U.S. patent number RE48,052 [Application Number 16/168,400] was granted by the patent office on 2020-06-16 for method of embedding photocatalytic titanium dioxide in concrete structures to reduce pollutants via photocatalytic reactions.
This patent grant is currently assigned to Pavement Technology, Inc.. The grantee listed for this patent is Pavement Technology, Inc.. Invention is credited to Colin Durante, Craig Higgins.
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United States Patent |
RE48,052 |
Durante , et al. |
June 16, 2020 |
Method of embedding photocatalytic titanium dioxide in concrete
structures to reduce pollutants via photocatalytic reactions
Abstract
Methods for embedding photocatalytic titanium dioxide in
concrete surfaces to reduce pollutants via photocatalytic reactions
are provided herein. One method includes applying an amount of
concrete treatment compound to an upper surface of the concrete,
the concrete treatment compound comprising a mixture of a liquid
carrier compound with a titanium dioxide (TiO.sub.2)
photocatalyst.
Inventors: |
Durante; Colin (Mansfield,
OH), Higgins; Craig (San Diego, CA) |
Applicant: |
Name |
City |
State |
Country |
Type |
Pavement Technology, Inc. |
Westlake |
OH |
US |
|
|
Assignee: |
Pavement Technology, Inc.
(Westlake, OH)
|
Family
ID: |
51528219 |
Appl.
No.: |
16/168,400 |
Filed: |
October 23, 2018 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
|
|
61780626 |
Mar 13, 2013 |
|
|
|
Reissue of: |
14207341 |
Mar 12, 2014 |
9493378 |
Nov 15, 2016 |
|
|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
C04B
41/5089 (20130101); C04B 41/65 (20130101); C04B
41/5041 (20130101); C04B 41/5089 (20130101); B01J
35/004 (20130101); B01J 21/063 (20130101); B01J
35/004 (20130101); C04B 41/5041 (20130101); C04B
41/009 (20130101); C04B 41/65 (20130101); B01J
21/063 (20130101); C04B 41/009 (20130101); C04B
41/009 (20130101); C04B 41/009 (20130101); C04B
28/02 (20130101); C04B 28/02 (20130101); C04B
41/5089 (20130101); C04B 41/5089 (20130101); C04B
41/4539 (20130101); C04B 41/4539 (20130101); C04B
41/4549 (20130101); C04B 41/4549 (20130101); C04B
41/457 (20130101); C04B 41/457 (20130101); C04B
41/5041 (20130101); C04B 41/5041 (20130101); C04B
41/4539 (20130101); C04B 41/4539 (20130101); C04B
41/4549 (20130101); C04B 41/4549 (20130101); C04B
41/457 (20130101); C04B 41/457 (20130101); C04B
2111/00827 (20130101); C04B 2111/00827 (20130101) |
Current International
Class: |
C04B
41/50 (20060101); B01J 35/00 (20060101); B01J
21/06 (20060101); C04B 41/00 (20060101); C04B
41/65 (20060101) |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
Other References
Office Action mailed Feb. 8, 2016 in Canadian Patent Application
No. 2845945 filed Mar. 13, 2014. cited by applicant.
|
Primary Examiner: Torres Velazquez; Norca L.
Attorney, Agent or Firm: Kline; Keith The Kline Law Firm
PC
Parent Case Text
CROSS-REFERENCE TO RELATED APPLICATIONS
.[.This patent application claims the priority benefit of U.S.
provisional patent application No. 61/780,626 filed on Mar. 13,
2013, the disclosure of which is incorporated by reference herein
in its entirety..]. .Iadd.This patent application is a reissue of
U.S. Pat. No. 9,493,378, originally issued on Nov. 15, 2016, based
on U.S. application Ser. No. 14/207,341, filed Mar. 12, 2014 which
claims the priority benefit of U.S. provisional patent application
No. 61/780,626 filed on Mar. 13, 2013, the disclosure of which is
incorporated by reference herein in its entirety. .Iaddend.
Claims
What is claimed is:
1. A method for treating a concrete structure, the method
comprising: applying an amount of concrete treatment compound to an
upper surface of the concrete, the concrete treatment compound
comprising a mixture of a liquid carrier compound with a titanium
dioxide (TiO.sub.2) photocatalyst, the liquid carrier compound
carrying the TiO.sub.2 photocatalyst into the concrete structure,
wherein the liquid carrier compound penetrates the concrete to a
depth range of approximately an eighth of an inch to approximately
a quarter of an inch, as measured from the upper surface of the
concrete, so as to embed the TiO.sub.2 photocatalyst therein, and
simultaneously seals and hardens the concrete, and fills voids in
the concrete so as to increase resistance of the concrete to
deleterious effects, the application of the concrete treatment
compound to the upper surface of the concrete causing a reduction
of pollutants proximate to the concrete, the pollutants including
nitrogen oxides and volatile organic compounds, the concrete
treatment compound uniformly impregnating the concrete such that
normal wear of the upper surface of the concrete exposes an
underlying photocatalytic reactive layer of the concrete, so that a
pollution-reducing capability of the concrete treatment compound is
self-regenerated.
2. The method according to claim 1, wherein the deleterious effects
include at least one of water damage, chloride ion penetration,
de-icing salts, and freeze/thaw damage.
3. The method according to claim 1, further comprising texturing
the upper surface of the concrete.
4. The method according to claim 1, wherein the TiO.sub.2
photocatalyst comprises TiO.sub.2 nanoparticles that are mixed into
the liquid carrier compound.
5. The method according to claim 4, wherein the TiO.sub.2
nanoparticles are in an anatase powder form.
6. A method, comprising applying a photocatalytic compound and a
liquid carrier compound to concrete, wherein the photocatalytic
compound is capable of uniformly penetrating the concrete down to a
depth of at least an eighth of an inch relative to an upper surface
of the concrete, the application of the photocatalytic compound to
the upper surface of the concrete causing a reduction of pollutants
proximate to the concrete, the pollutants including nitrogen oxides
and volatile organic compounds, the photocatalytic compound
uniformly penetrating the concrete such that normal wear of the
upper surface of the concrete exposes an underlying photocatalytic
reactive layer of the concrete, so that a pollution-reducing
capability of the photocatalytic compound is self-regenerated; and
the liquid carrier compound is selected such that it simultaneously
seals and hardens the concrete and fills voids in the concrete so
as to increase resistance of the concrete to deleterious
effects.
7. The method according to claim 6, wherein selecting the liquid
carrier compound further comprises selecting a first type of
carrier liquid if the concrete is fully cured and selecting a
second type of carrier liquid if the concrete is not fully
cured.
8. The method according to claim 7, further comprising calculating
an amount of TiO.sub.2 nanoparticles that is necessary to ensure
that the concrete is penetrated and embedded with photocatalytic
material to a sufficient depth.
9. A method, comprising applying a photocatalytic compound and a
liquid carrier compound to concrete, wherein the photocatalytic
compound uniformly penetrates the concrete to a depth of at least
an eighth of an inch relative to an upper surface of the concrete,
the liquid carrier compound including a resurfacing compound that
is applied to the concrete using a squeegee, the application of the
photocatalytic compound to the upper surface of the concrete
causing a reduction of pollutants proximate to the concrete, the
pollutants including nitrogen oxides and volatile organic
compounds, the photocatalytic compound uniformly penetrating the
concrete such that normal wear of the upper surface of the concrete
exposes an underlying photocatalytic reactive layer of the
concrete, so that a pollution-reducing capability of the
photocatalytic compound is self-regenerated.
10. The method according to claim 9, further comprising selecting
the liquid carrier compound such that it is configured to
simultaneously seal and harden the concrete and fills voids in the
concrete so as to increase resistance of the concrete to
deleterious effects.
11. The method according to claim 10, wherein selecting the liquid
carrier compound further comprises selecting a first type of
carrier liquid if the concrete is fully cured and selecting a
second type of carrier liquid if the concrete is not fully
cured.
12. The method according to claim 11, further comprising
calculating an amount of TiO.sub.2 nanoparticles that is necessary
to ensure that the concrete is penetrated and embedded with
photocatalytic material to a sufficient depth.
Description
FIELD OF THE INVENTION
The present invention relates primarily to concrete road
construction, although it can apply to any horizontal or vertical
concrete structures. It is a method of impregnating the concrete
with a photocatalytic titanium dioxide catalyst that reacts with
nitrogen oxides and other pollutants to chemically alter them into
non-hazardous or less hazardous materials through photocatalytic
oxidation (PCO) and/or reduction reaction.
SUMMARY
In some embodiments, the present technology is directed to a method
that includes applying an amount of concrete treatment compound to
an upper surface of the concrete, the concrete treatment compound
comprising a mixture of a liquid carrier compound with a titanium
dioxide (TiO.sub.2) photocatalyst.
In some embodiments, the present technology is directed to a method
that includes applying a photocatalytic compound to concrete,
wherein the photocatalytic compound is capable of uniformly
penetrating the concrete down to a depth of at least an eighth of
an inch relative to an upper surface of the concrete.
In some embodiments, the present technology is directed to a
concrete treatment compound comprising an amount of a carrier
liquid mixed with an amount of a photocatalyst, wherein the carrier
liquid is capable of penetrating concrete down to a depth of at
least an eighth of an inch relative to an upper surface of the
concrete.
BRIEF DESCRIPTION OF THE DRAWINGS
The accompanying drawings, where like reference numerals refer to
identical or functionally similar elements throughout the separate
views, together with the detailed description below, are
incorporated in and form part of the specification, and serve to
further illustrate embodiments of concepts that are included in the
claimed disclosure, and explain various principles and advantages
of those embodiments.
The methods and systems disclosed herein have been represented
where appropriate by conventional symbols in the drawings, showing
only those specific details that are pertinent to understanding the
embodiments of the present disclosure so as not to obscure the
disclosure with details that will be readily apparent to those of
ordinary skill in the art having the benefit of the description
herein.
FIG. 1 is a flowchart of an exemplary method of treating concrete
to reduce the production of nitrogen oxides (NO.sub.x), volatile
organic compounds (VOC), and other pollutants .[.by.]. .Iadd.near
the surface of .Iaddend.the concrete;
FIG. 2 is a method for preparing the concrete treatment compound
that is to be applied to the concrete; and
FIG. 3 is a cross sectional view of a treated section of
concrete.
DETAILED DESCRIPTION
While this technology is susceptible of embodiment in many
different forms, there is shown in the drawings and will herein be
described in detail several specific embodiments with the
understanding that the present disclosure is to be considered as an
exemplification of the principles of the technology and is not
intended to limit the technology to the embodiments
illustrated.
The terminology used herein is for the purpose of describing
particular embodiments only and is not intended to be limiting of
the invention. As used herein, the singular forms "a", "an" and
"the" are intended to include the plural forms as well, unless the
context clearly indicates otherwise. It will be further understood
that the terms "comprises" and/or "comprising," when used in this
specification, specify the presence of stated features, integers,
steps, operations, elements, and/or components, but do not preclude
the presence or addition of one or more other features, integers,
steps, operations, elements, components, and/or groups thereof.
It will be understood that like or analogous elements and/or
components, referred to herein, may be identified throughout the
drawings with like reference characters. It will be further
understood that several of the figures are merely schematic
representations of the present technology. As such, some of the
components may have been distorted from their actual scale for
pictorial clarity.
The present technology is embodied in some instances as a method of
embedding photocatalytic TiO.sub.2 nanoparticles into horizontal
and vertical concrete structures that are either already in place
or in the process of curing. It is envisioned that the process may
be used for all concrete structures, but particularly those in
close proximity to roads and highways. The introduction of
TiO.sub.2 is by impregnation into concrete structures using
specialized multi-purpose concrete curing and preservation
products, hereinafter referred to as a "concrete treatment
compound".
An advantage of the present technology is that it provides a method
of introducing photocatalytic oxidation technology into existing
concrete structures, without the prohibitive cost and disruption of
removing said structures and replacing them with new concrete.
Another advantage of the present technology is that it provides a
method of economically introducing photocatalytic oxidation
technology into just the upper layers of freshly placed concrete,
eliminating the prohibitive cost of mixing expensive titanium
dioxide into the entire concrete mix.
Another advantage of the present technology is that the concrete
treatment compounds uniformly impregnate the concrete at depths
great enough that normal wear of the upper surfaces will expose
underlying photocatalytic reactive layers to the surface, so that
the pollution-reducing capability is self-regenerated (e.g.,
remains consistent or viable) throughout the lifespan of the
concrete structure.
Another advantage of the present technology is that the concrete
treatment compounds simultaneously seal and harden the concrete and
fill voids in its structure to increase resistance to water damage,
chloride ion penetration, de-icing salts, and freeze/thaw damage.
Sealing of the concrete may also improve long-term photocatalytic
performance. Indeed, residual salt and water build-up on
traditional concrete structures can interfere with photocatalytic
oxidation. These protective effects are provided by a liquid
carrier compound, into which the TiO.sub.2 is mixed.
The present technology contemplates a method of embedding
photocatalytic TiO.sub.2 nanoparticles, via delivery using concrete
treatment compounds, into horizontal and/or vertical concrete
structures that are either already in place or in the process of
curing. It is envisioned that the process may be used for all
concrete structures, but particularly roads and highways and
structures in nearby proximity to them. The introduction of
TiO.sub.2 is by impregnation into concrete structures using
specialized concrete treatment compounds, resulting in the creation
of a photocatalytic reactive layer at the surface of the structure
and a uniform distribution of TiO.sub.2 nanoparticles in the upper
layers of the concrete to depths as great as one half (0.5) inches.
In some embodiments, the impregnation or embedding of the
nanoparticles is uniform and extends to a depth of between
approximately one quarter of an inch to approximately one half of
an inch relative to an upper surface of the concrete.
For context, TiO.sub.2 is an inorganic pigment and semiconductor
material that when exposed to ultraviolet (UV) radiation, as from
sunlight, expels an electron from the valence band to the
conduction band, leaving behind a positively charged hole. In the
presence of water, as in atmospheric humidity, these positively
charged holes create hydroxyl radicals as shown:
OH.sup.-+h.sup.+.fwdarw.*OH.
The hydroxyl radicals in turn oxidize nitrogen oxides as follows:
NO+*OH.fwdarw.NO.sub.2+H.sup.+
NO.sub.2+*OH.fwdarw.NO.sub.3.sup.-+H.sup.+.
Other reduction effects occur with volatile organic compounds (VOC)
and some other pollutants. Since TiO.sub.2 functions as a catalyst
and is not consumed in the reaction, the photocatalytic effect
continues. If the TiO.sub.2 is in place at the surface of concrete,
it removes a significant quantity of NO.sub.x and VOCs from the
environment nearest their source. If TiO.sub.2 is uniformly
impregnated into the concrete to a given depth the
pollution-reducing capability of the concrete will automatically
and continuously self-regenerate as the surface layers are
subjected to the normal wear of traffic and other environmental
factors.
Other reduction effect occurs with volatile organic compounds (VOC)
and some other pollutants. Since the TiO.sub.2 functions as a
catalyst and is not consumed in the reaction, the photocatalytic
effect can continue. If the TiO.sub.2 is in place at the surface of
a concrete roadway or other concrete structure in close proximity
to the roadway, it removes a significant quantity of NO.sub.x and
VOCs from the environment near their source. If TiO.sub.2 is
uniformly impregnated into the concrete at depth using a liquid
carrier compound, the pollution-reducing capability of the concrete
will automatically and continuously self-regenerate as the surface
layers are subjected to the normal wear of traffic and other
environmental factors.
Traditional methods of NO.sub.x reduction (e.g., catalytic
converter reduction of motor vehicle emissions) have reached a
point of diminishing returns in terms of cost effectiveness,
resulting in the need for new and innovative methods of pollutant
reduction. A method of reducing these pollutants may be the use of
photocatalytic titanium dioxide blended into concrete paving
mixtures at the time of construction. This method has not seen
widespread acceptance or practical implementation yet for a number
of reasons.
One key disadvantage of the method described above is its
limitation to usage in freshly placed concrete surfaces, reducing
its economic viability for existing roadbeds that are structurally
sound, which comprise a large percentage of the roadbeds and
structures that would be most subject to violating the forthcoming
Environmental Protection Agency (EPA) guidelines. The tremendous
cost that would be created by replacing these roadbeds and
structures with new concrete would be prohibitive, both in terms of
dollar cost and user delays.
The present technology impregnates the concrete with TiO.sub.2 by
applying specialized proprietary penetrating liquid carriers to the
surface of a concrete structure. These carriers are designed and
proven to carry chemicals into concrete. The TiO.sub.2 is blended
into the liquid carriers at a proportion that will result in a
uniform distribution of TiO.sub.2 nanoparticles throughout the
upper one-half (0.5) inch layer of the concrete structure, or to
other depths according to road or structure design requirements. As
mentioned above, the combination of liquid carrier compound and
TiO.sub.2 is referred to as a concrete treatment compound.
Examples of liquid carrier compounds that may be used for this
purpose are Litho1000Ti (for existing, cured concrete) manufactured
by Pavement Technology, Inc. and Lithium Cure Ti (for new concrete
that is in the curing process) manufactured by Sinak
Corporation.
These carrier compounds have the added benefit of sealing and
hardening the concrete and filling voids in its structure to
increase resistance to water damage, chloride ion penetration,
de-icing salts, and freeze/thaw damage. In some embodiments, an
anatase powder form of TiO.sub.2 nanoparticles at a specific
concentration is combined with the liquid carrier that will result
in TiO.sub.2 being delivered at the designed rate of application
for the impregnated region. To be sure, other penetrating liquid
carriers and/or forms of TiO.sub.2, other semiconductors or
inorganic pigments that are photocatalytic and alternate
concentration levels, can be employed as deemed suitable.
In some embodiments the concrete treatment compound comprising the
TiO.sub.2 additive (or other photocatalytic compound) is sprayed or
otherwise applied to horizontal road surfaces by a sprayer
applicator with a spray bar of variable length utilizing industry
standard nozzles. The application rate is controlled by a
computerized flow manager, which allows the carrier compound to be
precisely applied to the road surface. Once the flow rate computer
has been set to the desired application rate, the application of
the carrier compound is very accurate due to the computer control
of the flow, regardless of travel speed variations of the sprayer.
On vertical surfaces, or other surfaces inaccessible to a sprayer
applicator with spray bar, the compound can be applied by hand
spraying with a wand, or any other suitable means of application
that maintains the required accuracy.
If conditions in a given application dictate that a horizontal
concrete surface requires texturing for safety, adhesion or other
reasons, abrasive media application methods will be employed prior
to spray application of the liquid carrier compounds. Exemplary
methods are the Skidabrader process, conventional shot blasting,
diamond grinding, water blasting, and the like.
In some embodiments, if the concrete surface is damaged or the
surface has an unacceptable slip coefficient (e.g., a surface
texture that is likely to cause an individual to slip and fall on
the surface) the surface to be treated may be textured using the
aforementioned abrasive process, or repaired if necessary.
Additionally, the concrete treatment compounds of the present
technology can be applied to a concrete surface without first
priming the surface, which is often required for concrete treatment
processes such as painting or sealing.
As mentioned above, the amount concrete treatment compound (e.g.,
carrier compound plus photocatalytic material) that is applied to a
concrete surface should be enough to penetrate the concrete down to
between a depth range of approximately an eighth of an inch to
approximately a half of an inch, inclusive. Further, a
concentration of photocatalytic material within the liquid carrier
compound should be sufficient to achieve a desired concentration of
the photocatalytic material within the concrete surface. This
process of delivering concrete treatment compounds is referred to
as distributive embedding.
The depth to which the concrete treatment compound should be
distributively embedded may depend upon a variety of factors such
as the composition and size of the aggregate used to create the
concrete or the binder used to hold the aggregate together. By
example, the photocatalytic material of the concrete treatment
compounds may only need to penetrate up to one quarter of an inch
for asphalt cement that includes an aggregate that is small and
tightly packed such that it resists wear off, whereas a cement that
is known to wear off quickly may require photocatalytic material to
be embedded further into the concrete to account for additional
wear. Other factors may include expected or average traffic or use
patterns that may predict wear off rates, as well as weather
information. Other factors that would be apparent to one of
ordinary skill in the art are also likewise contemplated for
use.
Thus, in some instances, it is required to calculate an amount of
concrete treatment compound of the present technology, which will
be required to penetrate the concrete surface down to a sufficient
depth relative to an upper surface of the concrete surface. The
examples of factors that affect wear off may be used as a part of
this calculation. For example, if it is determined that based upon
concrete composition and traffic pattern that an average wear off
of 0.005 inches per year is expected, and the lifespan of the
concrete surface is forty years, the concrete treatment compound
should be applied so as to penetrate to a depth of at least one
quarter of an inch, as the expected wear off would be 0.2 (two
tenths) inches over the forty years.
FIG. 1 is a flowchart of an exemplary method of treating concrete
to reduce nitrogen oxides (NO.sub.x), volatile organic compounds
(VOC), and other pollutants.
The method optionally includes preparing 105 the concrete, if
necessary, to remove surface contaminates to ensure that the
concrete treatment compound can adhere to and penetrate the
concrete to the depth required.
In some embodiments, the method optionally includes texturing 110
the upper surface of the concrete. Again, this includes, for
example, using an abrasive technique to prepare the surface of the
concrete.
The method also comprises applying 115 an amount of concrete
treatment compound to an upper surface of the concrete. As
mentioned above, the concrete treatment compound comprises a
mixture of a liquid carrier compound with a titanium dioxide
(TiO.sub.2) photocatalyst. In some instances, the TiO.sub.2
photocatalyst is an anatase powder form of TiO.sub.2 nanoparticles
that is mixed into a liquid carrier compound. The liquid carrier
compound may include any liquid that can seal and harden concrete
and fills voids therein to increase resistance of the concrete to
water damage, chloride ion penetration, de-icing salts, freeze/thaw
damage, and other deleterious effects.
The method includes allowing 120 the treated concrete to dry for a
period of time.
FIG. 2 is a method for preparing the concrete treatment compound
that includes calculating 205 an amount of concrete treatment
compound that is necessary to ensure that the concrete is
penetrated and embedded with photocatalytic material to a
sufficient depth.
The method also includes selecting 210 a photocatalytic material
for the concrete treatment compound that is capable of reducing an
amount of nitrogen oxides (NO.sub.x) and volatile organic compounds
(VOC).
The method also includes selecting 215 a carrier liquid for the
concrete treatment compound that is capable of penetrating and
delivering the photocatalytic material to a sufficient depth of the
concrete. In some embodiments, the method includes mixing 220 the
concrete treatment compound by combining a liquid carrier compound
with an amount of the selected photocatalytic material.
FIG. 3 illustrates an asphalt concrete section 305 that has been
treated with concrete treatment compound 310. The concrete section
305 is shown as having an upper surface 315. The amount of concrete
treatment compound 310 has penetrated down from the upper surface
315 to a depth D. This depth D can range anywhere between at least
an eighth of an inch, down to a quarter of an inch. Other depths
may also be utilized and can vary according to design requirements
and usage.
Other examples of compounds that may be used as carrier liquids
include SurfCrete Ti manufactured by Pavement Technology, Inc., and
RELAY Ti manufactured by Sinak Corporation. One embodiment of the
present technology utilizes an anatase powder form of TiO.sub.2 at
concentrations of 3% to 5% by weight. Other resurfacing compounds
and/or forms of TiO.sub.2, and alternate concentration levels, can
be employed as deemed suitable.
In some embodiments the compound is applied with squeegees to a
concrete surface that has previously been roughened with abrasive
media, such as the Skidabrader process, conventional shot blasting,
diamond grinding, water blasting, and the like. For thicker
applications, the compound is applied in layers, typically nine (9)
mils thick, with each layer being allowed to dry before the next
layer is applied.
While the present technology has been described in connection with
a series of steps, these descriptions are not intended to limit the
scope of the technology to the particular forms set forth herein.
It will be further understood that the methods of the invention are
not necessarily limited to the discrete steps or the order of the
steps described. To the contrary, the present descriptions are
intended to cover such alternatives, modifications, and equivalents
as may be included within the spirit and scope of the invention as
defined by the appended claims and otherwise appreciated by one of
ordinary skill in the art.
* * * * *