Patent Application
20140199121
The invention relates to a method for manufacturing an actively heatable paved surface consisting of or including block-like paving stones arranged in a plane and each having one horizontal upper face.
For paved surfaces, concrete has nowadays largely ousted other materials for use as paving stones. Natural stone is still today usual in surfaces where the surface effect of the natural material is required. Since concrete blocks can also imitate the surfaces of natural stone thanks to increasing improvement of the compressive strength of concrete and the increasing number of options for detailing their forms, concrete blocks are now ousting naturally quarried materials in this field too.
In regions where ice and snow must be expected, heating of paved surfaces makes sense, for example to make pavements safer by melting away the snow and ice covering. For heating of paved surfaces, it is known for example from DE 10 2006 007 349 A1 how to arrange electric heating mats between the paving bed and the paving stone. It can however occur as a result that over time, the heating mat is damaged by movement of the paving stones due to persons or vehicles passing over the paved surface. In addition, the heating mat can, by covering up the bed, impede the uniform dissipation of forces acting on the paved surface as a result of traffic, so that over time shifting and damage of the paved surface can occur.
Paving stones in which electric heating elements in the form of insulating plates with heating conductors are cast into the concrete or placed onto the paving stones are also known from DE 87 15 218 U1. The electrical contacts are made using metal rails on the paving stones. This design is prone to corrosion outdoors. Shifting or tilting of the paving stones when they are traversed by persons or vehicles can interrupt the electrical connection between individual paving stones.
On the other hand, paving stones made of concrete permit a considerable design latitude. From DE 20 2011 000 442 U1, paving stones are known with grooves on the underside into which heating conductors can be placed. This profiled surface involves multiple benefits in that the grooves permit a close and strong connection to the paving bed and prevent, even under load, any unwelcome movement of the paving stones.
It is desirable to provide a method for manufacturing an actively heatable paved surface with paving stones which simplifies the effort of laying the stones.
According to an aspect of the present invention, a is provided method for manufacturing an actively heatable paved surface by means of a heating system, where the paved surface consists of or includes block-like paving stones arranged in a plane and each having a horizontal upper face, several side faces and one underside, said paving stones having one or more recesses as bottom profiles, in particular channel-like bottom grooves on the underside, comprising the steps:
(a) preparing of a surface to be covered with the paving stones as a paving bed for the paving stones;
(b) preparation of the paving bed in order to obtain a substantially level surface (8a) of the paving bed;
(c) determining a connection position at which one or more heating elements can be coupled to a power supply connection in order to heat at least some areas of the paved surface;
(d) laying out of one or more heating elements on the paving bed in a longitudinal direction in such a way that segments of the heating element(s) are oriented substantially parallel to one another with a first spacing, where the first spacing correlates with a spacing of the recesses;
(e) fixing the laid-out heating elements on the paving bed with one or more paving stones with their bottom profiling being aligned with the laid-out heating elements in such a way that the segments or heating elements are covered over by recesses of the paving stones;
(f) covering the paving bed with further paving stones; and
(g) connecting the heating element(s) to the power supply connection.
The layering of the paving bed with additional paving stones can, particularly, be carried out that the bottom profiling is aligned with the laid-out heating elements in a way that the segments and heating elements, respectively, are covered by the recesses of the paving stones. Advantageously, the heating elements and segments, respectively, then are running in the recesses below the paved surface.
Optionally, installation of one or more heatable block steps can be provided which are supplied with current by the power supply connection or by another separate power supply connection or by a self-contained power supply, e.g. solar modules. The block step can be heated for example by means of built-in heating cables, heating mats and/or heatable coatings or the like.
The recesses can be positioned with an equal spacing of, for example, 5 to 40 mm, preferably 20 mm. By setting individual paving stones for fixing of the heating elements, which are fixed by the recesses in a correspondingly required, and where possible, uniform spacing on the paving bed, less effort is required to lay the overall heating system than in conventional systems available on the market. After complete fixing of the heating elements, the paved surface is installed in the conventional manner.
The recesses can be designed in particular as channel-like bottom grooves on the underside of the paving stone. The bottom grooves can be designed with a trapezoidal or half-round cross-section. When the grooves are filled with the material of the paving bed, they increase the load capacity of the paving stone against horizontally acting forces. Hence horizontal shifting of the paving stones relative to one another, in particular under heavy traffic load, is prevented, and the bottom interlocking of the paved surface is improved. The recesses can preferably have a width between 8 and 20 mm and a height between 7 and 10 mm, which can be easily achieved by manufacture, but does not cause any weakening of the paving stone. Nevertheless, a large quantity of filling material of the paving bed intended for inhibiting movement can collect in the recess. The underside profiling leads to an engagement of the paving stone in the paving bed and results in a high degree of safety against shifting caused by horizontal loading effects. This results in a very high stability and resistance to shear and rotation forces. The friction coefficient is increased by more than 50% relative to a smooth underside of the stone.
It is furthermore advantageous that no expensive and cut-to-size heating mats are needed. Conventional heating cables having an appropriately adapted cable cross-section for a required heating effect can be securely inserted by the building contractors into recesses inside the surface to be heated. The heating cables are securely placed into the recesses in the case of movements of the paved surface.
Thanks to the recesses, the heating cables are close to the surface to be heated. The paved surface can be heated within a short time with a low energy expenditure, the result being that in a short period of time, with less energy and hence with lower costs, the surface can be kept free of snow and ice.
The paving bed is not interrupted by the heating elements, so that the paving bed is not impaired in its function of uniformly absorbing forces when the paved surface is traversed by persons or vehicles.
The connection between paving bed and paved surface is increased by the recesses, since bed material engages in the recesses and hence shear forces are evenly transmitted from the paved surface over the paving bed. Shifts and twists of individual stones of the paved surface are hence prevented.
A heating conductor or a heating pipe can be preferably inserted as the heating device. This allows the geometry of the underside profiling to be matched to the diameter of heating conductors or heating cables or heating pipes to enable heatable concrete surfaces to be provided. Heating conductors are supplied with electric current. Alternatively, it is conceivable to use liquid-heated or air-heated heating elements in the form of heating pipes that prevent icing of the paved surface by connection to a district heating system, building heating system or similar. The laying of heating conductors or heating pipes underneath paving and slabs is facilitated by the underside profiling such that a frost-free traffic surface, for example a stairway or garage entrance, can be created. The laying of large-area heating mats having a detrimental effect on the interlocking between paved surface and sub-grade is no longer necessary. In addition, it enables repairs to be performed without removing the paving, for example a defective section of the heating device underneath the paved surface is pulled through and out and a new section is inserted at the same time.
During laying of the heating elements, those heating elements which are longer in the longitudinal direction than the paving bed surface to be covered can be advantageously bent around at the edge of the surface to be paved and reversed parallel to the already laid segment of the heating element. Nested geometries of the surface to be paved can be heated over its full surface using the heating elements flexibly inserted into the existing grooves. Heating mats by contrast result due to their geometry in an unflexible and restricted geometry and size.
Advantageously, a joint which can be filled with a joint material can pass between the lateral surfaces of adjacent paving stones. This ensures a drainage capacity of the paved surface, i.e. rainwater or dew water can seep away in a defined manner through the paved surface—via the joints.
Advantageously, the paved surface comprises paving stones which have at least two ridges on each lateral surface facing each adjacent paving stone, said ridges each having a rib and a flat element, where the rib projects with a thickness of around 65% to 90% of the joint width into the joint and that those points of the rib projecting furthest inwards form a plane parallel to the lateral surface, the plane running from the bottom up to close to the upper face and vertically to the upper face, where the rib adjoins the flat element which projects into the joint with a thickness of around 35% to 90% of the joint width, but less so than the rib, and extends from the underside only over part of the lateral surface, where inside the area of the joint between two adjacent paving stones at least one pair of ridges is arranged such that it precisely encloses a ridge on the opposite lateral surface in such a way that the flanks of the ridge measured in the joint longitudinal direction are opposite with a spacing of 10% to 120% of the joint width. The material and/or the grain size of the joint material are selected here to be finer than the material of the paving bed.
A paved surface in accordance with the invention offers numerous advantages, including that when a certain horizontal force is exceeded the individual paving stone shifts on its bed until its ridges on the lateral surface engage with the opposite ridges of the adjacent stone. As a result, this stone also gives support to its overloaded neighbour. In the same way, the overloaded stone will brace against its neighbour on the other side. If these too begin to shift in their paving bed, they will in turn brace against their respective neighbour. In this way, a peak load on several stones can be evenly distributed. The weakest link in the chain of force distribution is the ridge of the originally overloaded stone: the stronger it is designed, the higher the loading limit. It is particularly advantageous when a ridge is, particularly in its lower half, very much stronger than other previously known ridges. This results in a marked increase in the respective loading capacity. A paving stone of this type is known from DE 20 2011 000 442 U1, the disclosure of which is here completely covered by reference thereto. DE 20 2011 000 442 U1 describes a paved surface with an advantageous paving stone having outstanding drainage properties, although the paving stone itself is not water-permeable. In combination with the active heatability of the paved surface manufactured in accordance with the invention, obvious advantages are resulting, since for example dew water does not linger on the paved surface.
A further advantageous function of the ridges is the relatively narrow rib reaching relatively close to the surface. This helps to form a proper joint during laying. Even if the paving stones are laid in an (incorrect) manner touching one another and/or with absent or partial or unsuitable filling, there is always still a minimum joint between the paving stones. In this situation too (not desired by the invention), only the upper edges of the narrow ribs split off first in the case of overloading.
Advantageously, the special ridge shape permits the formation of defined joints with paving stones interlocking with one another. Thanks to the particular selection of the grain of the joint material, which must be made finer than that for the paving bed, said grain being preferably 0.2 to 0.6 times smaller than the joint width, in particular 20% to 60% of the joint, it is possible to achieve a high drainage capacity of the paved surface with a strong bond at the same time. Hence a long-term drainage capacity with more than 270 l/(s×ha) can be achieved. By the specific shaping of the spacer ridges (two adjacent ribs with varying depths of 3 and 4 mm, for example), which can engage in the opposite ridges of the neighbouring stones, it is for example possible to obtain a homogeneous 5 mm joint. In conjunction with a joint material of for example ⅓ grit (average grain size 1 to 3 mm), a paving bed material of for example ⅖ grit (2 to 5 mm grain size) and the all-round ridge interlocking, the aforementioned long-term drainage capacity is achieved such that a paved surface can be created which, without the use of porous paving stones having a self-drainage capacity, can comply with and even far exceed the valid specifications. For example, the DWA (German Association for Water, Wastewater and Waste) and the FGSV (Research Society for Roads and Transport) specify a drainage capacity in paved traffic surfaces of over 270 l/(s×ha) even after lengthy use and possible clogging of the joint due to dirt ingress. A paved surface in accordance with the invention permits a drainage capacity which is more than 10 times higher, which is achieved substantially by the joint geometry, subject to the ridge shape and the use of a joint material which has a permeability of at least 5.4×10-4 m/s according to DIN 18130 and is filter-stable relative to the bed material. It is thus possible to dispense with previously used drainage-capable and porous stones, such that the resistance of the paved surface to frost and de-icing salt is significantly increased. A paved surface in accordance with the invention can be laid in the public domain to be both durable and of lasting value over an extremely long service life.
The individual stones of the paved surface can have a format of any required size. Dimensions of 20×20 cm or 20×10 cm have, like the size 16×16 cm, proven to be advantageous. These sizes permit problem-free laying, a sufficient joint area and well-defined joint design per square meter, as well as a strong, weather-resistant and heavy-duty paved surface over a long period of time.
In the event of a heavy load on the paving stone, it is—as already described several times—set in a rotary motion. This results, as is well known, in a compacting of the joint material in the upper part of the joint. Due to the finer consistency of the joint material, a good hydraulic conductivity through the joint is still assured even if it is compacted. Thanks to the special design of the ridges with a broad and flat element not projecting so far into the joint as the narrow rib, a paved surface in an embodiment has a particularly voluminous joint in comparison with other systems, which also reduces the joint width considerably only in the narrow portion of the narrow ribs. For that reason, the paving stones of a paved surface in accordance with the invention have a smaller tilt angle than other systems under the same load.
With the aforementioned type of filling of the joint, the achievable loading limits can be increased and an above-average drainage capacity can be achieved. A strengthening of the positive effect of the joint with ridges in accordance with the invention is achieved when the joint is filled with sand, gravel sand, crushed sand, grit or a mixture thereof, where the grain size of this joint material should be 0% to 100%, preferably 20% to 70%, of the joint width. A fine grain size in the range from 20% to 70% of the joint width permits homogeneous filling of the joint material such that the stones opposite are insulated by joint material and emplaced tilt-proof, ensuring a high drainage capacity. The joints achieved using the ridges, in combination with the proposed joint material, allow a required coefficient of permeability (hydraulic conductivity) of at least 5.4×10-4 ms to be achieved.
In a favourable embodiment, the joint can have a width of around 3.5 mm to 6.5 mm, preferably 4.5 mm to 5.5 mm, in particular 5 mm. The rib can have here a thickness, i.e. a projection into the joint in the direction of the lateral surface of the adjacent stone, of around 2.5 mm to 5 mm, preferably 3.5 mm to 4.5 mm, in particular 4 mm, and the flat element can have a thickness of 1.5 mm to 4 mm, preferably 2.5 mm to 3.5 mm, in particular 3 mm. Hence a joint with an average minimum width of about 4 to 5 mm can be created which ensures a sufficient drainage capacity commensurate with the size of the paving stone, and permits a closely interlocking and visually attractive row of paving stones to be laid, so that both long-term resistance and traffic safety can be achieved. The joint proportion of the surface to be provided can, in conjunction with the aforementioned joint material according to DIN 18130 or on the basis of infiltration tests, permit a sufficient drainage capacity of at least 270 l/(s×ha) (liters per second and hectare).
In the interests of a high drainage capacity and durability of the system, an embodiment is preferred where the grain size of the joint material is finer than the grain size of the paving bed. Advantageously, the joint material can have a grain size of about 40% to 100%, better still 50% to 90% of the paving bed material and preferably 60% to 85%, where in particular the joint material is a 1-3 mm filling material and the paving bed material is a 2-5 mm filling material. Thanks to the refined yet similar and filter-stable grain of the joint material relative to the paving bed material, a high resistance to high traffic loads such as that from trucks is achieved while providing a high drainage capacity. The stones are, due to the defined joint geometry and the interlocking effect of the ridges together with the joint filling, reinforced against one another by means of fine joint material, where a finer joint filling is more resistant to clogging or to a declining drainage effect than a coarser filling. With increasing drainage of the surface water, the grain size of the sub-grade too increases such that improved water drainage is achieved. Right at the bottom of the joint, at the transition between joint and paving bed too, an improved drainage capacity and elastic deformation between the grains of the fine-grained joint material and the coarse-grained paving bed is achieved under peak loads. If for example a paved surface is designed such that it can be continually traversed by trucks, then the number of equivalent axle loads from heavy traffic is reduced by the joint material having a grain size from 60 to 90% of the joint width. Hence only a few trucks can traverse the paved surface, with a coarser grain ensuring a better drainage capacity of the paved surface.
An advantageous paved surface can be designed advantageously such that at least two neighbouring stones are adjacent at one lateral surface, i.e. with block-like paving stones in only one direction the joints run straight, and in the other direction oriented transversely thereto the joint is offset from stone to stone by half a stone width each time. A design in accordance with the invention of the lateral edges of paving stones is of course possible and sensible for polygonal stone shapes too. Interesting shapes are for example hexagonal or octogonal, and also possible are rhomboids and trapezoids as well as all other polygons, as known for example from the field of wall tiles.
With this type of paved surface, active heating can be particularly advantageously assured by the method in accordance with the invention.
As a minimum requirement for the lateral surfaces, it is favourable that a single ridge is arranged on a lateral surface such that it fits into the cavity between a pair of ridges on the opposite lateral surface with a spacing of 10% to 120% of the joint width in each case. This spacing is useful since joint material poured into it ensures an even distribution of forces. The combination of a ridge pair on the one lateral surface with a single ridge on the other one safeguards the two neighbouring stones against horizontal movements in both directions, i.e. against braking and acceleration of vehicles.
Proceeding from the aforementioned embodiment, a heating device, preferably a heating conductor or a heating pipe, can be inserted along at least one recess between the paving bed and the underside of the paving stone. In this way the geometry of the underside profiling can be matched to the diameters of heating conductors or heating cables or heating pipes to enable heatable concrete surfaces to be provided. Heating conductors are supplied by electric current. It is alternatively conceivable to use liquid-heated or air-heated heating pipes that can prevent icing of the paved surface by connection to a district heating system, heating system of a building or similar. The laying of heating conductors or heating pipes underneath paving and slabs is facilitated by the underside profiling such that a frost-free traffic surface, for example a stairway or garage entrance, can be created. The laying of large-area heating mats having a detrimental effect on the interlocking between paved surface and sub-grade is no longer necessary. In addition, it enables repairs to be performed without removing the paving, for example a defective section of the heating device underneath the paved surface is pulled through and out and a new section is inserted at the same time.
Further advantages are derived from the following description of the drawing. The drawing shows embodiments of the invention. The drawing, the description and the claims contain numerous features in combination. A person skilled in the art will expediently also view the features individually and group them to form meaningful further combinations.
The drawing shows schematically in:
a-5e various intermediate steps during manufacture of a paved surface using the method in accordance with the invention;
The examples shown in the figures must only be regarded as typical and are not intended to be restrictive. Elements which are the same or have the same effect are identified with the same reference numbers in the various figures.
The heating element 19a can consist of or comprise one or more electric heating cables or heating strips. A long heating cable can be provided here that is routed forward and then back on the underside of the paved surface 100, or several heating cables wired in series and/or in parallel can be provided, or combinations of long and short heating cables. Also conceivable are one or more appropriately configured and interconnected heating tubes through which a medium passes.
In two of the three transverse channels 20, heating devices 19 in the form of heating conductors or heating cables are inserted and can heat the paved surface 100 (
For example, the paving stone 1 shown can have dimensions of 16×16 cm, where the two heating conductors 19 are at a distance of 8 cm from one another. Other dimensions are of course also possible.
It can be discerned that the paving stone 1 can dig tightly into the paving bed 8 thanks to the recesses 12, so that the heating conductors are firmly enclosed by the paving bed 8. The close contact with the paving bed 8 advantageously stabilises the position of the paving stone 1, and the heating conductor too is enclosed and securely fixed inside the recess 12.
a to 5e show different intermediate steps during manufacture of a paved surface 100 using the method accordance with the invention.
a shows that a surface 110 is prepared which must be covered by the paving stones 1. The surface 110 acts as a paving bed 8 for the paving stones 1. The surface 110 to be paved can be prepared in the conventional way. In the next step, the paving bed 8 is leveled so that its surface 8a is sufficiently flat.
b shows the determination of a connection position 72 at which one or more heating elements 19a can be connected to a power supply connection 70 for heating at least some parts of the paved surface 100. The electric current outlet for the electric heating cables is determined and the exiting heating cables 19a are fixed with a paving stone 1.
A pre-drilled paving stone can later be laid at this point, into which a moisture and temperature sensor (not shown) can be inserted. This sensor automatically regulates, together with an ice indicator which can be fitted indoors, when the paved surface 100 is heated. It is of course possible to activate heating of the paved surface 100 manually.
c shows several segments 19b of a heating element 19a of the heating system 19 laid out parallel in a longitudinal direction L on the paving bed 8. Only a few of the segments 19b are identified with reference numbers. The heating element 19a can for example be a long heating cable of which a segment 19b is laid as far as the edge of the surface 110 to be paved, with the heating cable then being bent round so that a further segment 19b can be routed back parallel to the first segment (
It is also conceivable that several separate heating cables are laid out and electrically connected. The segments 19b of the heating element(s) 19a are oriented substantially parallel to one another at a first distance dl, where the distance dl correlates with a distance of the recesses 12 of the paving stones.
The laid-out heating cable (heating element 19a) is fixed on the paving bed 8 with one or more paving stones 1 with their bottom profiling 12a being aligned with the laid-out heating elements 19a. As a result, the segments 19b or heating elements 19a are precisely covered by the recesses 12 on the underside of the paving stones 1. It can be seen in
The paved surface 100 can then be formed by gradually covering the paving bed 8 with further paving stones 1, as shown in
When the surface 100 is fully paved, the paving stones 1 are conventionally compacted using a vibrator to obtain a required final height in the paving bed 8. The paving bed 8 engages here in the recesses 12, so that the heating cables are securely enclosed like inside protective tubes in the recesses 12.
With appropriate sensors, the completed and connected-up paved surface 100 can be automatically heated. The moisture and temperature sensor switches the heater on when required, in good time before ice and snow forms, and switches it off again when the ambient conditions are suitably milder.
The block step 50 can be contacted using electrical connections projecting outwards from the heating device 19x or the heater coating 19z, for example on the lateral surfaces of the block step 50, and is connected to the power supply connection 70 or to a separate power supply connection (not shown). The power can also be supplied by solar modules.
An interaction of the heating device 19 (
