AU2014101250A4 - Textured roadmarkings for wet weather visibility and improved skid resistance - Google Patents

Abstract

Roadmarking 1 is disclosed which, when installed in a position of use on pavement 2, includes a plurality of drainage grooves 5 defined between raised faces 4 whereby during rain retro-reflective means embedded in said faces 4 are disposed above a level of surface water on said roadmarking. -7- A' <,N < N << w A N' - < <AN' A N' N' .N' ,"' <N <N' ,N"' ~N - N' -c <(N,>< N' <A >9" <N' A~'NN N' .N N - N' N' N' 'j~N ~ < N' N' 'N 4-- < A <xx- '<[it «> <t< < N' N' N' ~N' N <A < aN N$<N' N' <N' N' A-' 1---~ <<N N' < <N' ~ Ny A A-Ni N< A"'-' < <N' N' V A < « <A < N' 2 __________ __________

Description

COMMONWEALTH OF AUSTRALIA PATENTS ACT 1990 COMPLETE SPECIFICATION INNOVATION PATENT Invention Title: TEXTURED ROADMARKINGS FOR WET WEATHER VISIBILITY AND IMPROVED SKID RESISTANCE The following statement is a full description of this invention including the best method of performing known to me. 1 This invention relates to traffic safety and guidance devices. More particularly, although not exclusively, it discloses a new and novel roadmarking for improved wet weather visibility and skid resistance. Roadmarkings typically include transverse or longitudinal lines, legends and/or symbols marked in the pavement surface for the regulation and guidance of traffic and for driver information. Prior art roadmarkings are normally applied using paint, thermoplastic or cold applied plastics. In each case there are surface applied glass beads for retro-reflectivity. Such existing markings are generally flat surfaced and therefore have the disadvantage of "drowning" during heavy downfalls of rain. During such events the glass beads become submerged below the level of the surface water accumulating on the roadmarking and are therefore invisible to motorists. While attempts have been made in the prior art to improve wet weather visibility by using larger 1 mm diameter glass beads these are still limited by their level of lift out of the water film above the marker surface. They are generally regarded primarily as "wet recovery systems" which become visible as soon as the rain stops. The skid resistance of prior art markings is also limited by their substantially flat surface which reduces traction and promotes the accumulation of water film. It is therefore an object of this invention to ameliorate the aforementioned disadvantages and accordingly a roadmarking is disclosed which in a position of use on pavement includes a plurality of drainage grooves defined between raised reflective faces whereby during rain retro-reflective means embedded in said faces are disposed above a level of surface water on said roadmarking. 2 Preferably said grooves are shaped, arranged and/or sloped to facilitate drainage of surface water from said roadmarking. It is further preferred that said raised surfaces are generally flat. It is further preferred that said grooves and raised surfaces form a repeating pattern across said roadmarking. It is further preferred that the invention is used for transverse lines, legends and symbols however it may also be adapted for longitudinal delineation. One currently preferred form of the invention will now be described with reference to the attached representations in which: figure 1 shows a typical roadmarking installation in accordance with the invention, figure 2 is a detailed view of the roadmarking surface of figure 1, figure 3 shows a schematic cross-sectional view of the roadmarking surface of figure 2 along the line A-A, and figure 4 shows one preferred form of tool for applying the roadmarking material to a pavement surface. Referring first to figure 1 there is a roadmarking surface 1 shown installed on a paved roadway 2 at the end of a pedestrian island 3 which alerts motorists and provides guidance to traffic. 3 In accordance with the invention and as shown in figures 2 and 3 the surface of the roadmarking is heavily textured with a repeating pattern of elongated raised faces 4 defined between grooves 5. More specifically this textured surface may have a cross-sectional configuration shown in figure 3 where the raised surfaces 4 are substantially flat and are defined between the generally rectangular grooves or troughs 5. Although the invention is not limited to any specific dimensions with the current embodiment the height of the raised surfaces 4 may be about 3 mm above the bases of the grooves 5 and both features may have a width of about 6 mm. The bases of the grooves are preferably about 1 mm above the pavement substrate (see arrows B). Other dimensions for roadmarkings in accordance with the invention may be found appropriate however according to installation and design requirements. The currently preferred material for forming a roadmarking according to this invention is a thermoplastic or cold applied plastic (MMA) which includes: - 40% Potters Pristine Intermix adhesion coated glass bead CHR(AC07) - 10% Titanium dioxide - Surface applied Potters Pristine Intermix adhesion coated glass bead CHR(AC07) with anti-skid aggregate - Thixotrope to prevent material slumping The currently preferred application method uses a screed device with a square notched edge 6. This may comprise a hand trowel as shown in figure 4 or alternatively a hand screed box or screed machine (not shown). The material is prepared in accordance with known techniques and is applied to a clean dry pavement substrate as a viscous homogenous liquid within the standard known 4 temperature and humidity tolerances for thermoplastic and cold applied plastics. The material is preferably applied in long screeds as far as is practical to provide a multiple grooved panel of material. Immediately after, and prior to any gelation/cooling of the base, an even coat of glass bead mix is applied at a rate of approximately 400 g/square metre to achieve 60% bead embedment. Over time a roadmarking with the patterned surface texture of this invention may retain some road grime and dirt build-up. This is preferably removed by a hot pressure wash system with rotary cleaning head and vacuum recovery. One suitable system is the Aussie Hydro-Loop System at approximately 80 degrees C. It will thus be appreciated that this invention at least in the form of the embodiment described provides a novel and useful improvement in roadmarkings. The grooved surface pattern of a roadmarking formed in accordance with this invention provides the following advantages: - Improved drainage of rain water off the roadmarking and enhanced wet night visibility due to grooved surface, - Improved skid resistance due to the pattered macro texture of the roadmarking surface, - Higher luminance due to increased Titanium Oxide content of the roadmarking material, - Improved reflectivity throughout wear life of the material due to high bead content, 5 - Improved bead retention due to use of adhesion coated glass beads, - Improved slip resistance due to the use of surface applied angular aggregate, and - Improved visibility in specular lighting conditions (e.g. a facing sun reflecting off road in front of the observer) due to the textural difference with the surrounding pavement. 6

Claims (4)

1. 2. The roadmarking as claimed in claim 1 wherein said grooves are shaped, orientated and/or sloped to facilitate drainage of said surface water from the roadmarking.
2. 3. The roadmarking as claimed in claim 1 wherein said raised faces are flat and said grooves are generally rectangular in cross-section.
3. 4. The roadmarking as claimed in claim 1 wherein said retro-reflective means are adhesion coated glass beads.
4. 5. The roadmarking as claimed in claim 1 wherein the height of said raised faces is about 3 mm above bases of said grooves and the width of said raised faces and grooves is about 6 mm. Dated this 14th day of October, 2014 David William Eldridge By His Patent Attorney MICHAEL ANDERSON-TAYLOR -7-