. After paving the boards on the peat bog and next applying a load with equipment, water had been squeezed out from peat above the board's surface to flow down back during longer use and the board remained uncovered on the elastic peat subsoil.

The boards invented, when paved at the exit from site, make it also easy cleaning the muddy truck wheels which is recommended before entrance to the public road system.

The. boards invented make it possible to pave the emergency road lane for planes, especially when a heavy transport aircraft has been landed out of concrete airstrip and there appears the need to pull it back to the strengthened concrete lane. The boards invented are particularly useful for fast assembly of the airstrip in military airfield or for light STOL (Short-Take-Off-And-Landing) aircraft of Cesna type for instance.

The ease to carry the light road boards, to pave them without necessity of possesing heavy rigging equipment and the ease to dismantle the temporary road after use indicate a wide range of application for the boards according to the invention.

While specific embodiments of the invention have been shown and described in detail to illustrate the inventive principles, it will be understood that the invention may be embodied otherwise without departing from such principles.