U.S. patent application number 10/597778 was filed with the patent office on 2007-09-27 for water-permeable paving and method for producing a paving.
This patent application is currently assigned to TERRAELAST AG. Invention is credited to Roger Hartenburg.
Application Number | 20070223998 10/597778 |
Document ID | / |
Family ID | 34801750 |
Filed Date | 2007-09-27 |
United States Patent
Application |
20070223998 |
Kind Code |
A1 |
Hartenburg; Roger |
September 27, 2007 |
Water-Permeable Paving and Method for Producing a Paving
Abstract
The invention relates to a water-permeable paving (1), for
application on a ground. The upper part (6) of the paving (1)
comprises a combination of compacted mineral aggregate and organic
adhesives. Said paving (1) has a multilayered structure with an
upper part (6) and a lower part (2), whereby the lowerpart (2)
comprises at least one layer of sand (4) on the side of the ground
and one layer of gravel (5) on the side of the upper part, the
average size k.sub.Schotter of the fine particles being 5 mm. The
invention also relates to a method for producing said paving.
Inventors: |
Hartenburg; Roger;
(Lampertheim, DE) |
Correspondence
Address: |
OSLER, HOSKIN & HARCOURT, LLP (OTHER)
1000 DE LA GAUCHETIERE STREET WEST
SUITE 2100
MONTREAL
QC
H3B-4W5
CA
|
Assignee: |
TERRAELAST AG
Mitterfeldstrasse 2
Sauerlach
DE
82054
|
Family ID: |
34801750 |
Appl. No.: |
10/597778 |
Filed: |
January 14, 2005 |
PCT Filed: |
January 14, 2005 |
PCT NO: |
PCT/DE05/00046 |
371 Date: |
January 15, 2007 |
Current U.S.
Class: |
404/31 |
Current CPC
Class: |
E01C 11/226 20130101;
E01C 7/32 20130101; E01C 7/30 20130101 |
Class at
Publication: |
404/031 |
International
Class: |
E01C 13/00 20060101
E01C013/00 |
Foreign Application Data
Date |
Code |
Application Number |
Feb 7, 2004 |
DE |
102004006165.3 |
Claims
1. Water-permeable ground covering (1) for application to a
substratum, wherein the superstructure (6) of the ground covering
(1) is a combination of compacted, mineral aggregates and organic
binding materials, characterised in that the ground covering (1)
has a multi-layered structure with a superstructure and a
substructure (6 and 2 respectively), with the substructure (2)
having at least one layer of sand (4) on the substratum side and a
layer of ballast (5) on the superstructure side, the average size
k.sub.ballast of the undersize particles of which amounts to 5 mm
or more.
2. Ground covering according to claim 1, characterised in that
layers of the superstructure and/or of the substructure (6 and 2
respectively) are connected together by bonding.
3. Ground covering according to one of the preceding claims,
characterised in that the granulation of the aggregates k.sub.z
amounts to 1 to 7 mm.
4. Ground covering according to one of the preceding claims,
characterised in that the average layer thickness d.sub.o of the
superstructure (6) amounts to 30 to 60 mm.
5. Ground covering according to one of the preceding claims,
characterised in that the voidage of the superstructure (6) amounts
to up to 45%.
6. Ground covering according to one of the preceding claims,
characterised in that the mineral aggregates comprise a selection
of quartzite, granite, basalt and quartz.
7. Ground covering according to one of the preceding claims,
characterised in that the mineral aggregates have a narrow
grain-size distribution, with the average size d.sub.k of the grain
amounting to a range between 1 to 3 mm, 2 to 3 mm, 2 to 4 mm, 2 to
5 mm or 3 to 7 mm.
8. Ground covering according to one of the preceding claims,
characterised in that the mineral aggregates have a mixture of
round grain and at least a proportion of 20% angular grain.
9. Ground covering according to one of the preceding claims,
characterised in that the binding material is a two-component epoxy
resin binding material or a one-component polyurethane binding
material or a two-component polyurethane binding material.
10. Ground covering according to one of the preceding claims,
characterised in that a proportion of the aggregates of the
superstructure (6) are coloured and the proportion preferably
consists of quartz sand.
11. Ground covering according to one of the preceding claims,
characterised in that the average layer thickness d.sub.sand of the
compacted layer of sand (4) amount to at least 20 mm.
12. Ground covering according to one of the preceding claims,
characterised in that the layer of ballast (5) has undersize
particles, whose average size k.sub.uballast amounts to 5 mm or
more.
13. Ground covering according to one of the preceding claims,
characterised in that the average grain size k.sub.ballast of the
ballast (5) lies in a range between 5 to 16 mm, 16 to 22 mm or 16
to 32 mm.
14. Ground covering according to one of the preceding claims,
characterised in that the average layer thickness d.sub.s of the
layer of ballast (5) amounts to 400 to 500 mm.
15. Method for producing a ground covering according to one of the
preceding claims, characterised by the following method steps:
application of a still deformable mixture of binding material and
sand to the substratum (3), compacting of the binding-material/sand
mixture, application of a still deformable mixture of binding
material and ballast (5) to the layer of sand (4), application of
the upper layer consisting of a still deformable mixture of
aggregates and binding material to the layer applied last,
compacting of the still deformable mixture, and hardening of the
layers.
16. Method according to claim 15, characterised in that the
superstructure (6) is applied to the substructure (2) even before
the layer of the substructure (2) on the superstructure side has
completely hardened.
17. Method according to claim 15 or 16, characterised in that a
layer of sand (4) is applied after the layer of ballast (5) has
been applied.
18. Method according to one of the claims 15 to 17, characterised
in that before the layer of ballast (5) is applied to the layer of
sand (4), a layer of binding material is applied to the layer of
sand, for example by spraying.
19. Method according to one of the claims 15 to 18, characterised
in that before the superstructure (6) is applied to the layer of
ballast (5), a layer of binding material is applied to the layer of
ballast (5), for example by spraying.
20. Method according to claim 18 or 19, characterised in that the
depth of penetration t of the layer of binding material amounts to
at least 150 mm.
Description
[0001] The invention relates to a water-permeable ground covering
for application to a substratum, in which case the superstructure
of the ground covering is a combination of compacted, mineral
aggregates and organic binding materials. The invention further
relates to a method for producing a ground covering.
[0002] The consolidation of surfaces by ground coverings to produce
roads, public places, building covers and other surfaces on which
it is possible to walk or drive is a well-known technique.
Concrete, asphalt, stone and wooden coverings are common. The
disadvantage with regard to draining off surface water is the low
level of or even absence of water-permeability; there is therefore
often talk of a sealing of the surfaces, attempts being made to
deal with this by means of drainage systems, which in most cases
are expensive.
[0003] An ecologically undesirable phenomenon accompanying
surface-sealing is the increased loading on river courses that
change into raging torrents when there is heavy or persistent
downpours of rain or as a result of melt water. The consequences
are catastrophic: ever more frequently floods occur, communal
sewage plants are overloaded and fail, groundwater levels drop.
[0004] Further demands are made with regard to constructional
properties. These relate to performance in the event of moisture,
resistance to pests, acoustic properties, reaction to chemical
influences and to fire. The durability of a ground plays a big role
as the most important demand, with properties such as
pressure-resistance, bending tensile strength, wear-resistance to
drag, rolling, impact and shock, resistance to pressing-in
representing significant constructional parameters.
[0005] For special applications, such as, for example the
construction of riding and sports grounds, plastics grid plates
have proved good. Such grid plates are known from DE 197 20 006 C2.
As a result of an ingenious structure of elevations and openings,
on the one hand grid plates enable there to be
surface-consolidation on which it is possible to walk or drive and
on the other hand avoid sealing as a result of their
water-controllability.
[0006] The areally laid grid plates are laid directly on the
substratum, such as gravel, grass, loam or humus. A layer of sand
or ballast can, however, also be applied to the substratum in order
then to lay grid plates on this layer. It is possible to compensate
for instances of unevenness in the ground by means of the layer of
sand or ballast. Depending on the use of the sports ground, if
applicable a tread layer is applied to a thickness of several
centimetres. The tread layer, which together with the grid plates
forms the superstructure of the sports ground cover, in the case of
riding grounds as a rule consists of a bedding of sand, of a
bedding of sand provided with aggregates (wood or plastics chips)
or exclusively of wood chips. Depending on the stress and strain
and composition of the tread layer, the latter has a thickness of
between 8 to 15 centimetres, measured from the upper plate of the
grid plates.
[0007] The comparatively high costs of grid plates when laid out on
large areas and also their uneven structure are disadvantageous,
however.
[0008] Coverings with a surface structure that is uniform and
visually attractive are known from DE 197 33 588 A1. The
water-permeable covering is produced from mineral aggregates and
organic bonding agents. The mixture is built up in the not yet
hardened and deformable state. Mostly organic binding materials
come into consideration as binding material that is mixed together
with mineral aggregates to form a charge and is processed further
before hardening.
[0009] What is disadvantageous about these coverings consisting of
bound mineral aggregates is the lack of bonding with the
substratum, this impairing the mechanical stress and strain
precisely in the case of freeze-thaw cycling in grounds that are
outside. Chemical, physical and biological corrosion of building
materials, weathering, destruction of the subsoil lying underneath
can result from this.
[0010] It is precisely public building promoters therefore who want
to have ground coverings that do not seal the surfaces and allow
large areas which bear high mechanical loads, for example as a
result of vehicles, in a problem-free manner, to be covered
inexpensively.
[0011] Against this background an object of the invention is to
specify a water-permeable ground covering of the type in the
preamble which even in the case of complex shapings is inexpensive
in comparison with known ground coverings and grid systems. As
regards the mechanical loading capacity, the ground covering should
not result in any limitations in the use of the covered areas. In
addition, a method for producing a ground covering is to be
specified that allows the covering to be laid in a simple and
inexpensive manner.
[0012] In accordance with the invention, the object that is set
with regard to the ground covering is achieved by means of the
features of claim 1. Accordingly, the ground covering has a
multi-layered structure with a superstructure and a substructure,
with the substructure having at least one layer of sand on the
substratum side and a layer of ballast on the superstructure side.
The average size k.sub.ballast of the undersize particles in the
ballast amounts to 5 mm or more.
[0013] In practice, it has been identified that the service life
and loading capacity of a covering consisting merely of grid
systems or bound, mineral aggregates is limited. As a result of the
structure of the covering in accordance with the invention
consisting of a superstructure and a substructure it is possible to
adapt the positive properties with regard to the water-permeability
of a superstructure, consisting of bound, mineral aggregates,
universally to the substratum. The bulk material of the
substructure enables there to be uniform load-distribution in the
substratum that lies underneath so that even punctiform pressure
loads that act on the superstructure are introduced into the
substratum so that they are distributed over a large area over the
layer of sand on the substratum side and thus the static and
dynamic pressure-loading capacity of the superstructure is
decisively improved in comparison with known solutions.
[0014] A further improvement is brought about by the substructure
in its water-permeable passage to the superstructure as regards
water-controllability. It is precisely in the case of a critical
substratum that has a high proportion of loam that the substructure
is able to supplement the water-storing capacity of the
superstructure. Thus the surface water is taken up by the
substructure through the superstructure and is distributed
horizontally. Thus enormous quantities of water can be taken up
within a short time and stored temporarily until the substratum or
further drainage facilities drain off the water. This drainage
capacity can be attributed to the high voidage so that problem-free
installation is possible even in water-protection regions. This
voidage as well as different rock sizes and sorts of materials
result in excellent sound-absorption.
[0015] Tests have shown that the ground covering in accordance with
the invention is able to demonstrate excellent water-absorption
values. In a field analysis, the water-absorption values of the
ground covering were determined and compared with the values of a
conventional water-permeable sports-ground construction in
accordance with DIN 18 035-6, section 5.1.6.3 and 5.1.6.2. In this
connection, the requirements of DIN 18 035-6 were met many times
over. Thus a sample with a layer thickness d of the superstructure
of 47 mm resulted in a water-absorption value k*=0.51 cm/s. The
requirement according to DIN 18 035-6, Table 3, amounts to >0.01
cm/s.
[0016] The grain size of the ballast in the substructure has a
further favourable effect upon the water-absorption value and
water-controllability of the ground. This promises excellent values
given an average grain size for the undersize particles of 5 mm or
more. Tried and tested average grain sizes k.sub.ballast of the
ballast lie in a range between 5 to 16 mm, 16 to 22 mm or 16 to 32
mm. That means that the layer of ballast is composed of ballast
with different grain sizes, with the grain of a layer of ballast
lying in one of the ranges mentioned. The average layer thickness
d.sub.s of the compacted layer of ballast preferably amounts to
between 400 and 500 mm.
[0017] The grain size of the aggregates also has a substantial
influence on the infiltration capacity of the ground covering.
Aggregates whose average grain size lies between 1 and 7 mm are
particularly preferred. As previously mentioned, the layer
structure of the ground covering in accordance with the invention
has a favourable influence on the mechanical resistance values so
that even values of over 5 mm are possible for the average size of
the grain without a substantially increased risk of rupture
occurring. The infiltration capacity can be further increased with
this grain diameter. In addition, with these values the drop in
infiltration capacity as a result of the entry of mineral and
organic fine parts over time remains low.
[0018] The open-pore structure of the superstructure results in
high coefficients of friction on the surface so that the ground
covering is suitable as a non-slip cover for carriageways,
footpaths, steps and presentation spaces and thus reduces the risk
of accidents.
[0019] Favourable layer thicknesses for the superstructure with
regard to pressure-loading capacity and good water-permeability lie
between 30 and 60 mm. Of course, lower values are also possible, in
which case then concessions have to be made with regard to
pressure-loading capacity. Greater layer thicknesses for the
superstructure only bring about slight improvements for the
pressure-loading capacity and increases the costs of a ground
covering. The optimum for most cases of application therefore lies
in the range mentioned above.
[0020] Generally, the grain-size distribution is defined according
to DIN 66145. The parameter n amounts to at least 9 and is
determined whilst disregarding 1% oversize and undersize particles
in each case.
[0021] The binding material is preferably a two-component
polyurethane binding material. A two-component epoxy resin binding
material or a one-component polyurethane binding material can be
used in exactly the same way. Two-component epoxy resin binding
materials are made available, for example, by the firm of Koch
Marmorit under the trade name Kryorit.
[0022] An important advantage of the use of two-component epoxy
resin binding material can be seen in its environmental
compatibility. The ground covering in accordance with the invention
does not, for example, have any toxic effect at all upon mould
fungi and is considered difficult to break down microbially.
Nevertheless, substances that can be eluted from the ground
covering can easily be broken down, as material tests have shown.
As washing tests prove, there is no chemical interaction between
surface water and the covering materials so that surface water that
seeps through the covering can be introduced into the sewerage
system in an untreated state or can safely drain off into the
groundwater. Finally, the ground covering in accordance with the
invention can be disposed of after its phase of use in an earth--or
ballast-washing system without any negative environmental effects.
Alternatively, after comminution, reuse thereof as granular
material is also possible.
[0023] When processing the binding material, two methods are
distinguished. If the components of the superstructure or
substructure that are present as chippings or sand are to be
stabilized, these are advantageously mixed with the previously
homogenized binding agent in situ and laid out. When ballast or
other comparatively coarse granular material is stabilized, epoxy
resin or polyurethane and hardeners are also mixed in situ and
sprayed in liquid form onto the ballast surface. The binding agent
flows into the depths and thereby bonds the individual ballast
grains or the granular material one with the other.
[0024] The binding materials mentioned as a result of the high
binding force enable any bulk materials to be combined as a result
of very good adhesion in the range of adhesive and capillary
action. This additionally contributes to the static and dynamic
pressure-loading capacity of the ground covering that has been
mentioned. Bonding of adjacent layers of the superstructure and
substructure is particularly effective for high loading capacity so
that it is also possible for vehicles to drive on the ground
covering.
[0025] Very often for a visually attractive configuration of spaces
colouring of the ground is desired. By using coloured quartz sand
or natural stones as an aggregate it is possible to choose from
over 200 colour variations so that practically no limits are set on
the coloured configuration of a ground covering. Architects in
particular know how to use these coloured effects in an impressive
way.
[0026] In addition to the static and dynamic resistance values that
are important for suitability as a carriageway-covering, the ground
covering in accordance with the invention as a result of the high
voidage also absorbs the sound of vehicles in a clearly better way
than, for example, asphalt. Particularly favourable values result
in the case of a voidage of at least 45% in the superstructure.
[0027] Further advantageous embodiments of the invention with
respect to the ground covering follow from the features of claims
11 to 14.
[0028] In accordance with the invention the object that is set with
regard to the method for producing the ground covering is achieved
by means of the features of claim 15. Accordingly, the production
is effected in accordance with the following method steps: [0029]
application of a still deformable mixture of binding material and
sand to the substratum, [0030] compacting of the
binding-material/sand mixture, [0031] application of a still
deformable mixture of binding material and ballast to the layer of
sand, [0032] application of the upper layer consisting of a still
deformable mixture of aggregates and binding material to the layer
applied last, [0033] compacting of the still deformable mixture,
and [0034] hardening.
[0035] Intensive bonding of the layers one with the other results
if directly after compacting the first layer the next layer is
applied before the layer that lies underneath hardens. This calls
for uninterrupted application and compacting layer by layer.
[0036] Further advantageous embodiments of the invention with
respect to the ground covering follow from the features of claims
16 to 20.
[0037] Advantageous embodiments of the invention are explained in
the following with reference to the attached drawing, in which:
[0038] FIG. 1 shows a diagrammatic cross section through a ground
covering that has been applied to a substratum with a double-layer
substructure, and
[0039] FIG. 2 shows a diagrammatic cross section through a ground
covering that has been applied to a substratum with a three-layer
substructure.
[0040] FIG. 1 graphically shows in a cross section the
multi-layered structure of the ground covering 1 in accordance with
the invention. In the present exemplary embodiment the latter has
three layers, the lowest course of which, the substructure 2, is
applied to a substratum 3. Before the substructure 2 can be
applied, the substratum 3 must first be prepared. This is dug to a
frost-resistant depth of 40 to 60 cm. This digging depth is
recommended so that the connection between the substructure 2 and
the substratum 3 remains unaffected by the erosive effects of
freeze-thaw cycling.
[0041] The substructure 2 itself is composed of a course of sand on
the substratum side, the so-called layer of sand 4, and the layer
of ballast 5 lying on top. For this is first added a charge of
binding material and sand that are mixed together. The binding
material is a two-component polyurethane binding material. A
two-component epoxy resin or a one-component polyurethane binding
material can be used in exactly the same way. After the charge has
been added, the mixture is then to be processed without
interruption as long as it is still deformable and has not
hardened. This takes place by applying the layer of sand 4 to the
substratum 3 in an as uniform and planar manner as possible. The
layer thickness d.sub.sand of the compacted layer of sand 4 amounts
to at least 20 mm.
[0042] After the compacting and the hardening, which is already
starting, of the layer of sand 4, the layer of ballast 5 is
applied. The average grain size k.sub.ballast of the ballast in the
case of the present embodiment lies in a range between 5 to 16 mm,
with the average size of the undersize particles amounting to 5 mm.
Uniform properties are obtained with this narrow grain-size range.
Here as well the ballast is mixed with binding material in order to
apply the mixture as uniformly as possible to the layer of sand 4.
Subsequently, the layer of ballast 5 is compacted with a mechanical
vibrator. The layer of ballast 5 then has an average layer
thickness d.sub.s, of approximately 500 mm.
[0043] Finally, there follows the build-up of the open-pore
superstructure 6 that is visible in the finished state. In the
first instance, binding material in a quantity of 150 g/cm.sup.2 is
sprayed into the layer of ballast 5 that supports the
superstructure 6 in order to achieve a firmer connection between
the superstructure and the substructure 6 and 2 respectively. The
depth of penetration of the binding material amounts to
approximately 150 mm. Even before the binding material hardens, a
layer of mineral aggregates is applied.
[0044] Here as well this is a mixture of mineral aggregates that is
mixed with binding material and is applied in the still deformable
state. The aggregates that come into consideration are selected
from quartzite, granite, basalt and quartz, with coloured granite
being used in the exemplary embodiment that is being described. The
average size of the granite grain lies in the range between 2 and 5
mm. The grain-size distribution is defined according to DIN 66145
with a parameter of at least 9 and whilst disregarding 1% oversize
and undersize particles in each case.
[0045] After the mixture has been applied, this is compacted with a
roller and smoothed with a bladed smoothing screed. Compacting is
preferably effected with a contact pressure of 10 to 50 N/cm.sup.2.
The superstructure after compacting has a layer thickness d.sub.o
of 50 mm. After compacting, the superstructure is hardened. The
ground covering can then be loaded.
[0046] Basically, before applying a layer to a layer that lies
underneath it is not necessary for the layer that lies underneath
to harden. On the contrary, application to a layer that has not yet
hardened results in better connection of the layers one with the
other.
[0047] An alternative embodiment of the ground covering 1 in
accordance with the invention that can be loaded to a greater
extent as a result of an additional layer of sand 4' is shown in
FIG. 2. The additional layer of sand 4' is applied to the layer of
ballast 5 and like the layer of sand 4 on the substratum side is
also stabilized with binding material. For better adhesion, binding
material is sprayed into the layer of ballast 5 before the layer of
sand 4' is applied. After compacting, the build-up of the
superstructure 6 is effected in the same way as described for the
embodiment in accordance with FIG. 1.
List of Reference Numerals
[0048] 1 Ground covering [0049] 2 Substructure [0050] 3 Substratum
[0051] 4, 4' Layer of sand [0052] 5 Layer of ballast [0053] 6
Superstructure
* * * * *