AU2019202413B2

AU2019202413B2 - Improved concrete road pavement with more sustainability benefits

Info

Publication number: AU2019202413B2
Application number: AU2019202413A
Authority: AU
Inventors: Duy Huu Nguyen
Original assignee: Individual
Current assignee: Individual
Priority date: 2018-06-17
Filing date: 2019-04-07
Publication date: 2020-10-29
Anticipated expiration: 2039-04-07
Also published as: AU2019202413A1

Abstract

This invention describes an improved concrete road pavement, specially designed for a safer, cheaper and ultimately more sustainable road network. Its unique characteristics, accompanied by practical advantages over traditional pavements, are presented in the following dot points: • Conventionally, a solid section is employed in concrete road pavement. In this invention, concrete road pavement is redesigned to create a hollow channel inside the cross section. The hollow channel can either replace or cooperate with existing drainage system to multiply drainage capacity of the road. This is beneficial to most road networks, especially those suffering the high risk of regular and/or periodical flooding. • As concrete material is more reasonably distributed, the pavement consumes less concrete while ensuring its strength and serviceability under standard traffic. Inside the hollow channel, a permanent formwork structure made of waste plastic is installed, serving as formwork to support concrete placement and water insulation to protect concrete from direct contact with water. The utilisation of waste plastic helps significantly reduce its direct disposal into environment, increasing recycling rate and fostering a sustainable development in modem infrastructure. • The improved pavement utilizes the advanced technology of self-compacting concrete reinforced with steel fibres, resulting in a convenient and easy construction method. This is a dual benefit, as it not only facilitates the construction of the pavement itself, but the integrated hollow drainage channel also evidences a relief of the crucial need of large clearance and/or deep excavation/tunnelling to build new drainage systems. • The pavement is constructed in modules/segments which are assembled on site by flexible joints. The flexible joints increase the flexibility of the pavement compared to conventional design. Combined with more even and smoother top surfaces (benefitted from the technology of self-compacting concrete), the structure promises a noise reduction in service. • The improved concrete road pavement is suitable for both new construction and replacement, with little influence on existing structural facilities. Along with its affordability and constructability, the pavement helps harmonize or overcome most sustainability issues in modem infrastructure, particularly in transport systems. Pa 9 cia CONVENTIONAL CONCRETE PAVEMENT IMPROVED CONCRETE PAVEMENT Example design of an urb n road with 4 traffic lanes Side walk I traffic lane traffic lane 1 traffic lane 1 traffic lane Side walk Hollow concrete pavement (precast in segments/modules) Solid concrete pavement Plastic formwork ( aa ScutPaade Subgrade Lane mark Trench drain Also, lane division DETAIL 1 -W ater drain Additional water storage channel Water drain DETAIL I Longitudinal trench drain Secondary filter Also, lane division Upper plate Base layer Lower plate LVertical wall Flexible connection joint - Internal formiwork (between 2 adjacent Plastic pavement segments)

Description

CONVENTIONAL CONCRETE PAVEMENT IMPROVED CONCRETE PAVEMENT

Example design of an urb n road with 4 traffic lanes Side walk I traffic lane traffic lane 1 traffic lane 1 traffic lane Side walk Hollow concrete pavement (precast in segments/modules) Solid concrete pavement Plastic formwork

( aa ScutPaade Subgrade Lane mark Trench drain Also, lane division DETAIL 1

-W ater drain Additional water storage channel Water drain

DETAIL I Longitudinal trench drain Secondary filter Also, lane division Upper plate

Base layer Lower plate LVertical wall Flexible connection joint - Internal formiwork (between 2 adjacent Plastic pavement segments)

Improved concrete road pavement with more sustainability benefits

1. TECHNICAL FIELD

The present specification relates directly to the field of civil engineering.

2-1. AIMS AND BACKGROUND

This specification describes an improved concrete pavement structure with its numerous benefits toward a safer, cheaper and more sustainable road network. The new structure aims to address four persisting issues that happen in most places globally, listed as follows:

• First, severe and/or periodical flooding, especially in urban road networks, where the arrangement and construction of sufficient drainage facilities are normally difficult;

• Second, rapidly increasing consumption of such construction materials as cement and asphalt, meaning higher environmental impacts from their manufacturing processes;

• Third, low recycling rate of waste materials and the critical necessity to promote more applications, particularly of waste plastic, in modern infrastructure;

• Fourth, intense noise emission due to traffic-pavement interaction, especially on rigid concrete pavements, and its direct link to a variety of health problems.

2-2. SUMMARY OF INVENTION

An aspect of the present disclosure provides a concrete road pavement comprising a plurality of concrete road pavement segments and at least one trench drain extending longitudinally in a direction of traffic, each said concrete road pavement segment adapted to connecting with an adjacent one of the plurality of concrete road pavement segments and comprising: a top plate constituting a road pavement top plate of the concrete road pavement and adapted to serving as a road surface in a traffic lane of a vehicle road; a bottom plate constituting a road pavement bottom plate of the concrete road pavement; a plurality of connecting walls disposed between the top plate and the bottom plate; and a plurality of channels defined by the top plate, the bottom plate and the connecting walls, wherein: the top plate, the bottom plate and the plurality of connecting walls are concrete structures; the top plate has at least one longitudinal jointing edge extending in a direction of traffic for jointing with the adjacent concrete road pavement segment or an adjacent roadside structure via the trench drain; the bottom plate has at least one longitudinal jointing edge corresponding to the longitudinal jointing edge of the top plate for jointing with the adjacent concrete road pavement segment or the adjacent roadside structure; and the plurality of channels are interconnected with each other and adapted to receiving the water through the trench drain, storing the water, and draining the water out into an external drainage system.

Another aspect of the present disclosure provides a concrete road pavement segment for connecting with an adjacent concrete road pavement segment for construction of a concrete road pavement, the concrete road pavement segment comprising: a top plate adapted to serving as a road surface in a traffic lane of a vehicle road; a bottom plate; a plurality of connecting walls disposed between the top plate and the bottom plate; and a plurality of channels defined by the top plate, the bottom plate and the connecting walls, wherein: the top plate, the bottom plate and the plurality of connecting walls are concrete structures; the top plate has at least one longitudinal jointing edge extending in a direction of traffic for jointing with the adjacent concrete road pavement segment or an adjacent roadside structure via a trench drain; the bottom plate has at least one longitudinal jointing edge corresponding to the longitudinal jointing edge of the top plate for jointing with the adjacent concrete road pavement segment or the adjacent roadside structure; and the plurality of channels are interconnected with each other and adapted to receiving water through the trench drain, storing the water, and draining the water out into an external drainage system.

3. DESCRIPTIONS OF THE INVENTION AND ITS BENEFITS

Figures 1 and 2 illustrate the improved concrete pavement structure (right) compared to conventional design (left). It should be noted that all the design values provided in this section are for illustration purposes only and are subject to change, according to specific circumstances. Major characteristics and dominant benefits of the improved design are given as follows:

• First, from conventional design, a solid section is employed in concrete road pavement. In this invention, concrete material is redistributed to create a hollow channel inside the cross section. The purpose is to create an additional water storage channel under and close to the traffic surface. The channel may work either independently or cooperatively with existing drainage system (e.g. longitudinal water drain pipes). Once successfully constructed, the channel multiples drainage capactyof the road. For example, for an urban road with 4 traffic lanes in figures 1 and 2, assuming that the width of each lane is 3.5m and inner diameter of each longitudinal water drain pipe is 0.8m (i.e. cross sectional area of 0.5m 2 each), the hollow channel with its average depth ranging from 15cm to 20cm can provide an additional cross-sectional storage area of 1.0-1.4m 2 each side, which is at least 2 times larger than the capacity of the main water drain pipe alone.

Importantly, the water channel utilizes free- as well as large area right under road surface; as a result it eases up the critical need for a large area clearance to build new drainage systems. Moreover, the channel is close to the surface, making it easier to construct compared to deep excavation/tunnelling.

• Second, cross section of the improved pavement is redesigned with more reasonable material distribution, resulting in less concrete consumption while ensuring its sufficient strength under heavymovng trafc For the example design in figures 1 to 3, with chosen thicknesses of the top and bottom plates of 8cm and connection walls of 20cm, depending on the average depth of the water channel, the new pavement consumes 20 30% less concrete compared to conventional design. Less material consumption in the improved pavement also means lighter pavement self-weight, which is another plus point for foundation treatment.

From structural analysis, beside its self-weight and water, the improved pavement in the example above performs well under a moving traffic load of 30 tonnes. For all critical situations considered in the analysis, maximum tensile stresses in the pavement are lower than 50% tensile strength of concrete (assuming that a concrete type with a compressive strength of 40MPa at 28 days of age is in use).

• Third, self-compacting concrete (SCC) with steel fibres addition are preferably primary materials of the improved pavement, although other types of concrete and fibres may also be used. Employment of SCC and steel fibres results in a high-quality structural member, accompanied by a convenient construction method (.e. less labour and machinedemand).

Importantly, a permanent internal formwork made of either new, waste plastic or other suitable materials is introduced as a direct water storage. The formwork is designed to be sufficiently strong and impervious, which not only supports concrete placement but also covers all surfaces of the internal water channel. From that, it prevents water seepage through concrete that may downgrade the pavement itself and other structural layers (e.g. base, subgrade, foundation etc.). In this invention, waste plastic is strongly promoted. Once applied, the amount of waste plastic consumed for the improved pavement significantlycontributes to sustainabilitcoals in the area. As an illustration, with a 4-lane road shown in figures 1 and 2, assuming a uniform formwork thickness of 8mm, an average depth of the internal water channel of 20cm and a plastic density of 1g/cm 3, the amount of waste plastic required for 100m length of the road is approximately 22 tonnes.

• Fourth, the improved pavement is preferably constructed in modules/segments. Such segments are then connected on site with flexible joints to form a semi-rigid structure (i.e. with higher flexibility compared to conventional design). Combined with more even and smoother top surface (i.e. because of finer aggregates employed for SCC), the structure promises noise reduction in service.

• Finally, the improved pavement may be flexibly cast in situ or precast and is appropriate for both small and large-scale applications. Its new construction or replacement can be carried out with littleinfluence on existing structural faci/tes,as shown in figures 1 and 2.

These five characteristics, along with its affordability and constructability, help the new structure significantly reduce severe impacts caused by all the persisting issues mentioned in Section 2.

4. ADDITIONAL CHARACTERISTICS PROVIDED IN FIGURES 1 TO 3

FIGURE 1:

Figure 1 describes a typical arrangement of the improved pavement and its relationship to other structural facilities on road. In this example (i.e. from both figure 1 and other figures), internal formwork is specified as plastic, however other suitable materials may also be used.

• Structural road layers beneath the pavement may remain similar to those in conventional design. Affected structures include concrete kerbs and median strip, where slight adjustments in their designs (as shown in the figure) may be necessary to facilitate the integrations with the pavement segments.

• Bottom plate of the cross section is preferably constructed with a transverse downward grade to facilitate water drainage. In case a downward grade is applied, the improved pavement, as a result, has increasing depth from inner lane(s) outward.

• Top plate of the cross section may be either flat (i.e. with no transverse grade) or with a downward grade. The downward grade of the top plate should not be greater than that of the bottom plate.

• Internal water channel in the improved pavement is preferably connected to existing water drain pipes, or it may work independently. If the channel is designed as an independent drainage system, longitudinal grade of the road may be included to facilitate water flow.

FIGURE 2:

Figure 2 shows a 3D perspective view of the improved pavement, with more details over the longitudinal and transverse flexible joints.

• Longitudinal joints, also acting as trench drains, are preferably made of high-strength steel covers and plastic seals; however, other suitable types of connection joint and material may also be applied.

• Longitudinal trench drains are preferably arranged at lane separation locations. In that case, top covers are designed to have sufficient width to facilitate the installations of lane marks and other facilities, as required in current standards.

• To prevent coarse materials from entering and being trapped inside the water channel, a secondary filter layer may be employed along each longitudinal trench drains. Steel grate with fine round holes is preferable in this design; however, other suitable materials and grate designs may also be used.

• Transverse joints are employed to connect two neighbouring pavement segments along the road, to provide a continuous top surface and ensure comfortable traffic. Transverse joints are constructed on site, which may contain reinforcement grids with internal anchors and filling concrete. However, other suitable connection methods and materials may also be used.

• Thickness of transverse joints is less than the average depth of the pavement segments. The purpose is to create higher longitudinal flexibility of the whole pavement system. The presence of such flexible joints helps reduce possible damage in pavement segments due to non-uniform settlement of foundation. In addition, it allows convenient repair/maintenance in service.

FIGURE 3:

Figure 3 provides the basic design of one pavement segment with its three typical cross sections.

• The pavement segment consists of a top plate, connection walls and a bottom plate. All those major components are preferably cast simultaneously, based on the internal formwork and other external facilities, to form a monolithic segment. The top and bottom plates may have either similar or different thicknesses.

• The connection walls include longitudinal and transverse walls. Number, location and dimension of these walls may vary depending on specific design circumstances. However, one transverse wall is preferably located at each end of the pavement segment, along the road, to carry the impact of moving traffic and reduce possible damage due to the edge-curling effects. Longitudinal walls may have either similar or different thicknesses.

• Preferably, the length and width of each pavement segment are equal to the total width of one or more traffic lane(s). With this arrangement, longitudinal connection joints (and trench drains) are located at lane division areas rather than within a traffic lane. From that, it ensures comfortable traffic. The width of each pavement segment may be either equal to its length or different.

• The internal water storage channel includes a number of chambers, separated by longitudinal walls. Along the road, these chambers are separated at the positions of transverse walls. The chambers are preferably connected to each other, and to the neighbouring longitudinal trench drains, at positions adjacent to the transverse walls. For each segment of the water storage channel, at least two connection points should be provided. From that, they may receive, store and transfer water to lower locations with minimum obstruction.

• The pavement areas, at the locations of chambers' connection points, due to less concrete distribution, may be further reinforced by steel grids, both at top and bottom plates.

• Reinforcement grid at the top plate may be extended to the closest transverse flexible joints. Internal anchors may be installed on the extended portion of the top reinforcement grid to facilitate the construction of transverse flexible joints on site.

5. LIST OF EXTERNAL REFERENCES ADOPTED IN THIS SPECIFICATION

Figure 2 adopts several external references for demonstration purposes. Although these references have no contribution to the nature of this invention, they are also acknowledged and are listed as follows:

• Trees: XfrogPlants Blue-Gum Eucalyptus by xfrog, licensed under Royalty Free License All Extended Uses

https://www.turbosquid.com/3d-models/blue-gum-eucalyptus-tree-blue-3d model/548015

• Buildings: Lowpoly Build11 by ERLHN, licensed under Royalty Free License - All Extended Uses

https://www.turbosquid.com/FullPreview/Index.cfm/ID/689820

Claims

The claims defining the invention are as follows:

1. A concrete road pavement comprising a plurality of concrete road pavement segments and at least one trench drain extending longitudinally in a direction of traffic, each said concrete road pavement segment adapted to connecting with at least an adjacent one of the plurality of concrete road pavement segments and comprising: a top plate constituting a part of a road pavement top plate of the concrete road pavement and adapted to serving as a road surface in a traffic lane of a vehicle road; a bottom plate constituting a part of a road pavement bottom plate of the concrete road pavement; a plurality of connecting walls disposed between the top plate and the bottom plate; and a plurality of channels defined by the top plate, the bottom plate and the connecting walls, wherein: the top plate, the bottom plate and the plurality of connecting walls are concrete structures; the top plate has at least one longitudinal jointing edge for jointing with the adjacent concrete road pavement segment or an adjacent roadside structure via the trench drain; the bottom plate has at least one longitudinal jointing edge corresponding to the longitudinal jointing edge of the top plate for jointing with the adjacent concrete road pavement segment or the adjacent roadside structure; and the plurality of channels are interconnected with each other and adapted to receiving the water through the trench drain, storing the water, and draining the water out into an external drainage system.

2. The concrete road pavement according to claim 1, wherein the road pavement bottom plate has a transverse downward grade towards an edge of the vehicle road.

3. The concrete road pavement according to claim 2, wherein the road pavement top plate has a transverse downward grade towards an edge of the vehicle road, and the transverse downward grade of the road pavement top plate is not greater than the transverse downward grade of the road pavement bottom plate.

4. The concrete road pavement according to any one of claims 1 to 3, wherein each of the plurality of channels are formed with a plastic internal formwork.

5. The concrete road pavement according to any one of claims 1 to 4, wherein the plurality of connecting walls comprises a plurality of longitudinal walls extending longitudinally along a direction of traffic, and a plurality of transverse walls extending transversely across a direction of traffic, thereby defining a plurality of longitudinal channels and a plurality of transverse channels interconnected with each other.

6. The concrete road pavement according to any one of claims 1 to 5, wherein the top plate, the bottom plate and the connecting walls of each of the plurality of concrete road pavement segments are made of self-compacting concrete reinforced with steel fibres.

7. The concrete road pavement according to any one of claims 1 to 6, wherein the top plate, the bottom plate and the connecting walls of each of the plurality of concrete road pavement segments are integrally formed.

8. A concrete road pavement segment for connecting with an adjacent concrete road pavement segment for construction of a concrete road pavement, the concrete road pavement segment comprising: a top plate adapted to serving as a road surface in a traffic lane of a vehicle road; a bottom plate; a plurality of connecting walls disposed between the top plate and the bottom plate; and a plurality of channels defined by the top plate, the bottom plate and the connecting walls, wherein: the top plate, the bottom plate and the plurality of connecting walls are concrete structures; the top plate has at least one longitudinal jointing edge extending in a direction of traffic for jointing with the adjacent concrete road pavement segment or an adjacent roadside structure via a trench drain; the bottom plate has at least one longitudinal jointing edge corresponding to the longitudinal jointing edge of the top plate for jointing with the adjacent concrete road pavement segment or an adjacent roadside structure; and the plurality of channels are interconnected with each other and adapted to receiving water through the trench drain, storing the water, and draining the water out into an external drainage system.

9. The concrete road pavement segment according to claim 8, wherein a width of the concrete road pavement segment is equal to a total width of one or more of the traffic lanes and the concrete road pavement segment is adapted to jointing with the adjacent concrete road pavement segment at a dividing line between two adjacent traffic lanes.

10. The concrete road pavement segment according to claim 8 or 9, wherein the bottom plate has a transverse downward grade.

11. The concrete road pavement segment according to claim 10, wherein the top plate has a transverse downward grade in a same direction as the transverse downward grade of the bottom plate, and the transverse downward grade of the top plate is not greater than the transverse downward grade of the bottom plate.

12. The concrete road pavement segment according to claims 8 to 11, wherein each of the plurality of channels are formed with a plastic internal formwork.

13. The concrete road pavement segment according to any one of claims 8 to 12, wherein the plurality of connecting walls comprise a plurality of longitudinal walls extending longitudinally along a direction of traffic, and a plurality of transverse walls extending transversely across a direction of traffic, thereby defining a plurality of longitudinal channels and a plurality of transverse channels interconnected with each other.

14. The concrete road pavement segment according to any one of claims 8 to 13, wherein the top plate, the bottom plate and the connecting walls are made of self-compacting concrete reinforced with steel fibres.

15. The concrete road pavement segment according to any one of claims 8 to 14, wherein the top plate, the bottom plate and the connecting walls are integrally formed.

16. The concrete road pavement according to any one of claims 1 to 7, wherein the trench drain comprises: a high-strength steel cover fixed on top of the two adjacent ones of the concrete road pavement segments; a plastic or silicone layer placed at a bottom gap for water sealing; and a secondary filter layer installed underneath the steel cover.

17. The concrete road pavement according to any one of claims 1 to 7, wherein the top plates of two of the concrete road pavement segments are connected via a transverse joint constructed with filling concrete reinforced by steel grids and embedded anchors.

18. The concrete road pavement according to any one of claims 16 and 17, further comprising reinforcing steel grids across the top plates of two adjacent ones of the concrete road pavement segments and reinforcing steel grids across the bottom plates of the two adjacent ones of the concrete road pavement segments.

19. The concrete road pavement according to claim 18 when appended to claim 17, wherein the reinforcing steel grids in the top plates are extended to a closest one of the transverse joints and the embedded anchors are installed on extended portions of the reinforcing steel grids.

Duy Huu Nguyen By Patent Attorneys for the Applicant