DESC:FORM 2
THE PATENT ACT 1970
(39 OF 1970)
AND
The patent rules, 2003
COMPLETE SPECIFICATION
(See section 10: rule 13)

1. TITLE OF INVENTION
Pre-tensioned Precast Concrete Pavement

2 APPLICANTS
Sr. No Name Nationality Address
1 Dr. R. S. Sonparote Indian Applied Mechanics Department, VNIT, South Ambazari Road, Nagpur, Maharashtra, India.440010
2 Ameen Syed Indian Applied Mechanics Department, VNIT, South Ambazari Road, Nagpur, Maharashtra, India.440010

3. PREAMBLE TO THE DESCRIPTION

COMPLETE
Following specification particularly describes the invention

4. DESCRIPTION.

DECLARATION:
Following specification claims priority from previously filed provisional specification at Indian patent office on 23/12/2015 having patent application number 4843/MUM/2015.

Technical field of invention:

Present invention in general relates to roadway construction and repair and more particularly to construction and installation of precast pre-tensioned pavement panels of optimum quality for increasing the speed of construction.

Prior art:

Pre-stressed concrete is a mode of construction that overcomes concrete's inherent weakness in tension. When concrete is pre-stressed, longer spans can be created as compared to ordinary reinforced concrete. Traditional reinforced concrete uses steel rebar or other reinforcement material disposed within the concrete to reinforce it. Typically long span bridge girders are made in this manner. Pre-stressed concrete employs cables or strands to provide a clamping load which produces a compressive stress that can balance the tensile stress that the concrete member would be subjected to due to a bending load.

Pre-stressed concrete can be either pre-tensioned, or post tensioned. Concrete is cast around already tensioned tendons. The concrete is poured around the pre-tensioned cables or tendons, and the concrete adheres to the tendons or cables as the concrete hardens during the curing process. When the tension is released from the tendons/cables, the tendons tends to return to their original state thereby applying compression on concrete via tendon concrete bond. To achieve the pre-tensioning, anchor points are attached on opposite ends of the casting bed, between which, the tendons or wires are stretched in a straight line.

US 8636441 B2 discloses dual direction pre-stressed pre-tensioned precast concrete slabs and process for same. A precast roadway slab is pre-tensioned longitudinally and transversely, and may also be post-tensioned. A casting bed has the capability of permitting pre-tensioning of a concrete cast to be carried out within the casting bed in both the longitudinal direction and in the transverse direction. Slots are provided at regular intervals within the side walls and jacking heads of the casting bed for tensioning wires to pass there through for pre-tensioning. The process utilizes a multilayer grid of pre-tensioning wires disposed within the casting bed, prior to pouring of the concrete. The cast concrete product can also be made with optional tubular ducts, laid parallel to the longitudinal wires, for post-tensioning subsequent to the cast of the concrete. The post-tensioning of the hardened cast, if called for, takes place at the job site.

CN 102535295 B discloses fabricated pre-stressed heat-resistant cement concrete pavement and construction process thereof. The invention discloses a process for the assembly and construction of heat-resistant pre-stressed concrete pavement, their road lay side by side and are connected by transverse pre-stressing strand as one of the multi-channel assembly pre-stressed road panel assembly composed of heat-resistant; pre-stressed assembly thermal resistance path panel comprises a plurality of road sections are connected by webs pre-stressed assembly consisting of pavement and spread fabricated pre-stressed concrete pavement vermiculite board thermal resistance overlay, including road blocks by longitudinal pre-stressing strand is connected as one of the plurality of ordinary plate, connecting plate and common plate are precast concrete blocks; its construction process is as follows: First, precast concrete precast blocks; second, precast concrete blocks transport; third, pavement. Pavement structure of the present invention designed, easy construction, with heat resistant properties and low input costs, the construction period is short, easy to guarantee the quality of construction, can solve a variety of practical problems of the conventional prefabricated cement concrete pavement exists.

CN 203716492 U describes pre-tensioned pre-stressed concrete beam plate bottom formwork. The pre-tensioned pre-stressed concrete beam plate bottom formwork comprises a hardened foundation located on the bottommost layer, the hardened foundation is paved with a broken stone hardcore, the broken stone hardcore is covered with concrete paved with reinforcing mesh sheets, two pieces of angle iron are embedded in the concrete, and the position between the two pieces of angle iron is paved with water stones with the surface coated with paraffin. According to the pre-tensioned pre-stressed concrete beam plate bottom formwork, construction is easy, the quality of components is easy to control, a bottom die can be repeatedly used, the construction progress is accelerated, construction cost is reduced, and construction benefits are increased.

Another US 20130264394 A1 discloses pre-stressed concrete track slab of slab-type ballast-less track provided in the disclosure is a pre-stressed concrete track slab of slab-type ballast-less track, which includes a slab body, on which fastening embedded casings are arranged. At least one row of longitudinal common steel bars and at least one row of transverse common steel bars are arranged in the slab body along a length direction and a width direction. The longitudinal common steel bars are insulated from the transverse common steel bars. At least one row of longitudinal pre-stressed steel bars and at least one row of transverse pre-stressed steel bars are fastened in the slab body along the length direction and the width direction through anchor backing plates and fastener devices. In the pre-stress directions of the longitudinal pre-stressed steel bars and the transverse pre-stressed steel bars, it is post-tensioned in both directions or it is pre-tensioned in one direction and post-tensioned in the other direction. Limiting structures and grounding terminals are also arranged on the slab body. The pre-stressed concrete track slab has the characteristics of light structural dead weight, small structure height, low manufacturing cost and deformation resistance.

CN 202718022 U discloses a fabricated type pre-stressed concrete pavement. The fabricated type pre-stressed concrete pavement comprises a pre-stressed tendon mesh paved on a roadbed, and at least two prefabricated concrete pavement slabs are paved on the pre-stressed tendon mesh. The pavement structure is used for emergency repair of after-calamity roads, or used for constructing and maintaining roads conventionally, and has multiple advantages of being convenient to install, fast in construction speed, low in construction cost, low-carbon and environment-friendly and the like, and improves the rescue timeliness.

Prefabricated cement pavement slab for quick pavement repair is disclosed in CN 103498397 A. The prefabricated cement pavement board comprises a cement concrete pavement slab, force transmission rods and internal steel bars, wherein the force transmission rods are arranged in the center of the total thickness of the two side plates of the slab at intervals; the internal steel bars are arranged in the slab and are used for preventing the slab from being warped. The pavement slab provided by the invention is fabricated in a factory building in advance and is transported to a pavement to be repaired for pavement replacement; the pavement replacement operation is performed at 10 p.m. and the pavement is opened to traffic at 5 a.m. on the next day, so that the prefabricated cement pavement slab is efficient and durable.

US 6435765 B1 discloses athletic track with post-tensioned concrete slab. An athletic track having a post-tensioned concrete slab supporting a resilient surface is mentioned. The athletic track has opposed parallel rectangular side areas and opposed semi-circular end areas connecting the side areas. The concrete slab is cast in place without requiring expansion joints between segments. Cables are cast into the slab for providing a tension load in the concrete slab. A first set of cables is tilted away from the perpendicular in a first direction while a second set of cables is parallel to the edges of the rectangular areas such that members of the second set of cables cross members of the first set of cables. A third set of circumferential cables is provided in the semi-circular end areas. A fourth set of cables intersecting the circumferential cables is non-radially disposed. The slab has a relatively flat lower surface. Pour strips situated along a line of symmetry are provided between adjacent quadrants of the end areas.

CN 203514143 U discloses a precast cement road panel for rapid maintenance of a pavement. The precast cement road panel comprises three parts, namely a cement concrete road panel, dowel bars and an internal reinforcing steel bar, wherein the dowel bars are arranged at thick centers of two sides of the panel at an interval of a fixed distance; the reinforcing steel bar is arranged inside the panel to prevent the panel from warping. The road panel disclosed by the utility model is fabricated in advance inside a factory, and can be transported to the to-be-maintained pavement to change the pavement, and the pavement can be opened to traffic after being repaired from ten at night to five in the morning on an alternate day. Thus, the precast cement road panel is efficient and durable.

Consequently to overcome the shortcomings presented by regular concrete pavement there is need to introduce and develop an improved and efficient system and method for the construction of concrete pavement. Hence the present invention provides a new technique and method for pre-tensioned precast concrete pavement. A pre-tensioned precast concrete panel is implementing and these panels are cast in a controlled environment and hence are of the optimum quality.

Object:

1. Primary object of the present invention is to provide method for the implementation of Pre-tensioned Precast Concrete Pavement.

2. Another object of the present invention is to implement pre-tensioned precast concrete panels.

3. Yet another object of the present invention is to cast the panels in a controlled environment and provide optimum quality.

4. Yet another object of the present invention is to increase the tensile strength of the concrete panel thereby increasing its life.

5. Yet another object of the present invention is to provide a new and improved load transfer mechanism that will reduce the construction cost.

6. Yet another object of the present invention is to reduce the construction time required on site.

7. Yet another object of the present invention is to help in reducing the traffic congestions and thereby decreases the probability of accidents.

8. Yet another object of the present invention is to provide easy repairing of the existing pavement.

9. Yet another object of the present invention is to provide a method which helps to reduce the time of construction and also proves to be economical.

10. Yet another object of the present invention is to provide longer life and reduces the pavement thickness.

Other objects, features and advantages will become apparent from detail description and appended claims to those skilled in art.

STATEMENT:
Accordingly following invention provides a method and technique for construction of Pre-tensioned Precast Concrete Pavement. The proposed technology provides a new method for construction, installation and application of precast concrete pavement and pre-tensioned precast concrete panels. Since the panels are already prepared in a yard, the construction time required on site reduces considerably. This in turn, helps in reducing the traffic congestions and thereby decreases the probability of accidents. Pre-stressing increases the tensile strength of the concrete panel thereby increasing its life. The invention in general provides a method of construction of a pre-fabricated pavement panel which is pre-tensioned along its width. The panels are to be constructed in a casting yard up to the optimum quality and then transported to the site. The load transfer between these panels is facilitated by a single dowel running along the width of the pavement. The dowel is positioned such that it passes through the projections present in two adjacent panels thereby facilitating the load transfer. Another part of the invention is the panels at the expansion joints. These panels are provided with slots along the traffic direction. Once the dowels are inserted into the slots of both the panels adjacent to the expansion joint, the gap in the slots can be filled with a grout. The preferred embodiment mainly comprises of pre-stressing tendons, panel, grouting material, dowel bars, etc.

BRIEF DESCRIPTION OF DRAWING:
This invention is described by way of example with reference to the following drawing where,

Figure 1 of sheet 1 shows Isometric View of Pre-tensioned Precast Concrete Panel.
Where,
9 & 14 denotes slot
10 denotes Slab panel
11 denotes Width of projection
12 denotes Duct
13 denotes

Figure 2 of sheet 1 shows Plan of Pre-tensioned Precast Concrete Panel.
Where,
3 denotes ducts for load transfer
4 denotes ducts for load transfer and grout port
5 denotes prestressing ducts
6 denotes length of an individual panel
7 denotes Width of an individual panel

Figure 3 of sheet 2 shows Section 3 of plan, sectional view of dowel provided for inter panel load transfer.
Where,
15 denotes Passing rod
16 denotes grout.

Figure 4 of sheet 2 shows Section 4 of plan, grout port provided for grouting of dowel slots.
Where,
17 denotes regular concrete (min M40)
18 denotes grout via grout port

Figure 5 of sheet 3 shows Section along the Pre-tensioning tendon.
Where,
19 denotes Tendon.

Figure 6 of sheet 3 shows Mold required for the casting of the mid panels (panel 10).
Where,
20 denotes Mold
21 denotes d
22 denotes d

Figure 7 of sheet 4 shows Isometric view of end panel required at expansion joints.
Where,
23 denotes face
24 denotes Slot
25 denotes Slab
26 denotes Slot
27 denotes face

Figure 8 of sheet 4 shows Mold required for the casting of the end panels (panel 25).
Where,
28 denotes Duct
29 denotes Duct
30 denotes mold.

In order that the manner in which the above-cited and other advantages and objects of the invention are obtained, a more particular description of the invention briefly described above will be referred, which are illustrated in the appended drawing. Understanding that these drawing depict only typical embodiment of the invention and therefore not to be considered limiting on its scope, the invention will be described with additional specificity and details through the use of the accompanying drawing.

Detailed description:

The application of pre-tensioned precast concrete pavement (PPCP) gives us numerous advantages. Pre-stressing increases the tensile strength of the concrete panel thereby increasing its life. Hence the same depth of regular pavement will have a shorter life as compared to PPCP. If the pavement has to be designed for the same design life as that of regular concrete pavement, then the application of pre-stressing will give us an advantage by reducing the thickness of the pavement. This reduced thickness decreases the temperature difference along the depth, thereby reducing temperature stresses.

Since the panels are to be casted in a yard, the quality can be maintained as required. The inability to use higher grade of concrete for pavement is removed. The controlled environment in a casting yard allows us to use higher grade concrete without worrying about the shrinkage cracks. The factory product is finally to be transported to the site, and can be tested well before applying it on site, thereby dismissing any need of immediate repair that is generally required in a regular concrete pavement.

Since the panels are pre-tensioned the probability of development of early age cracks is negligible as compared to a regular pavement. The edges of the roads are the weakest section in a regular pavement, but are strengthened in PPCP due to high pre-stressing force at these edges.

A general concrete pavement of 7.0 m width and 1 km length, requires a minimum of 94 days for construction as per regular practice. During this period no traffic flow is allowed over the newly constructed pavement. By the application of PPCP, the same area can be covered within 32days (approx.). This reduction in time saves the cost associated with it. Opening of traffic can be done immediately after laying the panels. The cost benefits are further enhanced when applied on a BOT project.
If a concrete pavement is to be constructed in an urban area having high traffic intensity, it increases the chances of accidents. The longer it takes to complete the project the cost also increases exponentially. All of these difficulties can be removed if the construction activity could be carried out during the night hours and the traffic could be allowed during the day hours. This is only possible by the application of precast pavement technology. By using PPCP we can ensure the repair of a pavement in a high traffic area to be done faster.

Since the cost related to saw cutting, curing, excess concreting, traffic controlling, etc. are reduced by the application of PPCP, an overall cost benefit is obtained. Even though an excess cost of pre-stressing is required in PPCP panels, for most of the site conditions this technology shall prove to be economical.

Panel details:
The proposed pavement panels are pre-stressed along the width. This pre-stressing force helps reduce the tensile stresses and in turn reduces the required thickness of the pavement. The size of a panel may be restricted to 3.5m x 4.5m. This restriction helps control the temperature stresses. If a road of higher width is to be constructed, then panels can be placed laterally adjacent to each other. A nominal gap is to be maintained laterally between the panels so as to insert the filler material that will avoid any percolation of water to the base of the slab. On the longitudinal face of the panels an interlocking arrangement has been provided as shown in figure 1. This arrangement facilitates the load transfer between the panels longitudinally. The number of projections in panels depends upon the major traffic direction, the grade of concrete and the type of soil on the site. The width of each projection might vary depending upon the type of traffic expected in the area where the pavement is being laid. The pre-tensioning is to be performed laterally i.e. perpendicular to the traffic direction, thereby developing higher compression zones at the lateral edges of the panels. The diameter of the strands and the pre-stressing force applied to them will vary depending upon the expected load that will be applied on the pavement in its design life. At the expansion joints, dowel bars are to be provided as per the design requirement. The dowel bars are to be inserted in the slot available in the end panels. This slot is to be grouted later with a suitable grouting material. The details of the end panels are given in figure 2. The expansion joints are to fill using bituminous sand mix as is done in a regular pavement. In a regular pavement we require saw cutting after every few meters. These saw cuts then are required to be filled up with a sealant material. In PPCP saw cutting is not required as there is no transfer of temperature stresses in between the panels.

Lifting and Placing of Panels:
Once PPCP panels are completed and have gained the required strength, they are to be transported to the required site. The process of lifting, transporting and placing the panels on site is a very critical stage, since the chances of damage to the finished panels is the highest during this period. A four point lifting mechanism has been proposed for this purpose. The panels are to be lifted from the curing tank in the casting yard and stacked on a suitably levelled platform. A maximum of 4 panels can be stacked one over the other. The weight of panels may vary within the range of 6 MT to 11 MT. A crane suitable for carrying that much load is needed to lift the panels from the stack and place them on a flatbed truck for transportation. A suitable lifting hook are to be embedded in the concrete panels, such that they can be plugged or grouted later on before the opening of traffic. Special confining reinforcement is to be provided at the locations where the lifting hooks are to be embedded. Stresses are developed while lifting the panel due to its self-weight and swinging action that might occur during moving the panel while it’s in a suspended state.

Base Preparation:
The base preparation for laying a new PPCP is same as regular pavement. It is absolutely necessary that a perfect base is present on which the panels are placed. To ensure this perfect base, a layer of lean concrete/DLC is to be applied as the top layer of the prepared base. The load transfer should occur from the panel to the soil via the base. This load transfer should be uniform throughout the area of the panel, as any unevenness may cause development of high amount of excessive stresses. In cases where it’s not possible to provide a perfectly level base, a thin layer of a suitable material (depending upon the situation) is to be used so as to ensure uniform contact between the panel and the base.

PPCP panels can also be used for repair of existing pavements. In cases where the panels are to be laid over existing pavement, a thick layer of suitable material needs to be spread in order to fill up the damages in the existing road and prepare a uniform base. The construction activity in such areas can be conducted at the night hours and the traffic can flow freely during day time. The panels that are required for repair of existing damaged pavement are provided with slight curl given in the base of the slab. This curve is provided so that the panel can rest uniformly and firmly on the base laid on the damaged pavement and the material used for leveling does not excessively flow out from beneath the panels.
In order to provide better understanding of the present invention, the present invention is described below taking an example of one of the preferred embodiments with the help of drawings. It should be understood that various changes, modifications and amendments may be made without deviating from the primary scope of the claim. The scope of the invention will not be limited to the specified materials, sizes, shapes, etc. The drawings are not necessarily drawn to scale but are intended to effectively describe the invention.

Figure 1 represents the slab panel 10 that is constructed by pouring a suitable material, like high strength concrete, fiber reinforced concrete, etc. into mold 20 (Refer Figure 6). Slab 10 may have the dimension as 3.5 m x 4.5 m, but is not restricted to this size. The width of the panels may be varied as per the width of the road. Slab 10 is pre-tensioned along the width by a plurality of tendon 19. Tendon 19 may be made of a suitable material such as high tensile steel, low relaxation high strength steel, etc. The diameter, prestressing force and spacing of tendons may vary as per requirement. The thickness of the slab 10 may vary from 200 mm to 350 mm. The thickness of panel, prestressing force and diameter and spacing of tendons are based upon the base strata strength, traffic conditions, design life and temperature variations. The length of the panel may differ as per lifting and handling convenience, and as per its effect on the development of temperature stresses.
The top surface of the panels is to be tinned finished while the side faces and the bottom surface are to be kept smooth. The side surface should be such that they are perfectly matching so that the panels are not eccentric to each other. A nominal gap that might be present between the panels may be filled by a suitable filler material. This filler material shall be such that it will avoid any percolation of water to the base of the slab and will facilitate nominal expansion of the panels.
On face 9 and 14, multiple projections such as 11, are present. They facilitate the load transfer between panels. The number of projections in a panel depends upon the major traffic direction and the grade of concrete. The width of each projection might vary between 200 mm to 700 mm. The projections are provided with ducts such as 12. These ducts are required for passing rod 15. The size of the duct may vary from 16mm to 32mm. The rod may be of a material similar to high strength steel. The size of duct and rod, width of projection 11 and its number, depends on the type of traffic expected in the area and the soil strata condition at site. The excess gap that remains after inserting rod 15 may be filled by a suitable grout 16. The grouting agent should be such that it has good bonding with concrete as well as rod 15 and is capable of filing any voids present between rod and concrete.
A slab 25 is constructed resembling slab 10 in all aspects except face 23 (Refer Figure 7). On face 23 there are plurality of slot 24 present. These slots facilitate the transfer of load across the expansion joint by the insertion of dowel bars. Slot 26 is present for grouting, similar to slot 14 present in slab 10. The procedure of grouting is same as that in slab 10 but may vary as per the requirement. The dowel bars that are to be inserted in slot 24 have similar material property as that of rod 15. The length of the dowels determines the length of slot 24.

All the dimensions specified in the document are stated here only as an example and subjected to variation as per the requirement.
Figure 8 depicts the form work required for the casting of slab 25. The slots that are required at face 23 of slab 25 are maintained to the required size by providing duct 28 in the mold. Duct 29 is provided so that slot 26 stays free from concrete and available for grouting on a later stage.

Best method of performance of the invention:
1. Pre-tensioning bed is to be prepared according to the number and size of panels to be casted.
2. Number of mold needs to be prepared as per the site requirement by referring Figure 6 and Figure 8.
3. The pre-tensioning of tendons is to be performed using a suitable pre-tensioning mechanism, available commercially.
4. Concreting of the required grade is to be done (min. M40) in the mold 30 and 20. Care needs to be taken to keep the ducts 21, 22, 28 and 29 free from excessive concrete and to keep it in place while concreting.
5. Surface has to be prepared with a tinned finish so as to get a good riding quality.
6. Tendons 19 are cut, as soon as the concrete has gained sufficient strength.
7. When further strength has been gained by concrete, the panels are lifted and inserted into the curing pond.
8. After concrete has gained the required strength, the panels are to be lifted from the curing tank and stacked on a suitably leveled surface.
9. Care should be taken to stack a maximum of 4 panels one over the other.
10. The panels are to be lifted via a four point lifting mechanism, by a crane and mounted on a flatbed truck for transporting them on site.
11. Care should be taken while lifting and placing the panels so as to avoid any swinging action.
12. The panels are then lifted using a crane on site and are to be placed accurately at the required position.
13. The panels may be provided with a suitable lifting hook that may be embedded while concreting.
14. Once the panel has been placed in its final position, the openings left by the hooks maybe filled by a suitable grout.
15. The base preparation is to be performed on site as per the regular procedure.
16. The topmost layer of the base prepared should necessarily be that of lean concrete or DLC or that specified as per the site conditions.
17. The top surface of the base needs to be perfectly leveled as per the required pavement profile.
18. If the top surface is not perfectly leveled, a thin layer of suitable material such as lean concrete, treated flyash, etc. is to be applied as a leveling course.
19. Panels are to be placed preferably when the leveling course is in a plastic state.
20. At the expansion joints the dowels are to be inserted in one of the panels adjacent to the joint.
21. In cases where the panels are to be laid over existing pavement, a thick layer of suitable material needs to be spread in order to fill up the damages in the existing road and prepare a uniform base.

Additional advantages and modification will readily occur to those skilled in art and shall be further elaborated in following complete specification. Therefore, the invention in its broader aspect is not limited to specific details and representative embodiments shown and described herein. Accordingly various modifications may be made without departing from the spirit or scope of the general invention concept as defined in the specification.
,CLAIMS:CLAIMS

1. A pre-tensioned precast concrete panel (PPCP) that is pre-tensioned along the width and is provided with an inter panel load transfer mechanism, that may be used as a pavement panel wherein the inter panel load transfer system comprises of a plurality of projections consisting of a slot formed along the width of the projection wherein a single full width dowel may be inserted to facilitate load transfer.

2. The pavement panels as claimed in claim 1 are pre-stressed along the width which helps reduce the tensile stresses and in turn reduces the required thickness of the pavement.

3. The PCP panels as claimed in claim 1 when required for repair of existing damaged pavement may be provided with a slight curl given in the base of the slab so that the panel can rest uniformly and firmly on the damaged pavement base and the material used for leveling does not excessively flow out from beneath the panels.

4. The Pre-tensioned Precast Concrete Panel as claimed in claim 1 and as shown in Figure 1 represents the slab panel 10 that is constructed by pouring a suitable material, like high strength concrete, fiber reinforced concrete, etc. into mold 20 (Refer Figure 6) wherein
a) Slab 10 may have the dimension as 3.5 m x 4.5 m, but is not restricted to this size;
b) The width of the panels may be varied as per the width of the road;
c) Slab 10 is pre-tensioned along the width by a plurality of tendon 19;
d) Tendon 19 may be made of a suitable material such as high tensile steel, low relaxation high strength steel, etc;
e) The diameter, prestressing force and spacing of tendons may vary as per requirement;
f) The thickness of the slab 10 may vary from 200 mm to 350 mm;
g) The governing factors for determining the thickness, prestressing force and diameter and spacing of tendons are the base strata strength, traffic conditions, design life and temperature variations;
h) The length of the panel may differ as per lifting and handling convenience, and as per its effect on the development of temperature stresses;
i) The top surface of the panels is to be tinned finished while the side faces and the bottom surface are to be kept smooth;
j) The side surface should be such that they are perfectly matching so that the panels are not eccentric to each other;
k) A nominal gap that might be present between the panels may be filled by a suitable filler material which shall be such that it will avoid any percolation of water to the base of the slab and will facilitate nominal expansion of the panels.

5. On face 9 and 14 of the panel as claimed in claim 1 and 4, multiple projections such as 11, are present which facilitate the load transfer between panels and the number of projections in a panel depends upon the major traffic direction and the grade of concrete and the width of each projection might vary between 200 mm to 700 mm and are provided with ducts such as 12 for passing rod 15.

6. For preparing the Pre-tensioned Precast Concrete Panel as claimed in claim 1:

a) Pre-tensioning bed is to be prepared according to the number and size of panels to be casted;
b) Number of mold needs to be prepared as per the site requirement by referring Figure 6 and Figure 8;
c) The pre-tensioning of tendons is to be performed using a suitable pre-tensioning mechanism, available commercially;
d) Concreting of the required grade is to be done (min. M40) in the mold 30 and 20 wherein care needs to be taken to keep the ducts 21, 22, 28 and 29 free from excessive concrete and to keep it in place while concreting;
e) Tendons 19 are cut, as soon as the concrete has gained sufficient strength;
f) When further strength has been gained by concrete, the panels are lifted and inserted into the curing pond;
g) After concrete has gained the required strength, the panels are to be lifted from the curing tank and stacked on a suitably leveled surface.