CA1049825A - Composite paving structures and units and processes for making them - Google Patents

Abstract

ABSTRACT OF THE DISCLOSURE

A composite paving is formed by laying units each having elongate rupture zones along which it is breakable into individual stones and being formed with recesses in opposed sides thereof, and linking stones separately engageable in the recesses of adjacent pairs of the laying units. Each linking stone being the same facial shape and size as one of the laying stones or a fraction or multiple thereof, and the rupture zones are so disposed that the individual interlocking stones form a herringbone pattern wherein a shorter side of each stone lies adjacent part of a longer side of another of the individual stones.

Description

The invention relates to composite paving constructed primarily of units (herein generally termed "laying units") placed or laid in position.
Paved surfaces are known that are constructed by laying relatively large slabs or laying units on a prepared sub-structure.
Such laying units are provided with elongate rupture zones along which each unit is breakable into a plurality of individual stones.
It is an object of the present invention to provide a novel and improved composite paving using such laying units.
According to the invention, there is provided a composite paving for traffic areas or other graded or inclined ground surfaces, comprising laying units and linking stones, each said laying unit being a relatively large unitary slab transportable as a unit by being gripped mechanically at opposite lateral sides thereof, - the sl~ab having preformed therein elongated rupture i.. . -;~ 20 zones sub-dividing it into adjoined stones and along ~ ~ - which after being laid it is breakable under stress into .. j- .
laterally interengaged individual stones, each said laying unit having in opposed lateral sides thereof at least one recess, the recesses in the lateral sides each ex-tending the full height of the respective laying unit and substantially corresponding in facial shape and size to one said individual stone or a fraction or multiple thereof, each said unit when laid having at least one lateral side thereof lying at and along, and having therein at least ! 30 one said recess which confronts a respective recess in, ;- , , , - ~ . . : . ~ :.
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a lateral side of at least one other said unit, each set of the c~nfronting recesses being filled by at least one said linking stone inserted thereinto and which in-terconnects the respective juxtaposed laying units by ;-~
extending across the gap between them, each said linking stone having the same height as the laying unit and having substantially the facial shape and size of one said individual stone or of a fraction or multiple thereof, and the rupture zones being so disposed that the in-dividual interlocking stones form a herringbone pattern wherein a shorter side of each stone lies adjacent part of a longer side of another of said individual stones.
; The present invention further provides a com-: posite paving, comprising a plurality of laying units formed with recesses in opposed sides thereof, a plurality of linking stones separately engageable in the recesses of adjacent pairs of the laying units, each of the laying units having elongate rupture zones along which it is breakable into in-, dividual stones, and the linking stone being the same facial -shape and size as one of the stones or a fraction or multiple thereof, and the rupture zones being so disposed that the individual interlocking stones form a herringbone pattern wherein a shorter side of each stone lies adjacent part of a longer side of another of the individual stones.
The interlocking of the individual stones may be achieved e.g. solely by the herringbone pattern and sand or the like between the individual stones or may in addition be assisted e.g. by the provision of projections and withdrawn portions and/or protuberances and recessed parts on the stones as described in greater detail hereinafter.
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In order that the invention may be clearly understood and readily carried into effect several embodiments thereof will now be described by way of example with reference to the accom-panying drawings, in which like or corresponding parts are desig-nated by like reference numerals and in which:
Figure 1 shows in plan a portion of a composite structure having laying units provided with recesses at two opposite sides;
Figure 2 shows the composite structure according to Figure 1 in cross-section taken along the line II-II of that figure, Figure 3 lS a plan view of a portion of a composite structure wherein the laying units are formed with recesses at opposite sides and are laid as a cross-bond structure, Figure 4 shows in plan view a portion of a composite structure wherein the laying units have recesses in all - sides of their periphery and are laid as a herringbone bond, Figure 5 shows a plan view of a portion of a composite structure wherein the laying units each have recesses along their entire periphery and are subdivided by gredetermined , ,:

rupture zones into elements arranged in parquet pattern, Figure 6is a plan view of a portion of a composite structure wherein the laying units each have recesses in their entire periphery and are laid offset relative to each other, Figure 7 shows in plan a portion of a composite struc-ture similar to that according to figure 6, having an alter-native form of the predetermined rupture zones and sup-plementing stones, Figure 8 shows in plan a portion of a composite struc-ture also similar to that according to Figure 6, with an alternative design of the predetermined rupture zones and supplementing stones, Figure 9 shows a plan view of a portion of a composite structure wherein the laying unit is formed along its entire periphery with recesses which, with respect to two axes, are arranged in mirror-image fashion relative to each other, Figure 10 is a plan view of a portion of a composite structure of substantially square laying units into each of which a supplementing stone is inserted at all four sides for connecting adjacent laying units with each other, . : ~
Figure 11 is a cross-section through a laying unit taken ~.
along a line XI - XI of Figure 10, Figure 12 shows a plan view of a portion of a composite structure of substantially rectangular laying units, in the transverse sides of each of which supplementing stones are -inserted for connecting adjacent laying units with each other;
Figure 13 is a cross-section partly through a jointing gap between two adjacent laying units taken along the line XIII - XIII of Figure 12, Figure 14 shows in plan a portion of a composite struc-ture comprising substantially rectangular laying units sub-divided by predetermined rupture zones into shaped stone elements arranged in herringbone fashion and at the longi-tudinal and transverse sides of which supplementing stones are inserted for connecting adjacent laying units with each other;
Figure 15 is a cross-section through a jointing gap between two adjacent laying units taken along the lines XV - XV of Figure 14;
Figure 16 shows an underneath plan view of a portion of the composite structure according to Figure 14 in the region where the supplementing stone is inserted into the adjacent laying units, the illustration being drawn to a larger scale; -Figure 17 shows an underneath plan view of a portion of a composite structure similar to that shown in Figure 14, drawn to a larger scale;
Figure 18 shows in perspective several known stone shapes which may be adopted as the shape of the elements and of the supplementing stones;
Figure 19 shows a section through a laying unit wherein a free dummy jointing gap has been cut normal to the longi-tudinal direction thereof;
Figure 20 is a longitudinal section taken along the line XX - XX in Figure 19, through a predetermined rupture zone and a free dummy jointing gap the height or level of which varies lengthwise thereof;
Figures 21 to 24 are longitudinal sections similar to that of Figure 20, through further similar embodiments;
. 30 Figure 25 shows a longitudinal section through a pre-determined rupture zone and a free dummy jointing gap, an insert made from elongated material particles being provided ~ 5 -'' ,~,~

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", ' ' ~ ' . ' '' ' , at a predetermined height or level of the laying unit, Figure 26 is a longitudinal sec-tion through a predeter-mined rupture zone of a laying unit in the stage of formation of the dummy gap and into which an insert is pressed by a - shaped element to produce the dummy gap' and Figure 27 shows a longitudinal section through a pre-determined rupture zone and a free dummy gap of a laying unit, wherein a net-like insert is provided.
The composite structure shown in Figure 1 is assembled from laying units 2 and linking or supplementing stones 30. The laying units 2 have an elongated, substantially rectangular shape having rectilinear longitudinal edges 4. A network of simulated or dummy jointing gaps 8, 10 extends over the upper surface of each laying unit 2. The dummy jointing gaps 8 extend continuously parallel to the longitudinal edges 4 of the laying unit 2 and have regular spacing a relative to each other or relative to the longitudinal edges 4. The dummy jointing gaps 10 extend perpen-dicular to the dummy jointing gaps 8 and are so interrupted, at alternate rows constituted by the dummy jointing gaps 8 and, at the edge, by the longitudinal edges 4, that the dummy jointing gaps 10 are offset by the amount a from row to row in the longi-tudinal direction. The dummy jointing gaps 10 also have regular spacing a relative to each other. Owing to the network of dummy jointing gaps 8, 10 there is formed on the upper side of the laying unit 2 a pattern of lndividual stones or rectangular elements 40 whic~
respectively of a length equal to 2a and of a width equal to a, and which constitute a pattern of so-called cross-bond composite structure. In the transverse direction, each laying unit is delimited by an edge 6 extending, at the corner of the laying unit 2, first of all for the length a at right angles to the longitudi-nal edge 4 of the laying unit 2 and then for the length a towards the interior of the laying unit 2, parallel to the longitudinal edge 4, then once again for the length a at right angles to the longitudinal edge 4, then for the length a in the outward direc-tion away from the interior of the laying unit 2, parallel to the longitudinal edge 4 and then continuing repeatedly in this manner. The transverse edge 6 of the laying unit 2 thus pre-cisely continues the pattern of the dummy jointing gaps 8,10 at the edge of the laying unit 2 and provides square recesses 20 of lateral length a and open towards the exterior of the laying `unit.
The spacing of the recesses 20 or the spacing relative to the longitudinal edge 4 of the laying unit 2 again is a in each case.
The individual laying units 2 as seen in the longitu-dinal direction are separated from each other by a jointing gap 12. Further laying units 2 follow in the transverse direction ~
having corresponding jointing gaps 12. The recesses 20 are ar- ~ -range~ symmetrically with respect to a transverse axis of the laying unit 2 and the individual laying units - without relative displacement in the transverse direction - are laid against each other, so that the longitudinal edges 4 of adjacent laying units 2 are in line. The recesses 20 formed in adjacent laying units 2 face each other, the gaps thereby formed in the composite structure are filled by rectangular supplementing stones 30 which connect the adjacent laying units 2 together in the transverse direction so as to resist thrust. Due to the dummy jointing gaps 8,10, the edges 4, 6 and the inserted supplementing stones 30, a continuous uniform cross-bond pattern is formed on the surface of the composite structure.
The depth of the dummy jointing gaps 8,10 is approximate-ly 1/3 of the thickness of the laying unit 2 and the remainingthickness constitutes in each case a predetermined rupture zone 60. Depending on the material of which the laying unit 2 is made, , ~,,'~

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, 1049~Z5 some other depth of the dummy jointing gaps 8, lO and corres-pondingly of the predetermined rupture zones 60 may be more ad-vantageous; it is merely necessary to ensure on the one hand that the laying unit 2 has sufficient strength for storage, transport and laying and on the other hand that the predeter-mined rupture zone 60 can be caused to rupture for example by jarring with a percussion device, or by stress due to traffic or thermal forces. The upper edges of the dummy jointing gaps 8,10 and also the peripheral edges 4,6 are finished with small ; 10 chambers 14.
The composite structure is laid on a prepared and levelled base 50, consisting for example of sand. The jointing gaps 12 between adjacent laying units 2, and those between lay-ing units 2 and the supplementing stones 30, are filled prefer-ably from above with sand, for example with sand having a grain ~ size ranging between 0 and 3.
; The dummy jointing gaps 8,10 in the embodiment being described have a cross-section in the shape of a narrow open rectangle extending downwardly from the upper side of the laying unit 2. Instead of this however it would also be possible to provide dummy jointing gaps on the underside of the laying unit ~ 2 or dummy jointing gaps both on the upper and on lower side -, which may additionally be laterally offset relative to each other to for~ inclined predetermined rupture zones 60 in the laying unit 2. For ease of manufacture of the laying units 2 it may be advantageous to make the lateral walls of the dummy jointing gaps 8,10 converge slightly inwardly.
The laying units 2 may be made of any desired harden-able materials which meet the requirements in regard to sultabi-~ 30 lity for moulding, cost and strength. Preferably they are made ; of concrete.

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, ~049825 The size of the laying units 2 is approximately 1 m2.
mey could of course be made smaller or larger. The larger the laying unit 2, the more economical is the laying of the compo-site structure, in the upward direction however the size of the laying unit 2 is limited by the dimensions of the production machine for manufacturing it and by the carrying capacity of the laying devices.
The further embodiment of a composite structure shown in Figure 3 comprises laying units 2 of square shape (disregar-ding the recesses) and wherein two recesses 20 are formed at each of the longitudinal sides. The laying units 2 are subdivided by dummy jointing gaps 8 in the longitudinal direction and by dummy jointing gaps 10 in the transverse direction, into elements 40 which as described in detail with reference to Figure 1 cons-titute a cross-bond pattern and are attached together through the agency of predetermined rupture zones 60. m e rectangular ele-ments 40 are arranged in this embodiment with their longer dimen-sions extending in the transverse direction of the laying unit 2.
The recesses 20 are T-shaped, the cross bar of the T
(as it were) constituting the open side of the recess. me re-cesses 20 are designed to form part of the cross-bond pattern of the dummy jointing gaps 8,10 and occupy the surface area of two elements 40.
- The individual laying units 2 are arranged offset rela-tive to each other by a half-length, in other words, they are also laid in cross-bond pattern. The supplementing stones 30 inserted into the recesses 20 which face each other at the lon-gitudinal sides 4 of the laying units 2 without being offset fonm a horizontal composite bond in the longitudinal dlrection ~ -~
of the laying units 2, whereas a horizontal composite bond is provided in the transverse direction of the laying units 2 due ~ ' , .

to the mutual offsetting of the laying units 2.
The supplementing stones 30 have the shape of a cross of length 4a and width 3a. They may additionally (as indicated by broken lines) be subdivided by shallow dummy jointing gaps to provide a visual impression corresponding to the shape of the elements 40 or they may also be pre-notched to such an extent by means of adequately deep dummy jointing gaps that they rupture along the predetermined rupture zones provided thereby, like the laying units 2. In this manner the pattern of the elements 40 may be continued over the entire composite structure also in cases where the supplementing stones 30 are of an area equal to that of a plurality of elements 40. of course, instead of the cruci-form supplementing stones 30, it will be possible also to employ four supplementing stones each of the size of the elements 40.
; In the case of the embodiment of a composite structure (as shown in Figure 4) laying units 2 of substantially rectangu-lar shape are provided of which the length is twice the width.
As in the embodiment according to Figure 1, the laying unit 2 is subdivided by dummy jointing gaps 8 in the longitudinal direc-tion and dummy jointing gaps 10 in the transverse direction into rectangular elements 40 of length 2a and width a attached to each other by predetermined rupture zones 60. In the centre of the transverse sides 6, each laying unit 2 has a recess 20, and , the longitudinal sides 4 each-have two recesses 20 respectively arranged in the centre of each longitudinal side half. Whereas the recesses 20 at the transverse sidés of the laying unit 2 are produced by omitting the half elements 40 which otherwise would be present as part of the cross-bond pattern, resulting in square recesses of a lateral length a, in order to form the recesses 20 at the longitudinal sides 4 of the laying unit 2, the uniform cross-bond pattern is slightly varied, inasmuch as one half has been omitted of the rectangular elements 40 of the - , ~

cross-bond pattern.
In this embodiment the laying units 2 are laid as a herringbone composite structure and abut along jointing gaps 12.
In addition to the bonding effect resulting from the herringbone mode of laying the laying units 2, the inserted supplementing stones 30 provide a well sub-divided bonding effect preventing relative displacement of the laying units 2 along the jointing gaps 12.
Figure 5 shows a further embodiment of a composite structure of substantially square contour, i.e. disregarding the recesses 20 at the periphery of the laying units 2. Dummy join-ting gaps 8 and 10 disposed parallel to this imaginary square contour extend throughout the upper side of the laying unit 2.
The dummy jointing gaps 8 and 10 are spaced from each other or from the base of the recesses 20 by a distance 2a thereby form-ing a square checkerboard pattern on the upper side of the lay-ing unit 2. Each of these squares is then subdivided either by further dummy jointing gaps 9 extending parallel to the dummy jointing gaps 8 or by further dummy jointing gaps 11 extending ~ -parallel to the dummy jointing gaps 10, into two rectangular elements 40, so that neighbouring squares are subdivided in dif-ferent directions.
The edges 4 and 6 of the periphery of the laying units 2 have rectangular recesses 20 of length 2a and width a of which the length extends in the main direction of the particular edge 4 or 6 and can be regarded as providing for the continuation of the pattern by addition of further elements 40 in the longitudi-nal direction of the particular edge 4 or 6 to the above-describ-ed checker board pattern. In this way the upper side of the laying unit 2 ia subdivided by a network of dummy jointing gaps 8,10 in so-called parquet pattern, and the recesses 20 are in each particular instance continuations of the parquet pattern , . , -. .

with omitted elements 40.
Adjacent laying units 20 are so disposed in side-by-side relationship spaced apart by the jointing gap 12 that cor-responding recesses face each other without any offsetting.
At the corners of the laying units 2 (as shown on the left-hand side in Figure 5) larger recesses having length 3a and width a are formed by superpositioning the recesses of two edges.
Whereas onLy two rectangular supplementing stones 30 having the shape of the elements 40 are inserted into the recesses 20 in 10 the central zone of the edges 4,6, at the corners it is necessa-ry to insert six supplementing stones 30. It will be appreciated that the pattern of the elements 40 is completely continuous over the entire composite structure due to the supplementing stones 30.
However, it is also possible, instead of supplementing stones 30 having the size of the elements 40, to insert correspondingly larger supplementing stones, for example square ones of edge length 2a, into the facing recesses 20.
Figure 5 on the right-hand side shows how by appropriate design of the laying unit 2 and using a further element 40, the formation of large corner recesses can be avoided.
The hitherto-de:cribed embodiments all relate to rec-tangular elements 40 having a length 2a and a width a. It is obvious that the elements could have other length/width ratios.
In the case of the embodiment shown in Figure 6, each laying unit 2 of the composite structure is made up from rectan-gular elements 40 arranged in herringbone pattern of length 2a and width-a joined together by predetermined rupture zones 60 constituted by dummy jointing gaps 8 and 10. The contour of the laying unit 2 can be thought of as having been brought into be-ing by cutting from a large-area herringbone pattern a rectangle having a length of twelve element widths and a width of seven element widths and that then the elements cut-through at the , - ,,,~ ~ .

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104~8Z5 periphery of the rectangle are extracted from the laying unit 2 in order to form the recesses 20. The portion of the herring-bone pattern is to be so cut out that there is formed in each case at the edges 6 in the transverse direction of the laying unit a recess in the centre of the edge 6. Then there are form-ed in each instance at the outer longitudinal edges 4 of the lay-ing unit 2 three recesses 20 offset relative to each other at opposite longitudinal edges 4 of the laying unit 2 by the value of one element width. Placed adjoining a laying unit 2 in the longitudinal direction along jointing gaps 12 are further laying units (without lateral off-setting), whereas in the transverse direction relative to the laying unit 2 the adjacent laying unit 2 is placed laterally offset by the value of three element widths in order that the recesses 20 formed in the adjacent laying units 2 may be disposed opposite each other. I'he recesses 20 facing each other are again filled with supplementing stones 30 of ele-ment size so that the composite structure seen as a whole ex-hibits a continuous and uniform herringbone pattern.

The laying unit 2 may also be employed in larger format, for example of double width, so that a plurality of recesses is formed also in the transverse edge 6.
In the case of all the embodiments hitherto described, the individual elements 40 of the laying unit 2 and also the con-necting stones 30 are all of rectangular shape. Additional advantages however follow from a design of the contours of the recesses 20 corresponding to the supplementing stones 30, with projections and withdrawn portions since thereby it becomes possible to achieve traction-resisting engagement of adjacent laying units. The shape of the recesses and of the supplementing stones may, furthermore, be repeated in the shape of the indivi-dual elements 40. These projections and withdrawn portions may 10498~5 be provided by plane or curved delimiting spaces in periodic, axis-symmetrical or central-symmetrical arrangement, or in any other desired arrangement. Figures 7 and 8 show by way of ex-ample two embodiments taken from the large possible number of variations, as a portion of the laying units 2 according to Figure 6.
In the case of the embodiment shown in Figure 7, the elements 40 have a shape predetermined by the dummy jointing gaps 8 and 10 of zig-zag outline. The recesses 20 and the sup-plementing stones 30 also have the same shape. Elements form-ed with projections and withdrawn portions provide particularly good horizontal bonding of the elements 40 to each other.
The contour of the elements 40, the recesses 20 and the supplementing stones 30, in the case of the embodiment shown in Figure 8, is in the form of sinusoidal lines which replace the rectilinear lateral delimitations according to Figure 6.
Also in the case of this embodiment a traction-resisting connec-tion of the two adjacent laying units 2 is achieved and especial-ly effective horizontal bonding of the elements 40 to each other.
The composite structure of the embodiment shown in Figure 9 may be thought of as having been derived from the lay-ing unit 2 shown in Figure 6 by adding to its longitudinal side a further row of elements 40 of like width as an element width.
The shape of the elements 40, the recesses 20 and the supplemen- -~
ting stones 30 corresponds to the embodiment shown in Figure 7.
In addition to the opposite lateral edges 6 of the laying unit 2, in the case of this embodiment the opposite lateral edges 4 of the laying unit are also designed to be mirror-images of each other. The composite structure now con-sists of laying units 2 which are not offset relative to each other in any direction and of connecting stones 30 inserted into ; recesses 20 located opposite each other (as shown). However . ",~

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also with this shape of laying units 2 it is possible to provide a composite structure having laying units 2 that are laterally offset relative to each other in the longitudinal direction.
With this embodiment of the composite structure, how-ever, there is formed at a corner A of each laying unit 2 a spe-cially shaped recess 21 which is twice the size of the other re-cesses 20 of the relevant laying unit 2 and in each particular instance is equivalent to two half supplementing stones 30 in extent. However, this does not produce any disadvantage for the composite structure' but it will be expedient to ensure that on stacking the laying unit 2 on edge the edge A is positioned up-permost.
Whereas in the case of the embodiments hitherto des-cribed the supplementing stones contribute to the horizontal bonding effect of the laying units relative to each other, there ~
will now be described embodiments in which the supplementing ' stones and the recesses have vertical bonding faces effective in one direction.
In the case of the embodiment shown in Figures 10 and 11, the contours of the laying units 2 of the composite structure have been produced from a square contour. Each laying unit 2 is sub-divided by first dummy jointing gaps 8, 10 on the upper side of the laying unit 2 into 21 elements 40 which are squares as seen in plan. The said shaped stone elements are joined togeth-er via predetermined rupture zones 60 extending obliquely rela-tive to the upper side of the laying unit 2, the predetermined rupture zone 60 being formed by the first dummy jointing gaps 8, 10 designed in the form of open recesses on the upper side of , the laying unit 2 and by second dummy jointing gaps 8',10', a-gain having the shape of open recesses, arranged on the under-Jide of the laying unit 2 with lateral spacing from the first dummy jointing gaps 8,10. The first dummy jointing gaps 8,10 ~-~ and the second dummy jointing gaps 8',101 each extend parallel .

. : ' ' to the edges 4,6 of the laying unit 2 which basically form a square.
In the centre of each side of the laying unit 2, there is arranged, instead of an element 40, a recess 20 having in its upper half a contour 26 in the shape of an open sided square.
Each laying unit 2 is provided at its periphery with ~-protuberances 3 and recessed parts 5. The protuberances 3 have the shape of a protruding step half the height of the laying unit, the length thereof being that of two element lengths.
They each extend from a recess 20 towards the right to a loca-tion a short distance before the corner of the particular laying unit 2, proceeding from the recesses 20 towards the left, the recessed parts 5 extend in the form of a withdrawn step again having half the height of the laying unit 2. At the inner con-tour 26 of the recesses 20, there are again protuberances 22 and 24 which, in the case of this embodiment, occupy half the height of the laying unit 2. With this arrangement, the protuberances 24 are each arranged at that side of the recess 20 which is ad-jacent the protuberance 3 at the contour 4 of the laying unit 2.
The protuberances 24 are of such a length that they merge into the recesses 6. The protuberances 22 at the opposite side of the recess 20 are somewhat shorter than would correspond to the recess, so that the particular recessed part 5 at the contour of ., :
the laying unit 2 continues undisturbed as far as the recess 20.
The protuberances or recessed parts 3, 5, 22 and 24 are delimited -at their upper side in each instance by horizontal faces 7 and 23. It should be specially emphasised that these spaces may also be so designed that they are inclined relative to the hori-zontal, preferably being inclined relative to the centre of the rece~s 20. i~; -The individual laying units 2 are so laid that the recesses 20 of adjacent laying units 2 face each other. With f/)~ :
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this arrangement there remains in the horizontal direction, be-tween the individual laying units 2 a jointing gap 12 for taking up thermal expansion of the composite structure which may for ex-ample be filled with sand or poured with bitumen. Inserted from above into the facing recesses 20 of adjacent laying units 2 are supplementing stones 30 which are rectangular as seen in plan view. The supplementing stones 30 are of two-zone construction, the lower zone corresponding to the recessed part 32 having half the height of the supplementing stone, extending in the longitu-dinal direction of the supplementing stones 30. The transition portion from the lower zone to the upper zone of the supplement-ing stone 30 is constituted by horizontal faces 33.
On placing the laying units 2 one against the other, the protuberances 3 engage into the particular opposite recessed parts 5, thereby achieving a vertical bonding effect of the lay-ing units 2 relative to each other. At the location of the in-serted supplementing stones 3 a horizontal bonding effect is pro-duced between the laying units 2 and, additionally, a vertical bonding effect which is effective in one direction. The hori-zontal faces 7, 23 and 33 for vertical engagement may also be formed as inclined faces. Additionally, if vertical tolerances are provided for, jointing gaps (filled for example with sand) can be provided in the vertical direction at these engagement faces.
The composite structure of which a portion is shown in Figures 12 and 13 has laying units 2 of substantially rectangu-lar shape. These are sub-divided by first dummy jointing gaps 8,10 on the upper side of the laying unit 2 into elements 40 which as seen in plan view are double-T-shaped. The surface-~hape, defined by the first dummy-iointing gaps 8,10 of the sha-ped stone elements 40 is known per se. It is produced if, in , ~049825 the case of a rectangular shaped stone, there are formed recesses 44 of which the inner delimitation extends parallel to the origin-al longitudinal sides of the stone and the lateral delimitations extend outwardly in chambered manner. In this way a recess 44 is produced having the shape of an open trapezium and into which the head-piece 42, not associated with the recesses, of two adjacent shaped stones can be partially inserted, Shaped stones of such configuration can therefore be laid one against the other, longi-tudinally and offset by half a stone length in each case.
The individual elements 40 of each laying unit 2 are jointed together via predetermined rupture zones 60 extending in-clined with respect to the upper side of the laying unit 2. To form such predetermined rupture zones 60, there are provided in addition to the first dummy jointing gaps 8,10, second dummy joint-ing gaps 8', 10' on the underside of the laying unit 2 as indicat-ed in Figure 12 by broken lines. The second dummy jointing gaps 8' are arranged, over the greater portion of their length, with lateral spacing relative to the first dummy jointing gaps 8, this being especiaLly simply achieved in the longitudinal direction of the laying unit 2 by rectilinear second dummy jointing gaps 8' extending respectively alternately to one side and to the other side of the first dummy jointing gaps 8. In the transverse direc-tion of the laying unit 2, for example the second dummy jointing gaps 10' are arranged alternately to one side and to the other side of the first dummy jointing gaps 10.
At each transverse side of the laying unit 2, every alter-nate half element 40 is omitted to form recesses 20. The head-pieces 42 of the elements 40 which have been left are in each case provided with recessed parts 5 located underneath, whereas in the case of the supplementing stones there are arranged, in the zone of the recesses 40, protuberances 34 located underneath, so that the full rectangular format is restored in an under-layer of the Aii . .

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supplementing stone 30. The recessed parts S and the protuberan- -ces 34 are connected, through the agency of obliquely-extending vertical engagement faces 7 and 35, to the particular contours visible from the upper side. The supplementing stones 30 are in each case inserted from below into two facing recesses 20 of the adjacent laying units 2. On laying the composite structure, first of all with the laying unit 2 in a raised position the supplement-ing stones 30 are inserted from below, as to one half in each case, into a recess 20, and then the laying unit 2 is set down on the prepared bed. On placing the next adjacent laying unit 2, further supplementing stones 30 merely require to be inserted from below at one transverse side of the laying unit 2, whereas the recesses 20 at the other transverse side of the laying unit are slid-on from above over the supplementing stones 30 already laid with the adjacent laying unit 2. There are jointing gaps 12 be-tween adjacent laying units 2, and between the laying,units and the inserted supplementing stones 30.
Also at the longitudinal sides of the laying units 2, provision may be made for vertical bonding effect between adjacent laying units 2. For example, the recesses 44 formed in the ele-ments 40 located at the edge may be provided in a manner similar to that employed with the supplementing stones 30, with protuber-ances 34 occupying a portion of the height of the recess 44. Cor-responding recessed parts in a lower zone of the head-pieces 42 ~ of the adjacent laying unit 2 may engage over the projections 32 -~ at this location. By means of flat webs or lands half-way up the recess 44 and corresponding slots in the head-pieces 42, it is also possible to achieve a vertical engagement effective in two directions between adjacent laying units 2.
The composite structure of which part is shown in Figures 14, 15 and 16 has laying units 2 of substantially rectangular shape. The upper side of each laying unit 2 is divided, by first :~04982S
dummy jointing gaps, into a pattern of rectangular elements 40 ar-ranged in the manner of a herringbone bonded pattern.
The second dummy jointing gaps 8', lO' associated with the first dummy jointing gaps 8, lO for providing inclined pre-determined rupture zones 60, on the underside of the laying unit 2, are zig-zag shaped, the teeth on both sides of the associated first dummy jointing gap 8', lO' projecting for an equal distance, as indicated by broken lines in a corner of Figure 14.
Each laying unit 2 has the length of eight element widths and the width of seven element widths. At all locations where, in the case of a corresponding rectangu~ar portion cut from a herringbone bond pattern elements 40 would be intersected, -square recesses 20 are formed by omitting appropriate element halves. Along the entire outer periphery of each laying unit 2, - saw-tooth-like protuberances or projections 16 and recessed parts or withdrawn portions 18 are provided in a lower zone of the lay-ing unit 2. The transition to the vertical contour faces l9 of the upper layer is provided by inclined toothed-engagement faces 15.
As shown in the drawing at two facing recesses 20, the contour of the recesses 20 is also in each case provided with two recessed parts 28 serving simultaneously as withdrawn portions and having the shape of the recessed parts 18. It follows from the fact that these recessed parts 28 are also formed only in a lower zone of the laying unit 2 that the supplementing stones 30 can, during laying, be inserted only from below into two facing recessed of adjacent laying units 2. A corresponding insertion méthod during laying has already been described above.
As supplementing stone 30 a rectangular stone is used having at its longitudinal sides, in a lower zone, protuberances or projections 36 and also recessed parts or withdrawn portions 38, and at its transverse side only recessed parts or withdrawn '' ' ' .
.

-~-'` 1049825 ,rtions 38. The shape of these protuberances 36 and recessed parts 38 corresponds again to the shape of the protuberances 16 and the recessed parts 18 at the periphery of the laying unit 2.
The recessed parts 38 in this arrangement are devoid of any func-tion in respect of the bonding effect.
The embodiment of the composite structure shown in Figure 17 is very similar to that shown in Figures 14 to 16. In the case of the present embodiment however the entire inner contour of the recess 20 is provided with protuberances 29 which also serve as projections and with recessed parts 28 which also serve as with-drawn portions, so that the inner contour of the recess 20 corres-;

ponds to the contour of the lower zone of the laying unit 2, theprotuberances 29 and recessed parts 28 being shaped to correspond to the protuberances 16 and the recessed parts 18. The inserted supplementing stone 30 on the other hand has only recessed parts 38 and can therefore be inserted from above into the facing recess 20 of the already placed laying unit 2. Instead of the protuber-ances 36 of the preceding embodiment, the contour of the supple-menting stone in the present case has vertical contour faces, the recessed parts 28 perform no function in respect of the bonding effect. The second dummy jointing gaps 8', 10' which are associat-ed with the first dummy jointing gaps 8,10 for providing inclined predetermined rupture zones 60 and which are disposed on the under-side of the laying unit 2, extend in undulating manner, the undu-latio~ being of like size on both sides of the associated first dummy jointing gap 8 or 10.
Figure 18 shows a selection of known shaped stones which can be used in connection with the invention as supplementing ; stones 30 or as indicative of the shape of the individual elements 40. In the case of a), there is shown a shaped stone having two plane end faces and two undulating longitudinal faces which are axis-symmetrical relative to each other. The shaped stone shown at b) has two opposite undulating end faces and two zig-zag-shaped . ",~;, .

longitudinal faces which are complementary and can be broughttogether by parallel displacement.
The shaped stone shown at c) is of substantially double-T-shape and has two straight end faces.
The shaped stone shown in d) has the shape of a distorted Z and is described more fully in German specification No. 960 359.
The interlocking stone shown under e) has two plane end faces: the longitudinal faces are adapted to be brought together by parallel displacement relative to each other and have the shape of a central undulation adjoining two lateral half-undulations.
The shaped stone shown under f) may be compared with the shape of a T having a curved recess in its upper central portion.
All the corner edges, with the exception of the lower corners at the horizontal limb of the T are cut off by relatively large 45 chambers. The shape of this shaped stone is described more fully in German specification No. 1 119 315.
The shaped stone shown at g) has equal flat covering surfaces, a base line enclosing the equivalent of a pair of ad-joining squares and side surfaces at the two pairs of vertically extending parallel stone sides, the side surfaces being disposed in zig-zag fashion about the base line and enclosing right angles , at the corners of the stone and their reversal lines being equi-distant from the base line and with like inclination to the base line forming equal angles therewith and in the middle of the long -sides being of twice the length as at the stone corners, so that all side surfaces in every direction are inclined at the like angle to the base line. This shaped stone is more fully describ-ed in German specification No. 1 658 570.
Figure 19 shows a section through a laying unit 2 having a free open dummy jointing gap 10 extending from the upper side 70 of the laying unit. The dummy gap 10 has a rectangular profile as seen in cross-section. The cross-section could be of any other .

;, ~, ' . ~ ' '' "`~ ' '' , desired profile, similarly, the corners may be bevelled or rounded.
After the laying unit 2 has been laid at the predeter-mined location it is ruptured into its individual elements 40, for example by vibration from an eccentric-weight percussion device or due to stressing by traffic or also due to thermal stressing of the surface slab. Because of the presence of the dummy gap 10, rupture takes place along a predetermined rupture zone 60 extending from the bottom 80 of the dummy gap 60 to the opposite underside 72 of the laying unit 2.
Figures 20 to 24 show several embodiments in which the height or level of the dummy gap 60 varies in different ways along the length thereof. Although, in all the figures a laying unit 2 is shown in which the dummy gap 10 extends from the upper side 70 into the interior of the laying unit 2, nevertheless - this feature of the invention can in like manner be applied to laying units 2 in which a dummy gap extends from the underside 72 of the laying unit 2 or in which dummy gaps 10 are provided ex-tending both from the upper side 70 and also from the underside 72. In the case of dummy gaps 10 being formed in both the upper side 70 and also in the underside 72, they may either be disposed vertically under each other, or they may be spaced laterally from each other whereby the predetermined rupture zone 60 forms an angle with the vertical.
- In the case of the example of embodiment shown in Figure 20, the bottom 80 of the dummy gap extends in undulating or cor-rugated configuration. This corrugated profile 80 may consist of a periodic succession of "undulations" of uniform height (as shown). The height and length of the "undulations" however may vary in regular or non-uniform manner if this would be of ad-vantage for particular fields of application.
In the further embodiment shown in Figure 21, the bottom , ~ ,.
,~
~.

~0498ZS

80 of the dummy gap 10 extends in the manner of regularly spaced serrations forming a zig-zag line. The height and spacing of these serrations can be selected within wide limits, depending on the intended purpose. Other non-uniform longitudinal profiles can readily be envisaged, in the case of this embodiment, a special characteristic resides in the formation of apices, ex-tending upwardly and downwardly at the bottom 80 of the dummy gap 10.
In the embodiment shown in Figure 22, the height of the dummy gap 10 extends, in places the entire height of the laying unit 2. Thereby, the predetermined rupture zone 60 is subdivided into a plurality of predetermined rupture sections 60'. The predetermined rupture sections 60' are equidistantly spaced from each other, in the example illustrated, but non-uniform spacings also are within the scope of the invention. In ; the case of the embodiment shown, the predetermined rupture sec-tions 60' have a rectangular longitudinal profile 80.
This longitudinal profile constituted by the bottom 80 of the dummy gap 10, of the individual predetermined rupture ;
sections 60' can be varied in many ways. Thus Figure 23 shows an embodiment wherein the longitudinal profiles are sections of an ellipse. The embodiment shown in Figure 24 has longitudinal profiles 80 comprising vertical sections and sections that are inclined in the longitudinal direction, so that in longitudinal : section the individual predetermined rupture zones 60' acquire the shape of a rectangle surmounted by a triangle.
The area occupied by the predetermined rupture zones 60 or the predetermined rupture sections 60' thereof (inlongitudinal section) is so dimensioned that the laying unit has a sufficient stability for laying but can with certainty be divided into in-dividual elements 40 by the methods described or similar methods.

-~ The ratio of the total longitudinal section area of the laying ~ - 24 -.,~
' ' ' ~ ' ' ' ''~ ' unit 2 to the area occupied by the predetermined rupture zones 60 or the predetermined rupture sections60 depends inter alia on the size of the laying unit 2, on the strength of the material employed, and also on the geometrical shaping of the bottom 80 of the dummy gap 10.
Laying units 2 in which the height of the dummy gaps 10 varies along their length have been described above in sche-matic form with reference to a laying unit 2 having a single dummy gap 10 and two elements 40. It is to be understood that laying units can be constructed in accordance with the principles described having a plurality of dummy gaps 10 and elements 40, and in particular also laying units formed with recesses 20 at the periphery for receiving supplementing stones 30.
Figure 25 shows a laying unit 2 having free open dummy jointing gaps 10 extending from the upper side 70 of the laying unit 2 and intersecting each other at right angles. From the bottom 80 of the dummy gaps 10 extend predetermined rupture zones 60 as far as the underside 72 of the laying unit 2. Approximate- :~
ly half-way up the predetermined rupture zones 60 an insert of elongatedmaterial particles 90 are provided, in the laying unit 2. In the case of the embodiment shown these are wire sections disposed with random orientation in the material of the laying unit 2. Moreover where greater demands are made on the reinforc-ing effect of the insert, the material particles 90 can have a preferred orientation imparted to them transversely to the direc-tion in which the predetermined rupture zones 60 extend. However, any material particles 90 disposed transversely of the predetermin-ed rupture zones 60 afford an anchoring connection of the elements 40 cohering by way of the predetermined rupture zones 60, thereby :
enhancing for example the resistance to breakage of the material o the laying unit 2 during transport or on laying. Additionnally, also after rupture of the predetermined rupture zones 60, improved -r~
. .- ..

. .

.
.

cohesion of the elements 40 is achieved.
To manufacture the laying unit 2 according to Figure 25, the procedure is for example first of all to introduce a lower material layer for the laying unit 2 into a mould, then to sprinkle the material particles 90 on to the introduced material layer from out of a container above the mould and then to introduce the remainder of the material for the laying unit 2 into the mould.
Figure 26 shows a laying unit 2 similar to the one de-scribed with reference to Figure 23. An insert comprising threads 92 disposed parallel to each other, for example nylon or other plastics threads, extends along the entire laying unit 2 and in particular along the individual predetermined rupture zones 60'.
The direction of these inserted threads 92 is preferably such that the two sides of the periphery of the laying unit 2 which are grasped on transport or on laying are connected with each other, thereby enhancing resistance to tensile stress in the direction in which maximum tensile stressing is to be expected.
To manufacture the laying unit 2 shown in Figure 26, the mode of procedure is first of all to introduce the entire material required for the laying unit 2 into a mould and then to draw the threads 92 off for example from an appropriate roller or beam, and to lay them on to the material introduced into the mould. Then a shaped element in the form of a recessing plate 98 is lowered from above which enters the material of the laying unit 2 and presses the threads, with its zone projecting furthest forwardly on to the bottom of the mould. The filaments 92, however, which are not engaged by these zones projecting furthest forwardly are not pressed as far as the bottom of the mould but curve up and consequently pass through the predetermined rupture zones 60' at a height located above the bottom of the mould.
It will be appreciated that a thin layer of material of the laying unit 2 can be present below the zones 99 projecting . ~ . .

furthest downwardly of the recessed plate 98. Such thin material layers are not to be excluded by the wording "dummy gap sections occupying the entire height of the laying unit".
The zones 99 projecting furthest downwardly of the recessing plate 98 are provided at their sides facing the pre-determined rupture zones 60' with underengagement projections 100 having, in longitudinal section through the recessing plate 98, an outwardly inclined upper edge. These underengagement pro-jections 100 serve for retaining the laying unit 2 in the mould frame after removal of the bottom of the mould. In plan view of the recessing plate 98 the underengagement projections are tri-angular in cross-section, and are formed on their upper side with an inclined cutting edge facing the particular predetermined rupture zones 60'. Then on extracting the recessing plate 98 the cutting edges displace the material of the laying unit 2 disposed above them, whereby predetermined rupture zones 60' are formed which are scored in their lateral marginal zones in the direction in which the recessing plate 98 is extracted from the mould.
Figure 27 shows a laying unit 2 similar to the one described with reference to Figure 20. Substantially half-way - up the predetermined rupture zone 60, the laying unit 2 has extending through it an insert in the form of a plaited or braid-ed or woven structure 94 made from steel wire or plastics strands.
This fabric is relatively wide-meshed and after introduction of a first material layer into a mould for the laying unit 2, the fabric can be wound off in especially simple manner from an ap-propriate supply roll and applied on the said first material layer, whereupon the remainder of the material for the laying unit 2 is introduced into the mould. Due to the wide mesh of the fabric, the two material layers readily bond to each other.
The fabric 94isa flexible three-dimensional structure affording , . , . ~ , -:

on the one hand the desired enhanced resistance to tensile stress of the material of the laying unit 2 but on the other hand not hindering rupture of the predetermined rupture zone 60, for example, after the processes described above. The strength of the fabric 94 can for example also be such that even when the predetermined rupture zones 60 have ruptured cohesion of the elements 40 is maintained.
Since, in the case of laying units for inclusion in such composite structures the individual elements first of all cohere by way of still unruptured predetermined rupture zones, -~ the laying units can be taken up as a single whole without use of lateral pressure, in particular mechanically and can be set down at the laying location. After the composite structure has been laid, rupture along the predetermined rupture zones is ini-tiated, for example by jarring with an eccentric-weight percus-sion device, or by stressing or loading due to traffic, or due to thermal stressing. With this arrangement, the roughness of the ruptured faces and also the sand swept into the jointing gaps, for example a sand having a maximum grain size corresponding to the width of the jointing gaps~ provide a certain degree of con-necting effect of the individual elements also after rupture.
Such predetermined rupture zones can extend either per- -pendicular to the surface of the laying unit or at an angle there-to. If predetermined rupture zones are provided extending in varying directions as seen in plan view of the laying unit, for example in zig-zag form or in undulating form, a horizontal con-nection is produced well able to transmit forces, in the case of predetermined rupture zones inclined at an angle to the surface of the laying unit, an especially effective vertical connection of the individual elements is achieved. Additionally, it is possible to combine the horizontal and vertical connecting effect.

~ - 28 _ .~ .

The composite structure when laid exhibits a uniform appearance, and that the structure is made up of an assembly of laying units and supplementing stones is, depending on the simi-larity of the jointing gap hardly recognizable or not recogniz-able at all if they are identical.
Since, in the case of a large-area composite structure, :
it is necessary to have a relatively large number of supplement-.. .

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.,' . ..... .
, . ~ . ,~. . .. . .

- 28a -. ,~
.
, - . , : . : , .

ing stones, it is preferred that all the supplementing stones should have the same shape. To cater for considerable variation of stresses in the composite structure in different directions, supplementing stones of appropriate shape, thickness and/or qua-lity, can be selected depending on the degree of stressing in the location concerned.
Such a pattern may for example be a cross~bond pattern or a parquet bond pattern, however, it is especially advantageous to select a herringbone pattern since this results in a horizon-tal bond of the elements relative to each other which resistshorizontal thrust in all directions. In the case of the herring-bone bond pattern, there are no continuous jointing gaps in any one direction, so that settlement or lateral displacement along gaps extending over a relatively large distance are prevented.
Similar considerations apply, in larger measure, to the arrangement of the laying units themselves relative to each other, since there are in fact genuine jointing gaps between them. In a further development of the invention the laying units are off-set relative to each other, being for example also themselves laid in the manner of a herringbone bond structure. However, there are also many other possibilities for arranging the laying units to be offset relative to each other, for example in brick-work bond structure, a cross-bond structure, or a so-called par-quet bond structure.
According to a further development of the invention, the recesses facing each other and the supplementing stone inser-ted in each particular instance have projections and withdrawn portions in the horizontal direction engaging at least partially one behind the other and connecting the adjacent laying units, transversely of the intermediate jointing gap, to be fast against tension. Such a mode of connecting the adjacent laying units with each other to be fast against tension is to be recommended 29 _ , , - ' . ', ~ ' '' ' ~:. ' in the case of considerable traffic loading due to heavy vehicles, covering of substrates of a difficult nature, for example such as tend to settle or yield, or covering inclined surfaces such as harbour embankments, or the like. The projections and withdrawn portions may each exhibit contours of rectilinear, trapezoidal, simusoidal or any other rectilinear or curvilinear shape. Espe-cially preferred is a contour of the recesses into which already known and commercially available stones, for example of simple double-T shape, can be inserted as supplementing stones, and also an axis-symmetrical or central-symmetrical design of the recesses.
The supplementing stones subjected to tensile stressing may, in the case of special requirements, also be provided with steel re-inforcement.
In simpler cases, recesses having the shape of an open rectangle may suffice, thereby providing a thrust-resisting connec-tion of the laying units in the direction of the intermediate jointing gap.
Especially if the composite structure has laying units each consisting of a plurality of elements cohering by way of predetermined rupture zones that are inclined relative to the sur-; face of the laying unit, and if furthermore the laying units are formed at their outer periphery with means for mutual vertical toothed engagement, vertical bonding of the laying units may be attempted in the regions of the inserted supplementing stones, so far as readily feasible. In further development of the invention, therefore, the facing recesses of the inserted supplementing stones have protuberances and recessed parts which at least par-tially engage over each other and so as to limit displacement of the particular supplementing stone relative to the adjacent lay-ing units at least in one vertical direction.
- It is possible so to design the interengaging protuber-ances and recessed parts, for example in the manner of tongue and .: : . ........ . - . , . - . :
', - .' ' ~ - .

groove connection, that displacement of the supplementing stone relative to the adjacent laying units is limited in both vertical directions. In this case however the supplementing stone must be pushed at least obliquely from the front into the recess thereby making laying of the entire composite structure more difficult.
Consequently, it is preferred so to design the protu-berances and recessed parts at the inner contour of the recesses and at the periphery of the supplementing stone either in such manner that the supplementing stone can be inserted from below in-to the facing recesses of the adjacent laying units or that the supplementing stone can be inserted from above. Which mode of design is to be preferred depends on the expected principal direc-tion of stressing of the composite structure. If for example it is to be expected that the greater degree of stressing will be applied from above, due to heavy wheel loads, provision will be made for insertion of the supplementing stone from above, If however a high degree of stressing of the composite structure from below is expected, for example due to reaction thrust, it may be ` more advantageous to insert the supplementing stone from below.
The terms "protuberance" and "recessed part" are herein ; - in general used to mean that at the relevant locations the contour - of the recess or of the supplementing stone does not extend verti-cally, but that in the vertical direction, as seen from above, material projecting over an imaginary vertical contour face is lo-cated opposite material removed from such a vertical contour face.
Similarly, the terms "projection" or "withdrawn portion" are here-in in general used to mean that at the relevant location the con-tour of the recess or of the supplementing stone does not extend along a vertical plane perpendicular to the open side of the re-` 30 cess, but that, as seen in the horizontal direction, material is provided which projects beyond the said imaginary vertical plane or material which has been removed relative to such a vertical "~

plane.
It is pointed out that the boundary or contour of the projections and withdrawn portions and also of the protuberances and withdrawn parts may have any desired rectilinear or curviline-ar configuration. In particular, a wedge bounded by a vertical face extending obliquely relative to the open side of the recess is considered to constitute a limit case of a projection or with-drawn portion, and a wedge bounded by an oblique face inclined relative to the surface of the composite structure, extending per-pendicular to the open side of the recess and extending along theentire height of the laying unit is considered to constitute a limit case of a protuberance or recessed part.
The boundary faces, serving as toothed engagement faces, ~ -of the projections and withdrawn portions or of the protuberances and recessed parts may be designed as faces extending perpendicu-lar to the particular stressing direction, i.e. parallel to the open side of the recess or horizontal. For reasons connected with the static strength of the composite structure, however, it is advantageous if the vertical toothed-engagement faces form an angle with the upper side of the composite structure and the horizontal toothed engagement faces form an angle with the open side of the recess. If the toothed-engagement faces were to be designed to extend perpendicular to the corresponding direction of stressing, there would be formed, at the location of opening into the remain-~ ing contour of the recess or of the supplementing stone, a cross-- section which would be greatly endangered by stress concentration.
This stress concentration is greatly diminished by inclined for-mation of the relevant toothed-engagement faces.
If it is desired to achieve, at the locations of the composite structure provided with inserted supplementing stones, ~oth a tension resisting horizontal bonding effect and also a vertical bonding effect effective in one vertical direction, then ~- .

. : . , . - : .: . .
.

~0498Z5 according to a subsidiary feature of the invention it is preferred that the projections and withdrawn portions which engage behind each other and which are provided on the facing recesses and on the supplementing stones inserted therein respectively should be designed also to act as protuberances and recessed parts and be confined to a lower zone of the composite structure. In this manner, it becomes possible to provide a composite structure wherein the traction-resisting anchoring of adjacen~ laying units is invisible from the upper surface of the composite structure.
Since the projections and withdrawn portions also assume the func-tion of protuberances and recessed parts, the result is a compara-tively simple mode of assembly of the laying units and of the sup-plementing stones.
If, then, the controur of the entire laying unit is al-ready formed with protuberances and recessed parts it may be ad-vantageous from the manufacturing aspect that also the contour of the recess should have protuberances and recessed parts. Corres-pondingly, there will then be formed in the periphery of the in-serted supplementing stone only recessed parts, so as to permit insertion thereof. Then, there is no associated projéction on the supplementing stone to engage into the recessed parts of the recess.
Moreover, numerous stone shapes are known which can be employed as supplementing stones, for example in accordance with German Auslegeschrift No~ 1,708,675, having protuberances and re-cessed parts at the periphery. Correspondingly, there will then be formed at the contour of the recess only recessed parts so as to permit insertion of the supplementing stone. The recessed parts of the supplementing stone then do not engage over or under any corresponding protuberance of the recess.
Turning to the laying unit for the composite structure according to the invention, these may have recesses in only two ,/;~
., ~ , opposite sides of the laying unit (at least one recess per side) for example if the laying units are laid in cross-bond pattern and the thrust forces are already taken up in the direction per-pendicular thereto due to the kind of laying. However, it is advantageous to form the recesses on all sides of the laying unit.
Thereby there is much less limitation as to the arrangement of the laying units in the composite structure, and a substantially more uniform toothed-engagement of the laying units with one another is provided, For the sake of simpler design of the mould frame for manufacture of the laying units and also of uniform stressing of all the supplementing stones, it is preferred that all the reces-ses should have the same shape.
In the case of laying units of which the elements are identical, it is preferred that the recesses should each be equi-valent in extent to a fraction of the surface area of one element, preferably as a whole-number fraction. It is especially advanta-geous if the recesses are equivalent in extent to one half of the surface area of an element, since then, after placing of the lay-ing units adjacent one another and insertion of the supplement-ing stones, the resulting visual effect is that of a continuous -uniform covering. Addltionally, uniform distribution of the bon-ding forces is achieved, since the forces transmitted from the -supplementing stones are passed on by the elements of the laying unit which in regard to order of magnitude are of like cross-section.
However, it is also possible to provide an arrangement in which the extent of each recess is equivalent to the surface area of at least one element. In this case, the bonding forces are transmitted by supplementing stones which are larger than the individual elements of thé laying unit. However, in place of a relatively large supplementing stone, it is possible to employ a . ' '~

,, ; . : ,, 10498Z'j plurality of parallel-extending supplementing stones having the format of an element.
Preferably, in particular in the case of elements arran-ged in herringbone pattern, the recesses are arranged in mirror-image fashion at a pair of opposite sides of the laying unit.
Neighbouring laying units can then be joined up without offsett-ing at this lateral pair, so that in the case of laying units which (save for the recesses) are rectangular, straight edges are formed at the edges of the laid face parallel to these sides.
Advantageously, the recesses are also arranged at the other pair of opposite sides of the laying unit in mirror-image fashion re-lative to each other. Apart from the simpler mould assembly for the manufacture of the laying units, the risk is eliminated of placing a laying unit incorrectly rotated through 180. In the case of laying units of substantially rectangular contour, it is moreover made possible to cover quadrangular surfaces without need for specially shaped edge units. It is, merely necessary to see that the recesses of the laying units located at the edge of the surface to be laid are completely filled with appropriate sup-plementing stones.
According to a particularly advantageous further develop-; ment of the invention, the element of the pattern is centrally-symmetrical-, of a shape equivalent to two adjoining squares, and having at its four sides protuberances and recessed parts which can be interengaged by parallel displacement of a pair of opposite sides. These elements may be arranged in herringbone pattern (if desired cohering by way of predetermined rupture zones), and they provide an especially strong and well subdivided horizontal bond of the elements relative to each other. The known stones having this shape may be used as supplementing stones subject to appro-priate design of the recesses at the periphery of the laying units.
Within the framework of the invention however the elements may 104~8Z5 have any other desired contour, for example rectangular or a con-tour determined by rectilinearly or curvilinear bounded protuber-ances and recessed parts.
The predetermined rupture zones by means of which the individual elements are held together to constitute a laying unit are contrived for example by means of open free dummy gaps form-ed by recessing the material. These dummy gaps may be provided on the upper side or the underside or on both the upper and under-sides of the laying unit.
Additionally, in the following text the expression l'dummy gap" is to be understood to mean not only an open free dummy jointing gap formed by recessing of material, but also a weakened portion of the material produced by the insertion of any desired type of material strip. Such material strips may comple-tely interrupt the connection between the material of the laying unit adjacent their two sides, such as would be the case for ex-ample with inserted plastics strips, or they may permit a partial local bonding or cohesion of the material of the laying unit on --- the two sides of the inserted strip of material as would be the case with inserted net-like material webs or sheets. Such materi-al webs or sheets may also extend throughout the entire height of the laying unit to provide the predetermined rupture zones.
A particularly preferred further development of the lay-ing unit, wherein at least one predetermined rupture zone is con-trived by dummy gaps provided on the upper and/or lower side of the laying unit involves the arrangement whereby along at least one dummy gap the height thereof varies.
Such a laying unit constitutes an advantageous further development of the laying units described above and is particular-ly suitable for composite structures embodying the invention.
; However, more generally speaking, it has its own inventive signi-ficance.

104982';
The height or level of the predetermined rupture zones in the laying unit must be carefully selected. If they are of relatively small height, then in particular in the case of laying units of relatively large format and upon lateral engagement of the laying units, for example engagement into recesses at the peri-phery thereof, there is a risk that the laying unit may rupture on being handled before having been laid or placed. If on the other hand, predetermined rupture zones of greater height are pro-vided, then it has been found in many cases that the desired rup-turing is difficult of achievement. This applies in particularto covering slabs wherein dummy gaps are provided on only one flat side.
It has been found that, in the case of the laying unit last mentioned, not only is reliable and problem-free separation or severing of the elements achieved along the predetermined rup-ture zones, but also a high degree of protection is obtained a-gainst un-intentional rupture during transport or on lifting by lifting means engaging at the sides. A special advantage of this laying unit resides in that the desired longitudinal profile of the dummy gap can be produced in simple manner by forming suitable projections on the shaped elements used for forming the dummy gaps of the laying unit, or by providing appropriately shaped strips of màterial for insertion.
The predetermined rupture zones may extend at right an-gles to the flat sides of the laying unit or at least part of them may be inclined relative thereto. Concrete is the preferred material.
In a laying unit wherein the height of a dummy gap varies along its length, the variation is preferably regular and/or dis-continuous. Furthermore, a corrugated or serrated configurationof the bottom of the dummy gap is preferred.
Especially advantageous is a form of the laying unit in , . : :
- . . . : :, ' . .

which the dummy gap has at least one section occupying the entire height of the laying unit, the desired rupture zone being sub-divided into a plurality of individual desired rupture sections.
Such a desired rupture zone in turn makes it possible to use a shaped element for insertion into the mould for producing the laying unit, which has the shape of a recessing plate and which is particularly stable and resistant to torsion, since such a recessing plate can extend right down to the bottom of the mould.
In this way warping or flutter of the recessing plate is lessened.
; 10 Clearly if the dummy gaps are formed by insertion of shaped elements (for example recessed plates) into the mould the ; profile of the bottom of the dummy gaps must be such that the shaped elements can be withdrawn from the mould without destroy-ing the profile which it is desired to produce. Generally, under-cut portions with reference to the direction of movement of these shaped elements will be avoided. In some cases however specific undercut portions are advantageous, examples of this will be ; given hereinbelow. ;~
Preferred embodiments of the laying unit, wherein the bottom of the dummy gaps is not undercut with regard to the direc-tion of movement of shaped elements employed to form the dummy gaps may be ascertained from the features of claims 26 to 31.
In particular for the purpose of achieving improved -~ strength of the laying unit for when the latter is extracted from ~, the mould and during transport and when machine laying is employ-ed (whereby for example the laying unit is gripped only at its sides), the laying unit can advantageously be further developed in such a way that an insert is provided in it extending at least from one element to an adjacent element transversely of the inter-posed predetermined rupture zone. In particular if the predeter-mined rupture zones are formed in the lower region of the laying unit, the provision of such an insert effectively improves the .

tensile resistance of the material of the laying unit precisely at these critical locations. Although the described advantages are particularly effective in association with the invention, nevertheless this further-developed laying unit is also of in-dependent inventive significance.
The insert can upon rupturing or fissuring of the pre-determined rupture zones in the laid laying unit, remain sub-tantially undestroyed and in this manner afford a degree of cohesion of the elements of the laying unit which is effective in the horizontal and vertical directions. Such a degree of cohesion is also advantageous if it is required subsequently once again to take up a laying unit. The insert can however also be so designed that on rupture of the predetermined rupture zones it also ruptures at these locations.
Advantageously, the insert extends continuously through the entire laying unit. This mode of design facilitates manufac-ture of the laying units. Especially advantageous from the manu-- facturing aspect is an arrangement whereby the insert is provided parallel to the flat sides of the laying unit.
In a preferred embodiment of the laying units, the insert is in the nature of a flexible net-like three-dimensional struc-ture. The net-like design ensures that the material of the laying unit can bridge thro~gh and across the insert, the flexible design of the three-dimensional structure favours problem-free rupture of the predetermined rupture zones.
According to a preferred, especially simple design of *he laying unit, the insert is designed as a wide-mesh laid, plait-ed, braided, woven or knitted structure comprising elongated strands.
With regard to the material of the insert, it is preferr-ed to employ a plastics, textile, glass fibre or wire insert, or combinations of these materials. The properties of the materials .' ~

- , - . . , : ~ ' ' ~ . . ' :

~049825 employed may be selected within wide limits, depending on the requirements of the object to be achieved. For example there may be employed rupturable,tearable, flexible, stretchable or resilient materials. In the case of laid structures of elongated strands, it is advantageous to employ a design in which parallel-extending first strands are intersected by second strands also extending parallel to each other.
Especially simple to manufacture and in certain fields of application imparting precisely the correct amount of strength is a further development of the laying unit wherein one of the inserts is made from elongated material particles distributed non-uniformly in a plane parallel to the flat sides of the laying unit. These material particles may be of non-uniform or uniform arrangement, or may also for example be concentrated in the laying - unit at the locations of the predetermined rupture zones. As ex-- amples for such elongated material particles, mention may be made of wire sections or also pieces of rubber such as are produced on shredding old tyres.
The manufacture of laying units wherein one or more pre-20 determined rupture zones is contrived by means of dummy gaps provided on the upper and/or lower side of the laying unit can be carried out in a preferred mode whereby a first layer of a mate-rial for the laying unit is introduced into the mould, the insert is laid on to the first layer of the insert, the first layer and the insert are covered with a second layer of material and then the dummy gap or gaps is or are formed.
7 ' Alternatively, the mode of procedure may be such that the mould is first filled with material for the laying unit and then before this has set the insert is applied thereon and finally si-30 multaneously with molding of the dummy gaps the insert is pressed into the material. If in this process shaped elements along com-ponent parts of their length press the dummy gaps right down to - 40 _ . ~
., the underside of the laying unit and leave individual predetermin-ed rupture sections standing between these component parts, the insert also is pressed-through in some of its parts right down to the underside of the laying unit, whereas in the predetermined rupture sections the insert bulges upwards whereby it is disposed in the right location for achieving the strengthening effect.
Just for such a laying unit having dummy gaps which oc-cupy sectionwise the entire height of the laying unit, a preferr-ed mode of manufacture is appropriate wherein the lateral margin-al zones of the predetermined rupture sections in the mould areunder engaged and the under engaged marginal zones are displaced on extracting from the mould. Such under-engagement affords the advantage that even when a lower withdrawable plate is extracted - from the manufacturing mould, the laying unit is retained in par-ticularly effective manner until it is set down on a support or ~ base on which it then sets. This manufacturing process can be - seen in the finished laying unit in that the lateral flanks of the predetermined rupture sections are scored. Such lateral scor-ing may, additionally, also be advantageous for initiating the predetermined rupturing action.
A device for carrying into effect of the last-mentioned process, having a shaping element for forming dummy gap sections occupying the entire height of the laying unit and between which the predetermined rupture sections are arranged, is characterised in that the shaped element has under-engagement projections ending in a narrow edge extending in the direction of the predetermined rupture sections. The under-engagement projections may for ex-ample be shaped so that as seen in plan view they are of trian-gular cross-section providing a cutting edge facing the predeter-mined rupture zones.
The process for laying the laying unit to afford a com-posite structure is characterised in that the laying units are , ~ 1049825 laid, with their recesses facing each other, on a prepared bed and then the supplementing stones are inserted into the facing recesses. Alternatively, the mode of procedure may be such that a laying unit is laid on a prepared bed, supplementing stones are inserted into all its recesses on one side and laying a sec-ond unit adjacent the side of the first so that the recesses on the adjacent side of the second unit engage the remainder of the supplementing stones, the procedure being repeated with fresh laying units and supplementing stones.
DUe to the shape imparted to the laying units and the build-up of the composite structure from laying units and supple-; menting stones, the prerequisite is estabiished for a pYocess which further-develops the invention and which consists in that engagement is effected in each case with gripper means of a grip-per device into the recesses formed in the laying unit and the latter is raised and set down on the bed adjacent the already laid laying units, with a small degree of jointing-gap spacing, and then the gripping means are once again withdrawn out of the recesses.
In this way the laying unit can be moved to the bed by the gripping means and there slowly deposited. If after the lay-ing unit has been set down it is found that the bed has not been satisfactorily levelled and prepared, or if a laying unit has -~ been wrongly~laid, it can be raised once again without difficulty, to permit for example sand to be added or removed. Also on lift~
ing part of the covering laid on a surface, such as is frequently necessary for example when laying or maintaining underground lines, the composite structure according to the invention affords sub- ~
stantial advantages relative to the prior art, due to the fact ~ ~ -that the part of the surface covering requiring to be taken up can be lifted either mechanically or manually and can be re-laid in like manner. Thus, first the relatively light supplementing ' A ~ . 42 -. , . : ., .
- ~ , .
: . , : ' ' :.

stones will be raised manually and extracted from the composite structure, and then, mechanically with the aid of gripping means of a gripper device, the heavy laying units may be raised. On lifting a composite structure devoid of supplementing stones, such a simple mode of operation is impossible.
The gripping means of the gripper device for the laying unit may be of hook-shape or claw-shape and may pass into abut-ment, with positive engagement, into and/or under the recesses formed in the laying unit. ~owever, preferably the gripper means are brought into abutment for tight frictional engagement with the inner contour of the recesses, provided that the weight of the laying unit permits this to be done.

''~ ,~,

Claims (31)

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. A composite paving for traffic areas or other graded or inclined ground surfaces, comprising laying units and linking stones, each said laying unit being a relatively large unitary slab transportable as a unit by being gripped mechanical-ly at opposite lateral sides thereof, said slab having preformed therein elongated rupture zones sub-dividing it into adjoined stones and along which after being laid it is breakable under stress into laterally interengaged individual stones, each said laying unit having in opposed lateral sides thereof at least one recess, said recesses in said lateral sides each extending the full height of the respective laying unit and substantially cor-responding in facial shape and size to one said individual stone or a fraction or multiple thereof, each said unit when laid having at least one lateral side thereof lying at and along, and having therein at least one said recess which confronts a res-pective recess in, a lateral side of at least one other said unit, each set of said confronting recesses being filled by at least one said linking stone inserted thereinto and which inter-connects the respective juxtaposed laying units by extending across the gap between them, each said linking stone having the same height as the laying unit and having substantially the facial shape and size of one said individual stone or of a fraction or multiple thereof, and said rupture zones being so disposed that said individual interlocking stones form a herring-bone pattern wherein a shorter side of each stone lies adjacent part of a longer side of another of said individual stones.

2. A composite paving as claimed in claim 1, wherein said herringbone pattern is uniform and continuous over the entire paving, including said gap.

3. A composite paving as claimed in claim 1, wherein the individual stones and the linking stones are contoured stones having projections and withdrawn portions to peripherally resist horizontal displacements relative to adjacent stones.

4. A composite paving as claimed in claim 1, wherein said stones are provided with protuberances and recessed parts to resist vertical displacements relative to adjacent stones in at least one direction.

5. A composite paving as claimed in claim 3, wherein the projections and withdrawn portions at the same time serve as protuberances and recessed parts and are formed in a lower layer of the composite structure only.

6. A composite paving as claimed in claim 5, wherein the peripheral areas of the individual stones defining the recesses have protuberances and recessed parts, while the peri-phery of the respective inserted linking stone has recessed parts only.

7. A composite paving as claimed in claim 5, wherein the peripheral areas of the individual stones defining the recesses have recessed parts only, while the periphery of the respective inserted linking stone has protuberances and recessed parts.

8. A composite paving as claimed in claim 1, wherein the pattern in which the individual stones are arranged is con-tinued from one laying unit to the next laying unit, with the linking stones being included therein.

9. A composite paving as claimed in claim 1, wherein recesses are provided on all sides of laying units.

10. A composite paving as claimed in claim 1, wherein recesses are also provided at the other opposite sides of laying units which are mirror images of each other.

11. A composite paving as claimed in claim 1, 3 or 9, wherein the laying units are so arranged as to be staggered relative to one another.

12. A composite paving as claimed in claim 1, 3 or 9, wherein each of said individual stones having a quadrilateral contour that is centrosymmetrical and covers an area approxi-mately twice as long as it is wide, and having on and along its four sides lateral projections and withdrawn portions which form at opposite sides of the stone configurations, that by parallel translation of said sides, are identical.

13. A composite paving as claimed in claim 1, wherein at least one predetermined rupture zone is defined by dummy gaps which are provided on the upper or lower sides of the laying units, the height of said dummy gaps varying along one or more of said dummy gaps.

14. A composite paving as claimed in claim 13, wherein said predetermined rupture zone is subdivided into several pre-determined rupture sections by at least one dummy gap section occupying the entire height of the laying unit.

15. A composite paving as claimed in claim 1, 3 or 13, wherein an insert extends from at least one of said individual stones to an adjacent one of said individual stones transversely of said rupture zone therebetween.

16. A composite paving, comprising:
a plurality of laying units formed with recesses in opposed sides thereof;
a plurality of linking stones separately engageable in the recesses of adjacent pairs of said laying units;
each of said laying units having elongate rupture zones along which it is breakable into individual stones; and the linking stones being the same facial shape and size as one of said stones or a fraction or multiple thereof;
and said rupture zones being so disposed that said in-dividual interlocking stones form a herringbone pattern wherein a shorter side of each stone lies adjacent part of a longer side of another of said individual stones.

17. A composite paving as claimed in claim 16, wherein said herringbone pattern is uniform and continuous over the entire paving.

18. A composite paving as claimed in claim 16 or 17, wherein said linking stones are also formed with elongate rupture zones along which said linking stones are breakable into parts.

19. A composite paving as claimed in claim 16, wherein the individual stones and the linking stones are contoured stones having projections and withdrawn portions to peripherally resist horizontal displacements relative to adjacent stones.

20. A composite paving as claimed in claim 16 or 19, wherein said stones are provided with protuberances and recessed parts to resist vertical displacements relative to adjacent stones in at least one direction.

21. A composite paving as claimed in claim 19, wherein the projections and withdrawn portions at the same time serve as protuberances and recessed parts for resisting vertical displace-ments and are formed in a lower layer of the composite structure only.

22. A composite paving as claimed in claim 21, wherein the peripheral areas of the individual stones defining the recesses have protuberances and recessed parts, while the peri-phery of the respective inserted linking stone has recessed parts only.

23. A composite paving as claimed in claim 21, wherein the peripheral areas of the individual stones defining the recesses have recessed parts only, while the periphery of the respective inserted linking stone has protuberances and recessed parts.

24. A composite paving as claimed in claim 16, wherein the pattern in which the individual stones are arranged is con-tinued from one laying unit to the next laying unit, with the linking stones being included therein.

25. A composite paving as claimed in claim 16, wherein the recesses are provided on all sides of laying units.

26. A composite paving as claimed in claim 25, wherein the recesses are provided at opposite sides of laying units and are mirror images of each other.

27. A composite paving as claimed in claim 16, wherein the laying units are so arranged as to be staggered relative to one another.

28. A composite paving as claimed in claim 16, wherein each of said individual stones having a quadrilateral contour that is centrosymmetrical and covers an area approximately twice as long as it is wide, and having on and along its four sides lateral projections and withdrawn portions which form at opposite sides of the stone configurations that, by parallel translation of said sides, are identical.

29. A composite paving as claimed in claim 16, wherein at least one predetermined rupture zone is defined by dummy gaps which are provided on the upper or lower sides of the laying units, the height of said dummy gaps varying along one or more of said dummy gaps.

30. A composite paving as claimed in claim 29, wherein said predetermined rupture zone is subdivided into several pre-determined rupture sections by at least one dummy gap section occupying the entire height of the laying unit.

31. A composite paving as claimed in claim 16, 19 or 29, wherein an insert extends from at least one of said individual stones to an adjacent one of said individual stones transversely of said rupture zone therebetween.