Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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SAFETY ROADt~IAY DELINEATOR
EFFECTIVE DURING RATNY NIGHT-TIME DRIVING CONDITTONS
AND METflOD OF MAKING THE SAME
BACKGROUND OF THE INVENTION
Field Of The Invention
The invention generally relates to highway struc Lures
and more specifically to a safety roadway delineator which is
substantially immune from normal wear and reliably exhibits
reflectivity both under dry and rainy night-time weather
conditions and method of making the same.
Description Of The Prior Art
Reflective stripes and other markings have been
provided on highways and highway structures, such as curbs and
median barriers, in order to delineates or identify the boundaries
of a highway or to divide lanes on a mufti-lane highway. One of
the major problems with suc h delineators has been their
visibility under different driving or weather conditions, on the
one hand,' and the durability of such markings or stripes, on the
other hand.
While such delineators function properly and
efficiently under ideal driving or weather conditions,
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their usefulness frequently deteriorates during inclement
weather, particularly when it rains. ~Jnder such adverse
conditions, the delineators are frequently not clearly
visible and this poses a danger or hazard to those using
the highway or road. The problem and the need for a ~
solution have been discussed by transportation engineers
and others who are involved with the design, construction
and maintenance of highways. See, for example, "ITE
Hearing Record--Performance Standards For
Retroreflectivity Of Traffic Control Devices°', Institute
of Transportation Engineers, August 21, 1985; and
"Operation, Safety and Maintenance Of Transportation
Facilities", Transportation Research Circular No. 306,
June, 1986, Transportation Research Hoard, National
Research Council. In the foregoing publications, there is
discussed the need to improve markings for highways,
particularly under wet or rainy night-time driving
conditions.
With the introduction of relatively durable
paints and applied plastics, along with the advent of
retroreflective glass microspheres, a partial solution to
night-time traffic delineation has become available.
However, these techniques still have certain drawbacks.
For example, reflective markers or delineators which are
exposed to normal traffic will wear down or be adversely effecte,
by inclement weather, road salt and corrosive and chemical
attack, and mechanical snow removal equipment. Additionally,
during wet or rainy weather driving conditions, water causes
the refractive and reflective light indices to change for
both reflective beads and the base materials. In some cases,
the wetting of such reflective materials cause the total
visual disappearance of the demarcation elements. Such
visual deviation is due~to a mirror" effect of the
headlights impinging upon the water on the reflective
material instead of directly on the reflective material .
itself. All of these disadvantages are true not only of
roadways, but a:Lso curbs, median dividers, and other traffic
routing devices.
Numerous solutions have been proposed for achieving
the goal of providing a reliable highway delineator which
functions satisfactorily both during ideal as well as during
inclement weather conditions. For example, in U.S. Patent
No. 2,345,644, issued to Weber on April 4, 19x4, there is
described a light reflecting sign or marker which utilizes a
Portland cement base poured on site and relatively large
glass reflective beads are imbedded in a pre-cast panel of
white Portland cement which is imbedded in the cement curb.
eowever, the panel is disposed at the~exterior surface of the
cement base which is exposed to the vehicular traffic. The
glass beads, in fact, project beyond the surface and,
therefore, are susceptible to contact with vehicles and,
therefore, the probability that such glass reflective beads
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will be dislodged is substantial.
In L1.S. .Patent No. 3,203,327, issued to Daley on
August 31, 1965, a cast metallstreet curb is disclosed which
includes vertical ribs or recesses,. Although the patentee
3oes not showreflective material within sucks recesses, he
does mention that it is possible to provide paint or a
similar finish in order to enhance the visibility of the curb
to motorists at night. However, Daley does not teach or
suggest the use of elongate horizontal delineators which run
generally parallel to the road and which are recessed and
provided with retroreflective materials in order to enhance
the amount of reflection under adverse weather conditions.
U.S. Patent No. 4,000,882, issued to Penton on
January 4, 1977, discloses a contrasting marker panel for
highway guardrails. Penton intends, however, to utilize his
invention with the most commonly used form of continuous
guardrail which is formed of sheet iron or steel. Penton
utilizes a marker panel which is receivable within the trough
of the guardrail and covered with a plastic film. Penton
suggests that such plastic film may sometimes be
reflectorized and also suggests that a reflector or
reflectors may, in certain instances, be mounted within the
trough so as to be exposed outwardly of the guardrail
recess.
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The Penton marker panel is not, however, suitable
for use in connection with other~highway safety structures,
particularly those made of cast-in-place concrete or pre-cast
elements.
SOMMARY OF T9E INVENTION
One object of the invention is to provide a roadway
delineator which overcomes the disadvantages inherent in
prior art reflective markers and delineators.
It is another object of the present invention to
provide a roadway delineator which is simple in construction
and inexpensive to manufacture.
It is still another object of the present invention
to provide a roadway delineator which is substantially immune
from normal wear.
It is yet another object of the invention to
grovide a roadway delineator of the type under discussion
which will provide reliable reflectivity and guidance for
vehicular traffic in rain and night-time conditions.
It is a further object of the invention to provide
a roadway delineator which can be.usea in a variety of
applications and with different roadway structures.
It is still a further object of the invention to
provide a roadway delineator which has a great deal of
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flexibility and can,be ~ncorpbrated into highway structures
both on'site or in.pre-cast structures which can be brought
to the site. ' .
It is an additional object of the inven~fon to
provide a roadway delineator which can be used with a variety
of different reflecting materials, and particularly with
retroreflective materials.
.In order to achieve the above objects, as well as
others which will become apparent hereafter a safety roadway
delineator in accordance with the present invention comprises
an elongate roadway member forming a barrier which extends
along and at least partially defines the roadway. The
roadway member has an exterior surface which faces the
roadway and is exposed to the roadway traffic. Said roadway
member is provided with a generally elongate marker surface
recessed in relation to said exterior surface. Said marker
surface extends along the length direction of said roadway
member-and is inclined in relation to the horizontal to cause
water run-off. Reflection means is provided which is applied
to said recessed marker surface for at least partially
reflecting incident light in the directiqn of the source of
inafdent light on the roadway. In this manner~ said roadway
member forms a substantially continuous reflective delineator
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which is protectec3~fr.om normal wear and reliably exhibits
reflectivity both under dry and rainy weather coni3iti~ns.
Advantageously, the safety roadway delineator in
accordance with the invention utilizes a retroreflective
material, such as glass microspheres which are set into a
very durable material whose adherence depends both.on a
chemical as well as a mechanical bond, The base material
into which the reflective material is set advantageously
exhibits outstanding strength characteristics as well as
being chemical and weather resistant. As noted, further
protection from physical damage to the microspheres is
attained by recessing the implant so as not to have the
retroreflective area within the proximity o~ normal wear due
to scraping tires, wheel rims, road sweeping vehicles or snow
removal equipment.
An important feature of the present invention is
that the recessed surface to which the reflective material is
applied~is vertical or inclined in relation to the horizontal
to cause water run-off and insure that the reflective
material is not subjected t~ the "mirror" effect and a
deterioration of the reflective characteristics due to rain
or wet conditions, this insuring continued safe night-time
driving during inclement or rainy weather conditions.
The invention provides continuous edge, or
island, or bridge demarcation and is helpful to minimize
depth perception difficulties encountered with other prior
approaches.
SRIEF DESCRIl~TION OF TfiE DRAWINGS
For a better understanding of the invention
together with other and further objects, features and
advantages thereof, as well as other characteristics of
various embodiments thereof, reference is had to the
fallowing description taken in conjunction with the
accompanying drawings in which:
FIG. 1 is a perspective view of a pre-cast
reflective polymer concrete curb form in accordance with
the present invention, partially broken away to illustrate
how the pre-cast concrete section is attached to a cast-
in-place concrete structures
FIG. lA is an enlarged cross-sectional view of
the curb shown in FIG. 1, taken along line lA-lA:
FIG. 1B is an enlarged side elevational view of
one glass bead or microsphere, showing how the same are
embedded within a binding matrix in accordance with the
invention;
FIGS. 2-S illustrate different angles of
inclination in relation to the horizontal of the recessed
marker surfaces, each of which provides desired water run-
off;
FIGS. 6-10 illustrate different roadway members
made of cast-in-place concrete arid provided with pre-cast
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facing panels formed with the recessed marker surfaces,
all of the elongate marker surfaces being vertical with
the exception of the one shown in FIG. 8, which is
inclined at approximately 45° to the horizontal. FIG. 10
also illustrates the use of two pre-cast members spaced
one above the other on the concrete road structure to'
provide two reflective roadway delineators one above the
other;
FIGS. 11-15 illustrate roadway members similar
to those shown in FIGS. 6-10, respectively, but showing
the elongate marker surfaces formed directly in the cast-
in-place concrete roadway members and not on separate pre-
cast elements or facing panels;
FIG. 16 is a front elevational view of typical
low and high bench panels used :in tunnel constructions,
illustrating the manner in which the present invention is
incorporated in pre-cast polymer concrete members which
are attached to cast-in-place concrete structures;
FIG. 17 is similar to FIG. 16, except that the
elongate marker surfaces are formed directly in the cast-
in-place concrete;
FIG. 18 is a front elevation view, in section,
of a typical construction of a bridge rail or pedestrian
walkway, showing how a curb facing in accordance with the
present invention may be attached to the cast-in-place
concrete curb;
FIG. 19 is similar to FIG. 18, except that the
elongate marker surface is provided and recessed directly
in the cast-in-place concrete structure.
to
1~IG. 20 is a perspective view of a two-sided median
barrier of the type used as a divider between lanes, showing
upper and lower elongate recessed marker surfaces on each
side of the median barrier and also shown filled with
concrete;
FIG. 21 is a perspective view of a one-sided median
barrier of the type which faces a single lane, shown abutting
against a concrete wall, and showing two elongate recessed
marker surfaces, the lower one of which is vertical, and the
higher one of which is inclined at an angle in relation to
the horizontal; and
FIGS. 22 and 23 are similar to FIGS. 2o and 21,
except that the recessed elongate marker surfaces are formed
directly in cast-in-place concrete.
Description of the Preferred Embodiments
Referring now specifically to the figures, in which
identical or similar parts are designated by the same
reference numerals throughout, and first referring to FIG. 1,
a roadway member in accordance with the present invention is
generally designated by reference numeral 1U.
The roadway member 1D forms a barrier which extends
along and at least partially defines the roadway 12.
Specifically, the roadway member 10 shown in F'IG. 1 is a
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curb which can be anade in any known or conventional way and
is shown is FIG. ~ to be formed of cast-in-place regular
concrete 14. In accordance with the present invention, there
is provided a pre-cast member or element i6 which is
a
attached to the 'concrete member 14 by means of anchors 18 or
in any other &cnown or conventional manner.
As will become apparent hereafter, the specific
material from which the element 16 is formed is not critical.
However, it is presently preferred that the element or member
16 be of reinforced pre-cast polymer concrete. It has been
found that polymer concrete is particularly suitable for the
intended purpose. Polymer concrete as a hybrid product which
exhibits improved performance characteristics over regular
concrete or cementitious materials. Polymer coneretes are
generally lighter in weight, exhibit increased tensile and
compresive strength, and generally have a higher resistance
to moisture and other corrosive elements. Polymer concrete
does not contain cement and is made up of various binders,
such as polyesters of numerous types of long chain monomers,
epoxies, anethyl methacrylates, urethanes and vinylesters.
Because the viscosities of these binders differ, the amounts,
sues and proportions of the fill may vary with each
particular polymer. Thus,~determining which binder to use is
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usually based on strength desired and cost considerations.
Different polymer concretes can be used in connection with
the present invention, with different degrees of advantage.
Polymer concrete produced by Transpo Industries,
Inc., Castek Division, has been successfully used to praduce
the pre-cast polymer concrete roadway delineators in
accordance with the invention. Polymer coneretes are
discussed in a brochure entitled °Polymer Concrete--The State
Of the Art~, an information bulletin from Transpo Industries,
Inc., the Assignee of the subject application.
Still referring to FIG. 1, the roadway member 10 is
an elongate member the length direction of which extends
substantially parallel to the roadway 12. The pre-cast
polymer concrete member or~facing panel 16 has an exterior
surface 20 which faces the roadway 12 and is exposed to
roadway traffic. A generally elongate marker surface 22 is
provided on the facing panel 16 recessed in relation to the
exterior surface 20. The marker surface 22 preferably forms
an elongate line which extends along the length direction of
the facing panel 16 and is inclined in relation to the
horixontal to cause water run-off. In the roadway member 10,
the recessed marker surface 22 is in a vertical plane or
inclined 90' in relation ~o the horizontal. This
configuration, clearly, provides maximum water run-off.
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However, smaller angles can be used with similar advantage.
Although the recessed marker surface 22 is shown as a
continuous line in FIG. 1, as well as in the remaining
figures, it should be clear that the present invention
also contemplates a continuous marker surface which is,
intermittently or periodically interrupted to form an
elongate discontinuous reflective surface.
An important feature of the invention is the
provision of reflection means applied to the recessed
marker surface 22 for at least partially reflecting
incident light in the direction of the source of the
incident :light on the roadway. Although any one of
numerous reflective materials may be used, it is presently
preferred that retroreflective materials be applied to the
recessed marker surface 22, such as reflective glass beads
2~. Prismatic materials (sheeting) can also be used to
provide retroreflectivity. Glass beads, because of their
spherical configuration, have a much larger range of
entrance angles for which retroreflectivity will be
exhibited. The use of retroreflective materials and,
glass beads, in particular, are well known to those
skilled in the art.
However, the ability to resist dislodging
forces, (e. g. abrasion, freeze thaw cycling, expansion
coefficient differences and lack of adhering gualities--
either adhesive, cohesive or mechanical) is enhanced as a
result of the method used to attach the microspheres to
the marker surface 22 as will now be described.
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In this connection, the ~ollowing definitions
come into play:
(a) Adhesive Adhesion: the ability to stick
together; the force that holds unlike molecules of
substances together. Examples--tape, glue, caulking; ,
(b) Cohesive Adhesion: the force which unites
arid cleaves together molecules of like or similar
materials. Examples--polyester on polyester, caulking
onto caulking, etc.;
(c) Mechanical Adhesion: action whereby one
material stays in intimate contact with another because of
a physical constraint or blocking action. Example: a
sphere bueied more than 50% in another solid where no
sticking takes place but.wherein the base surrounds the
sphere to the depth of its embedment. . .
(d) Coupling: to link or connect intimately
through a chemical reaction of dissimilar molecules,
especially between organic and inorganic materials.
Example--polyester to silica sand, polyester to
fiberglass, etc.
Referring to Figs. lA and 1B, the placement,
retention and durability of glass retroreflective beads
24 into a polyester matrix 25 of the marker surface 22 is
shown. The beads 24 can also be placed into a base of
pigmented epoxy, methyl methacrylate or a combination of
these materials. The ability to make the beads 24 stick
to the matrix and continue the uninterrupted retroflective
CA 02033527 2000-11-09
WH-8203CA - 15 -
quality of the beads in spite of normal and abnormal
conditions thrust upon it is a feature not found in other
devices.
The beads stick 24 to the matrix 25 because of
the adhesive, cohesive and mechanical procedures applied.
Skilled application techniques have been developed to
control proper placement and embedment, working in a
sympathetic reactive organic base.
When a catalyzed polymer liquid base coat having
a thickness "t" gauged to the proportional thickness or
diameter "D" of a reflective bead is applied either to a
cementitious or polymer concrete base wherein a proper
cohesive or adhesive bond is created between this liquid
and the base, a configured area (strip or other shape),
creates a retroreflective device upon the hardening
(setting) of said liquid base.
The microbeads 24 are applied (while the base is
still liquid) into the liquid to the gauged depth of more
than 50~ of the vertical radius thus seating the bead
sphere 24 into the liquid 25 wherein a mechanical bond is
created. Preferrably the microbeads are embedded within
the base coat a depth selected from the range of 51o to 80~
of the average bead diameter.
Further, because of the "silane" coupling
occurring between the bead 24 and the liquid base 25 (upon
hardening) an actual coupling bond is created, thus giving
additional retention strength to the "union".
A further process can be added by recessing the
area to be retroreflectorized. This gives protection from
scuffing and abrasion.
is
As can be determined, by the use of these
foregoing techniques, the strip or other configuration of
the beads does not rely on the cementitious or polymer
concrete structure which is to be retroreflectorized.
The facing panel 26 is shown in FIG. 1 to have a
length 26, a thickness 27, and a height 28, These
dimensions of the facing panel are not critical. For curb
applications, the height of the facing panel 16 can, for
example, be between 12 to 18'° in height and 9-8' in length.
Since highways and
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roads can exend for many miles, a plurality of such facing
panels ~6, each of which is pre-cast, may be arranged
end-to-end to each other to form a substantially continuous
barrier, and the recessed marker surfaces aligned with each
other to form a substantially continuous reflective
delineator. Tn the case of cast-in-place concrete versions
of the invention, it is possible, in theory, to use a
continuous roadway member extending along the entire length
of the highway or road.
As above noted, the elongate recessed marker
surface 22 is inclined in relation to the horizontal to cause
water run-off to prevent the "mirror" effect and a
deterioration of the retroreflective properties of the
reflecting material. In order to eliminate or minimize this
"mirror" effect, it is imperative that any rain or water
which comes into contact with the reflective material be
prevented from accummulating and covering the reflective
material. Referring to FIGS. 2-5, four different examples
are showy in which the recessed marker surfaces 22a-22d ace
inclined at successively smaller angles ~a- ~ d in
relation to the horizontal. The facing panels 10a-10d are
all effective fn draining the rain or water from the
reflective surfaces. Clearly, the greater the angle in
relation to the horizontal, the more rapid the run-off and,
therefore, the less likely of any appreciable
la
accummulation of water covering the reflective material
during heavy rain. The inclination of the recessed marker
surfaces 22a-22d also has the advantageous feature that water
run-off washes or cleans the reflective surface, such as the
reflective beads, and this self-cleaning action maintains the
reflective surface at optimum or near-optimum reflecting
condition.
Referring to FIGS. 6-10, five typical roadway
structures 10e-t0i are shown, each of which is formed by
cast--in-place concrete to which one or more pre-cast polymer
concrete facing panels 16 are attached each with a recessed
marker surface 22a. In the case of FIG. 10, the roadway
member 10i is provided with an upper facing panel 16a and a
lower facing panel 16b to provide elongate vertically spaced
roadway delineators in accordance with the present invention.
As will be noted from FIGS. 6-10, the present invention is
extremely flexible and .can be used in connection with almost
every roadway member irrespective of size or shape. FIGS.
11-15 are similar to FIGS. 6-10 and illustrate the same types
of roadway members. Sawever, separate facing panels are nat
used in FIGS. 71-15. Instead, the recessed marker surfaces
22a and 22c are formed directly in the cast-in-place concrete
members. This can be done during the molding process for new
installations. To modify an existing installation, any
conventional equipment, such as grinders, can be used to
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remove a thickness of the concrete to produce the recessed
marker surfaces. The roadway structures in FIGS. 10-11 are
designated by references 10e'-90i', which correspond to the
roadway members i0e-10i in FIGS. 6-10.
In FIG. 16, there is shown a tunnel 10j through
which the roadway 12 passes. For purposes of illustration, a
low bench panel 32 is shown with a first reflective surface
22a substantially at the level of the roadway 12, and a
second reflective surface 22a just above the fiest reflective
surface. The positions of the reflective surfaces is not
critical for the purposes of the present invention and their
locations will vary depending on the apglication. In the
case of the high bench panel 34, a first reflective surface
22a is formed in the facing panel 16a in the upper region of
the bench panel 34. A second reflective surface 22a is
formed in the lower facing panel 16b which is substantially
at the level of the roadway 72. In FIG. i7, low bench panel
32' corresponds to the panel 32 in FIG. 16 and the high bench
panel 34' corresponds to the bench panel 34 in FIG. 16. The
tunnel 10k constructions are similar, therefore, to those in
FIG. 16 with the exception that the reflective surfaces are
formed directly in the concrete and separate facing panels
are not utilized.
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Referring to FIGS. 98 and 19, bridge rail and
pedestrian walkways 101 and 101' are shown which are similar
in construction to the curb constructions shown in FIG. 1.
In FIG. 18, a polymer concrete facing panel 16 is utilized,
while in FIG. 19, the reflecting surface 22a is formed
directly in the concrete. Also shown in these figures is an
overlay 36 which is applied to the roadway after the curb
facing panel 16 is attached by means of anchors 18 or other
suitable means to the roadway.
Referring to FIGS, 20 and 21, there are shown
pre-cast polymer concrete median barriers 38 and 40. In FIG.
20, the median barrier 38 is a two-sided median barrier which
can be used as a divider between lanes. Seing pre-cast and
transported to the site of use, the median barrier 38 is
advantageously initially made hollow to reduce its weight and
filled with concrete 14 at the site. The barrier 38 is
provided with an upper marker surface 22e and a lower marker
surface 22f, these being provided on each side of the median
barrier so that similar roadway delineators are visible in
each of the lanes separated by the barrier. In FIG. 21, a
one-sided median barrier 40 is shown which faces only one
lane, and may abut against a concrete wall or the like.
Sere, the median barrier 40 is provided with a lower marker
surface 22f and a slightly higher marker surface 22g which is
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inclined at~an angle less than 90° from the horizontal. It
should be clear that one, two or snore marker surfaces~may be
provided on each roadway member oriented and spaced from each
other in any desired fasteion.
In FIGS. 22 and 23, median barriers 38' and 40' are
shown which are similar to those shown in FIGS. 20 and 21,
respectively, except that the median barriers are formed of
cast-in-place concrete and the recessed marker surfaces are
formed directly in the concrete without the use of separate
facing panels.
While preferred embodiments of the invention have
been shown and described herein, it is obvious that numerous
additions, changes and omissions imay be made in the invention
without departing from the spirit and scope thereof. Thus,
for example, while it is presently preferred that the marker
surfaces be inclined in relation to the horizontal at an
angle of at least 45°, any suitable angle selected for a
particular application may be used.
