WO2018143808A1

WO2018143808A1 - Drainage blocks for dikes or urban settings

Info

Publication number: WO2018143808A1
Application number: PCT/NL2018/050074
Authority: WO
Inventors: Aroen MUGHAL; Hans Hill
Original assignee: Hill Innovations B.V.
Priority date: 2017-02-03
Filing date: 2018-02-02
Publication date: 2018-08-09
Also published as: BR112019016075A2; EP3577278A1; EP3577278B1; CN110520573A; DK3577278T3; JP2020506318A; NL2018297B1; DE202018006645U1; JP7146780B2; ES2856255T3; US20200378071A1

Abstract

A drainage block for dikes or urban settings and for use as a road pavement is provided with drainage and water buffering properties. The drainage blocks may be used in urban areas as pavement, or fundament or substructure underneath a street layer with porous / water passing pavement stones or clinkers with drainage and water buffering properties. The drainage blocks comprise four lateral faces, a base, and a single stem connecting the slab and the base, which stem has a cross-sectional area that is smaller than the cross-sectional areas of the slab and the base, thereby forming a water buffering space between the slab and the base; and wherein each of the four lateral faces of the slab comprises a single spacing projection.

Description

Drainage blocks for dikes or urban settings

Field of the invention

The present invention relates to drainage blocks, and in particular to drainage blocks for use in urban settings. Further, the present invention also relates to a drainage block for use in dikes.

Background art

A drainage block is known from publication US2012/0255624A1 , which discloses a drainage body comprising a base unit and a top unit. The base unit and the top unit are connected via frustoconic or frustopyramidal spacers. However, such drainage blocks are not suitable for use as pavement in an urban setting, as the top unit is formed as a hollow mesh containing many openings, which openings pose a hazard for pedestrians and cyclists and other users of a pavement in an urban setting. Further, partly due to said openings, such blocks do not meet government regulations for pavements. Summary of the invention

The present invention seeks to provide a drainage block for dikes as a road pavement with drainage and water buffering properties. The present invention also seeks to provide drainage blocks that can be used in urban areas as pavement with drainage and water buffering properties.

According to an embodiment of the invention, a drainage block is provided for use on dikes or in urban settings comprising four lateral faces, a base, and a single stem connecting the slab and the base, which stem has a cross-sectional area that is smaller than the smallest or minimum cross-sectional areas of the slab and the base, thereby forming a water buffering space between the slab and the base; and wherein each of the four lateral faces of the slab comprises a single spacing projection. The terms smallest and minimum are used interchangeably herein. Cross- sectional areas as referred herein refer to areas contained in a horizontal plane(s) perpendicular to a central longtudinal axis of the block. A central longitudinal axis refers herein to a central axis along the longest dimension of the block.

The spacing projections may be configured in any number of ways, for example, a single spacing projection may comprise multiple subprojections. Preferably the spacing projection has a surface that lies on a plane that is parallel to a plane along the surface of the lateral face, so that when two blocks are arranged adjacent to each other, the single spacing projection of one lateral face of the slab of the first block is in contact with the single spacing projection of one lateral face of the slab of the second block. The result is that a slab drainage opening is formed between the two slabs of the two blocks blocks, on either side of the contacting spacing projections. Such draining gaps on either side of the spacing projections have a substantially longitudinal cross- section. The hollow space between the slab and the base is intended for receiving surface water and buffering water by slowly releasing it into the ground or for redirecting the received surface water. By surface water it is meant herein any fluid resulting or coming from rainfall or waves from bodies of water (whether natural or manmade).

In an exemplary embodiment, the drainage block may have a height between 20 cm to 60 cm. The water buffering capacity of the drainage block as described above may range from 0,10 m³/m² (or 100 liter/m²) for the 20 cm block, to 0,42 m³/m² (or 420 liter/m²) for the 60 com block. Each of these dimensions, and the water buffering capacity, may be smaller or greater, without departing from the scope of the invention. The hollow spaces between the drainage blocks are large enough to be inspected and cleaned by commonly used sewer inspecting and cleaning devices.

In an embodiment, the single spacing projection on each lateral face of the slab forms or defines two recesses on the lateral face, wherein a plane defined along the surface of the two recesses is parallel to a plane defined along the surface of the spacing projection, so that when four blocks are connnected together in a substantially square arrangement, a slab drainage opening with a substantially cross-shaped cross-section is formed between said four blocks. The recesses are formed by those portions of the lateral surface which do not contain a spacing projection. The dimensions of the drainage space (or gaps) is such that pedestrian and cycling traffic may safely transit atop the slabs when the block is used as pavement in urban settings.

In an embodiment, the spacing projections have a depth or thickness with respect to the recesses (or portions of the lateral faces which do not contain the spacing projections). The depth or thickness is such that, when blocks are adjoined adjacent each other, drainage gaps are formed which are of a size sufficient to drain a required volume within a certain time span. In an exemplary embodiment, the spacing projections have a depth or width of 4 mm and the drainage gap formed by two adjoining spacing projections is 8 mm. This advantageously allows for drainage to occur, while keeping the size of the spacing such that pedestrian and cycling traffic (and other types of traffic) may transit safely atop the slabs without hazard.

In an embodiment, the base has four lateral faces and each of the four lateral faces of the base comprises a single spacing projection, so that when two blocks are arranged adjacent to each other, the single spacing projection of one lateral face of the base of the first block is in contact with the single spacing projection of one lateral face of the base of the second block; thereby forming a base drainage opening on either side of the contacting spacing projections. The single spacing projection on each lateral face of the base defines two recesses on the lateral face, wherein a plane defined along the surface of the two recesses is parallel to a plane defined along the surface of the spacing projection, so that when four blocks are connnected together in a substantially square arrangement, a drainage opening with a substantially cross-shaped cross-section is formed between said four blocks.

The spacing projections preferably have a length equal to the length of the lateral faces.

The length of a spacing projection may be, for example, 25% or 50% of the length of the lateral face.

In an embodiment, the spacing projections of the slab are aligned with the spacing projections of the base. That is, the surface of the spacing projections of the slab and the surface of the spacing projections of the base are contained in the same plane. This facilitates drainage of the fluid, as the draining openings formed by the slabs are aligned with the drainage openings formed by the bases.

In an alternative embodiment, the spacing projections on the slab do not coincide or are not aligned with the spacing projections on the base. For example, the spacing projections may be intercalated with respect to the stems. This is advantageous for an application of the block in which it would be desirable to increase the buffering function or capacity, as the fluid needs to flow through a greater distance from the slab area in order to reach the drainage gaps formed by the bases.

In an embodiment, the stem has a circular cross-section (defined as contained in a horizontal plane(s) perpendicular to its central longitudinal axis) throughout its extension, and its maximum length is greater towards the slab and towards the base, thereby defining a curved surface between the slab and the base. The cross-sectional maximum length in the case of a stem with a circular cross-section is equivalent to the diameter. This advantageously allows for a smoother flow of the fluid passing through the block, as the smooth curve shape of the buffering space reduces turbulence. The curved shape also benefits from the surface tension effect so as to guide the fluid downwards from the slab draining spaces to the base draining spaces.

In an embodiment, the stem has an oval cross-section (defined as contained in a horizontal plane(s) perpendicular to its central longitudinal axis) throughout its extension, which cross-section has a maximum length, and wherein said maximum length is greater towards the slab and towards the base, thereby defining a curved surface between the slab and the base. An oval cross-section advantageously provides greater and sufficient support, particularly if the block is manufactured as a half block, as it provides more body in the stem.

In an embodiment, the stem has a rectangular cross-section (defined as contained in a horizontal plane(s) perpendicular to its central longitudinal axis) throughout its extension, which cross-section has a maximum length, and wherein said maximum length is greater towards the slab and towards the base, thereby defining a curved surface between the slab and the base. A rectangular-shaped cross-section advantageously allows for a block or half-block that is easier to manufacture as well as being more cost-effective.

In an embodiment, the cross-sectional diameter or the cross-sectional maximum length of the stem is greatest towards the slab. This allows the drainage block to accommodate more tension due to traffic loads when used in urban areas. Additionally or alternatively, the cross-section of the stem is smaller towards the base (as small as possible), in order to provide space for inspection and/or cleaning devices.

In an embodiment, the block is monolithical. That is, the entire block is manufactured as a monolithical element. This may be achieved by using a mold. A monolithical or integrally-formed block is advantageous as it reduces assembly time on an area or terrain to be covered or paved with the blocks. By monolithic it is meant herein a block that is formed of a single piece of material.

In another embodiment, the slab and the base have the same height. The height of the slab and base may be, for example, 40 cm or 45 cm. The slab and base may have a different thickness, for example, the slab may have a height of 45 cm, while the base may have a height of 40 cm. Such an embodiment would be particularly suited to urban settings, which are not subject to waves and wave forces, as the resistance provided by the block need not be so high. A block characterized by having a base and a slab of substantially equal weight is sufficiently stable in an urban setting.

In an embodiment, the base has a greater height than the slab. This advantageously provides for a block with increased resistance, particularly suited for use on dikes or any other areas which may be exposed to waves and wave forces. It is also advantageous when more resistance to displacement is needed in view of inclination or slope of the terrain.

In an embodiment, the base has a peripheral groove which divides the base into an upper base section and a lower base section. This groove advantageously increases the fixation of the blocks, when filled with small rubble stone. Such an embodiment would be particularly suited for use in dikes. The subsections are not fully separate from each other.

In a further embodiment, the upper base section (as formed by the peripheral groove) has a spacing projection, which may have the same height as the upper subsection. This advantageously facilitates assembly of the blocks in an area to be covered as it functions as an indication of alignment between the blocks, and further assists the spacing created by the spacing projections provided on the slabs, in particular if the upper base spacing projection(s) has the same depth as the spacing projection(s) of the slab.

According to another aspect of the invention, a strip drainage block is provided comprising a slab, a base, and a plurality of stems connecting said slab and base, wherein each of the plurality of stems has a cross-sectional area that is smaller than the smallest or minimum cross-sectional areas of the slab and the base, wherein the slab and the base each comprise two longitudinal faces, each comprising a plurality of spacing projections. Such a block is advantageous as the larger dimensions facilitate faster assembly or pavement of an area. The plurality of stems comprise any number of stems, for example, it may comprise at least two stems. Alternatively, the plurality of stems may comprise at least three stems. Preferably, the plurality of stems may comprise at least four to five stems. This advantageously reduces the time required for assembly of a drainage block pavement. In particular, a block (or half block) with five, or at least five, stems is stronger and is easier to manufacture.

In an embodiment, each of the plurality of stems of the strip drainage block has a circular cross-section (cross-section herein is defined as contained in a horizontal plane(s) perpendicular to its central longitudinal axis) throughout its extension, and the diameter is greater towards the base and towards the slab, thereby defining a curved surface between the slab and the base. This advantageously allows for a smoother flow of the fluid passing through the block, as the smooth curve shape of the buffering space reduces turbulence. The curved shape also benefits from the surface tension effect so as to guide the fluid downwards from the slab draining spaces to the base draining spaces.

In an alternative embodiment, each of the plurality of stems of the strip drainage block has an oval cross-section (cross-section herein defined as contained in a horizontal plane(s) perpendicular to its central longitudinal axis) throughout its extension, the oval cross-section having a maximum length, and wherein said maximum length is greater towards the base and towards the slab, thereby defining a curved surface between the slab and the base. A curved shape directs the loads, which are applied on the slab, in an effective way. This is because the pressures on the block are distributed in a way that as much as material can be saved, while maintaining material in the areas where the pressures are higher.

In a further embodiment, each of the plurality of stems has a rectangular cross-section (cross-section herein is defined as contained in a horizontal plane(s) perpendicular to its central longitudinal axis) throughout its extension, the rectangular cross-section having a maximum length, and wherein the maximum length is greater towards the base and towards the slab, thereby defining a curved surface between the slab and the base. A curved shape directs the loads, which are applied on the slab, in an effective way. This is because the pressures on the block are distributed in a way that as much as material can be saved, while maintaining material in the areas where the pressures are higher.

In a further embodiment, two of the plurality of stems are outer stems defining two flat, lateral ends of the block, which outer stems comprise a semi-circular, a semi-oval, or a half- rectangle cross-section (depending on the type of strip drainage block as disclosed above as defined by the cross-sectional area of the plurality of stems). By semi-circular and semi-oval cross- section it is meant herein a half-circle cross-section and a half-oval cross-section. By half-rectangle cross-section it is meant herein that the outer stem cross-sectional area is substantially half of the cross-section area of a stem that is not an outer stem.

If the block is provided in two parts (i.e. two half blocks), the corresponding outer stem will have a wedge-shaped cross-section (corresponding to half of a half-circle), or a quarter oval cross- section, or a quarter-rectangle cross-section, depending on the type of strip drainage block (as defined by the cross-sectional area of the plurality of stems). The lateral ends of a drainage block comprising external stems are characterized by flat surfaces which provide a surface for connecting an adjoining a strip drainage block. The lateral ends are preferably flat so that a more stable connection is achieved between two adjoining strip drainage blocks.

In an embodiment, the plurality of of spacing projections define recesses along the slab and the base. The term recesses is used herein to refer to those portions of the slab and base which do not contain a spacing projection, that is, those portions are recessed with respect to the spacing projections. Each of the plurality of spacing projections may have a length that is equal to, or smaller than, the diameter or maximum length of the smallest cross-section of each of the plurality of stems. Alternatively or additionally, each of the plurality of spacing projections may have a length that is defined as a ratio of the length of the longitudinal faces of base and slab, for example, each spacing projection may have a length that is 15% of the length of the longitudinal faces of the slab or base. Each of the plurality of spacing projections may have a depth (or thickness) of, for example, 3 mm, with respect to said recesses on the base and slab. The depth or thickness may be larger or smaller depending on the desired size of the drainge gap or spacing. A larger gap increases the drainage rate.

In an embodiment, each of the plurality of spacing projections is aligned with one of the plurality of stems. Alternatively, the spacing projections may be arranged so that they are not aligned with the stems. For example, they may be intercalated with the stems. The number of spacing projections may relate to the number of stems, for example there are preferably two spacing projections per stem in a strip drainage block provided as whole, and one spacing projection per stem in a strip drainage block provided as a half block. This provides adequate ability to space adjoining blocks.

In an embodiment, the drainage blocks according to the invention are made of concrete, including geopolymer concrete. Manufacturing the blocks (and half-blocks) out of concrete makes for a stronger block, and in particular makes for a block that can be used as pavement without the need for a top or cover layer (such as drainage sand or other such top layers). When the drainage blocks are used as a fundament/substructure they can be covered with a much less thick top or cover layer than would be necessary in the case of the known blocks, because of the strength of the block according to the invention. Other materials for making the blocks and half-blocks may also be used, such as baked clay or plastics.

In a preferable embodiment, the drainage blocks are comprised of two half blocks each comprising a half slab, a half stem, and a half base, and one flat surface, and wherein the half blocks are arranged adjacent to each other along their respective flat surfaces, so that the half blocks are symmetrical with respect to a central longitudinal plane of the drainage block. In this manner, one whole drainage block is formed by joining two half drainage blocks. By joining it is meant herein two half blocks being arranged next to each other, along their flat surfaces, either with or without an adhesive such as cement. Preferably, the half blocks are adjoined without the use of adhesives.

According to a further aspect of the invention, a method for manufacturing drainage blocks according to the above description is provided, comprising the step of forming the drainage block using a mold. This facilitates manufacturing of the blocks. A mold would thus be provided conforming to the physical and dimensional aspects described herein, which mold is filled with the material of choice for forming the drainage block.

In a further embodiment, the drainage block is formed by adjoining (as defined above) two half blocks, the half blocks being formed by using molds.

Short description of drawings

The present invention will be discussed in more detail below, with reference to the attached drawings, in which

Figs. 1A-1 C show several views of a drainage block according to an aspect of the invention. Fig. 2 shows an arrangement of a plurality of drainage blocks according to an aspect of the invention.

Figs. 3A-3C show several views of a drainage block according to another aspect of the invention.

Fig. 4 shows an arrangement of a plurality of drainage blocks according to the invention. Figs. 5A-5B show several views of a strip drainage block according an aspect of the invention.

Figs. 6A-6B show several views of a strip drainage block according to the invention. Figs. 7A-7B show several views of a strip drainage block according to another aspect of the invention.

Figs. 8A-8B show several views of a strip drainage block according to another aspect of the invention.

Description of embodiments

Figs. 1 A shows an axonometric view of a drainage block 100 according to an embodiment of the invention, comprising a slab 102, a single stem 104, and a base 106. Fig. 1 B shows a side view of the drainage block 100. Fig. 1 C shows another side view with a cross-section ll-ll. A cross- section of the stem. The block 100 has a height H1 . The slab 102 has a height H2, and the base 106 has a height H3. In the depicted embodiment, the slab and the base have the same height (that is, H2 = H3). The stem 104 has a semi-oval cross section characterized by a length D and a width R, with D being greater than R. The semi-oval cross-section increases from a substantially central area towards both the base 106 and the slab 102, but the increase is greater towards the slab 102.

Fig. 2 shows an arrangement 200 of a plurality of blocks 100. As can be seen in the figure, adjoining four blocks 100 in a substantially square arrangement results in the creation of a substantially cross-shaped drainage gap or spacing 202. The blocks are adjoined such that the spacing projections of one block are adjacent to the spacing projections of a further block. In this case, the spacing projections of both the base and the slab of one block adjoin respective spacing projections of the base and the slab of a further block.

Fig. 3A shows an axonometric view of a block 300 for use in a dike. The block 300 comprises a slab 302, a single stem 304, and a base 306. The base 306 is divided into an upper base section 306a and a lower base section 306b by a peripheral groove 308. The upper base section 306a has a spacing projection 310 on two of its four faces.

Fig. 3B shows a side view of the block 300. Fig. 3C shows another side view with cross- section along a plane ll-ll. The block 300 has a spacing projection 310 on two faces of the four faces of the upper base section 306a. The block 300 has a height H5 and the slab has a height H6. The base has a height H7, the upper base section has a height H7a, and the lower base section has a height H7b. The stem has a height H8. The peripheral groove has a height H9 and a depth D. The stem 304 is symmetrical with respect to a central horizontal plane, increasing in size equally from a central area towards the slab 302 and towards the base 306.

Fig. 4 shows an arrangement of a plurality of blocks 300. As can be seen in the figure, adjoining four blocks 300 in a substantially square arrangement results in the creation of a substantially cross-shaped drainage gap or spacing 402 formed by the spacing projections of the slabs. The blocks are adjoined such that the spacing projections of one block are adjacent to the spacing projections of a further block. In this case, the base of each block only has two spacing projections 310, arranged on opposing faces of the upper base sections 306a.

Fig. 5A shows a strip drainage half block 500 according to an embodiment of the invention. The block 500 comprises four spaced stems 506 arranged between a slab 502 and a base 504. The base and the slab have spacing projections 510 and 512, respectively, which are aligned with the stems 506. The slab has two longitudinal faces 502 and the base has two longitudinal faces 504. Fig. 5B shows the other side of the block 500. The block 500 has a height HS1 and a length LS1 .

Fig. 6A shows a strip drainage half block 600 with a slab 606 and a base 608, each with two longitudinal faces, 614 and 616, respectively. A plurality of stems 603 are arranged between the slab 606 and the base 608. In this embodiment, the strip block has two outer stems 604a, b, and has two flat, lateral ends 602. The slab 606 has spacing projections 612 and the base 608 has spacing projections 610, along one of their respective longitudinal faces. Fig. 6B shows the other side of the strip half block 600.

Fig. 7A shows a strip drainage block 700, with a base 706 and a slab 702. A plurality of stems 704 are arranged between the slab 702 and the base 706. The slab has two longitudinal faces 712 and the base has two longitudinal faces 714. A plurality of spacing projections 710 and 708 are arranged along said longitudinal faces. Fig. 7B shows the other side of the block 700.

Fig. 8A shows a strip drainage block 800, with a base 806 and a slab 802. A total of five stems 804 are arranged between the slab 802 and the base 806. The slab has two longitudinal faces 812 and the base has two longitudinal faces 814. A plurality of spacing projections 810 and 808 are arranged along said longitudinal faces. Fig. 8B shows the other side of the block 800.

The present invention has been described above with reference to a number of exemplary embodiments as shown in the drawings. Modifications and alternative implementations of some parts or elements are possible, and are included in the scope of protection as defined in the appended claims.

Claims

Drainage block for use as pavement or as substructure on dikes or urban spaces comprising: a slab having four lateral faces for connecting to other blocks;

a base;

and a single stem connecting the slab and the base, which stem has a cross-sectional area that is smaller than the smallest cross-sectional areas of the slab and the base, thereby forming a hollow space between the slab and the base; and

wherein each of the four lateral faces of the slab comprises a single spacing projection, so that when two blocks are arranged adjacent to each other, the single spacing projection of one lateral face of the slab of the first block is in contact with the single spacing projection of one lateral face of the slab of the second block; thereby forming a slab drainage opening between the two slabs on either side of the contacting spacing projections.

2. Drainage block according to claim 1 , wherein the single spacing projection on each lateral face of the slab defines two recesses on the lateral face, wherein a plane defined along the surface of the two recesses is parallel to a plane defined along the surface of the spacing projection, so that when four blocks are connected together in a substantially square arrangement, a slab drainage opening with a substantially cross-shaped cross-section is formed between said four blocks.

3. Drainage block according to any of the preceding claims, wherein the base has four lateral faces and each of the four lateral faces of the base comprises a single spacing projection, so that when two blocks are arranged adjacent to each other, the single spacing projection of one lateral face of the base of the first block is in contact with the single spacing projection of one lateral face of the base of the second block; thereby forming a base drainage opening between the two bases of the two blocks on either side of the contacting spacing projections, and the single spacing projection on each lateral face of the base defines two recesses on the lateral face, wherein a plane defined along the surface of the two recesses is parallel to a plane defined along the surface of the spacing projection, so that when four blocks are connected together in a substantially square arrangement, a drainage opening with a substantially cross-shaped cross-section is formed between said four blocks.

4. Drainage block according to claim 3, wherein the spacing projections of the slab are aligned with the spacing projections of the base.

Drainage block according to claim 3, wherein the spacing projections on the slab are not aligned with the spacing projections on the base.

Drainage block according to any of the preceding claims, wherein the stem has a circular cross-section throughout its extension which cross-section has a maximum length, and wherein said maximum length is greater towards the slab and towards the base, thereby defining a curved surface between the slab and the base.

Drainage block according to any of claims 1 -5, wherein the stem has an oval cross-section throughout its extension, which cross-section has a maximum length, and wherein said maximum length is greater towards the slab and towards the base, thereby defining a curved surface between the slab and the base.

Drainage block according to any of claims 1 -5, wherein the stem has a rectangular cross- section throughout its extension, which cross-section has a maximum length, and wherein said maximum length is greater towards the slab and towards the base, thereby defining a curved surface between the slab and the base.

9. Drainage block according to any of claims 6-8, wherein the cross-sectional maximum length is greatest towards the slab.

10. Drainage block according to any of the preceding claims, wherein the block is monolithical.

1 1 . Drainage block according to any of the preceding claims, wherein the slab and base have the same height.

12. Drainage block according to any of claims 1 -1 1 , wherein the base has a greater height than the slab.

13. Drainage block according to claim 13, wherein the base has a peripheral groove which divides the base into an upper base section and a lower base section.

14. Drainage block according to of claim 13, wherein the upper base section has four lateral faces and has a spacing projection on two of the four lateral faces.

15. Strip drainage block for use as pavement or as substructure on dikes or urban spaces, comprising a slab, a base, and a plurality of stems connecting said slab and base, wherein each of the plurality of stems has a cross-sectional area that is smaller than the smallest cross-sectional areas of the slab and the base, wherein the slab and the base each comprise two longitudinal faces, each comprising a plurality of spacing projections.

16. Strip drainage block according to claim 15, wherein each of the plurality of stems has a circular cross-section throughout its extension, the circular cross-section having a maximum length, and wherein the maximum length is greater towards the base and towards the slab, thereby defining a curved surface between the slab and the base.

17. Strip drainage block according to claim 15, wherein each of the plurality of stems has an oval cross-section throughout its extension, the oval cross-section having a maximum length, and wherein said maximum length is greater towards the base and towards the slab, thereby defining a curved surface between the slab and the base.

18. Strip drainage block according to claim 15, wherein each of the plurality of stems has a rectangular cross-section throughout its extension, the rectangular cross-section having a maximum length, and wherein the maximum length is greater towards the base and towards the slab, thereby defining a curved surface between the slab and the base.

19. Strip drainage block according to any of claims 15-18, wherein the plurality of stems comprise at least five stems.

20. Strip drainage block according to claim 15, wherein two of the plurality of stems are outer stems and define two flat, lateral ends of the block.

21 . Strip drainage block according to any of claims 15-20, wherein the plurality of spacing projections define recesses along the slab and the base, and wherein each of the plurality of spacing projections has a length that is equal to, or smaller than, a maximum length of the smallest cross-section of each of the plurality of stems.

22. Strip drainage block according to any of claims 15-21 , wherein the each of the plurality of spacing projections is aligned with one of the plurality of stems.

23. Drainage block according to any of the preceding claims, wherein the block is made of concrete.

24. Drainage block according to any of the preceding claims, wherein the block is comprised of two half blocks each comprising a half slab, a half stem, and a half base, and one flat surface, and wherein the half blocks are arranged adjacent to each other along their respective flat surfaces, so that the half blocks are symmetrical with respect to a central longitudinal plane of the drainage block.

25. Method for manufacturing a drainage block according to any of the preceding claims, comprising forming the drainage block using a mold.

26. Method of claim 25, wherein the drainage block is formed by adjoining two half blocks, the half blocks being formed by using molds.