Claims:I claim:-

1. An interface layer between concrete pavement slab and sub-base (DLC- Dry lean concrete layer) or Sub-grade by using Polyurethane foam and polythene sheet which is composed of three materials/ components Polyurethane foam, polythene sheet and burnt waste oil/emulsion from vehicles, which together will act as a layer which will be-bond/ decouple pavement slab and DLC (Sub-base) or Sub-grade.

2. In the layer as claimed in claim 1 depending on the available dimensions of pavement panel required sections of Polyurethane foam /sheet and Polythene sheets must be prepared.

3. Dimension of layer as claimed in claim 1 will be as such, width of layer equal to the width of pavement and length equals to 25% of distance between transverse joint from both ends of transverse joint wherein:
a) Once the required dimensions of elements are obtained preparation of interface/separation/de-bonding layer is started;
b) On a plane, firm and clean ground initially Polythene sheet of required size is placed over which waste burnt oil/emulsion is applied with the help of soft brush;
c) This layer forms the bottom face of interface layer;
d) After effective application of waste/burnt oil/emulsion over Polythene sheet next layer of interface layer is i.e. Polyurethane foam /sheet must be placed over it;
e) To hold all the elements of interface layer together coconut ropes or binding wires or ropes of waste plastic may be used at four corners and at center of each edge;
f) After placing Polyurethane foam /sheet layer the top layer of interface layer is placed over Polyurethane foam /sheet layer;
g) Care must be taken to apply waste burnt oil/emulsion on one of the face of Polythene sheet which will be in contact with Polyurethane foam /sheet;
h) After following above mentioned procedure for preparing interface/separation/de-bonding layer, we will be in position to place it over DLC (Sub-base) or Sub-grade;
i) Placement procedure of interface layer is varies on DLC (sub-base) and Sub-grade (soil media).
, Description: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
Interface layer between concrete pavement slab and sub-base (DLC) or Sub-grade

2. APPLICANT
Sr. No Name Nationality Address
1 Prof. Ram Meghe institute of technology and research Badnera Indian Prof. Ram Meghe institute of technology and research Badnera, Anjangaon Bari road, Badnera, Amravati- 444701

3. PREAMBLE TO THE DESCRIPTION

COMPLETE
Following specification particularly describes the invention and the manner in which it is to be performed.

4. DESCRIPTION.

Technical field of invention:

Present invention in general relates to a method and technique to obtain an interface layer between concrete pavement slab and sub-base (DLC) or Sub-grade by using Polyurethane foam and polythene sheet and in particular to a method to enhance the performance of concrete pavement.

Prior art:

Pavements are subjected to repeated traffic loading throughout their service life. In concrete pavements, the repeated application of traffic loads along with temperature variation may lead to initiation of cracks at highly stressed location. The cracks propagate through the pavement which may finally lead to failure of pavements due to fatigue. Curling stresses results from temperature differential between the top and bottom of a pavement. This tendency to curl induces stress in the pavement as the pavement is restrained by its weight and support pressure from sub-grade. Temperature stresses can also occur in pavements as a result of uniform temperature changes that cause the slab to contract or expand. There is an overall expansion and contraction of the pavement slab due to uniform temperature rise and fall in the concrete pavements. Since, the pavement slab is in contact with soil sub-grade or the sub-base the pavement movements are restrained due to the friction between the bottom layer of the pavement and the soil layer.

CN 104652220 A discloses a construction method of an anti-crack concrete pavement. The construction method is characterized by comprising the following construction steps: (1) carrying out pavement base construction; (2) installing a curbstone; (3) drilling a preformed hole on the curbstone, wherein the diameter of a preformed hole is 3-5 mm longer than the diameter of a cold-drawn low-carbon steel wire; (4) installing a prestress tensioning base; (5) after the cold-drawn low-carbon steel wire penetrates through the preformed hole of the curbstone, fixing the cold-drawn low-carbon steel wire on the side surface of the curbstone by using an anchoring piece; (6) tensioning the cold-drawn low-carbon steel wire; (7) pouring concrete: erecting a simple steel bar stool frame before pouring the concrete, wherein a worker and a machine are prevented from contacting with a steel wire during construction, thus reducing the stress loss of the steel wire; (8) shearing the steel wire: shearing the steel wire after the finally poured concrete reaches the design strength of 70%; and (9) sealing the hole of the curbstone: blocking a gap positioned between the curbstone and the cold-drawn low-carbon steel wire by using expanded high-strength cement paste. The construction method disclosed by the invention has the advantages of good anti-crack effect and low cost.

US 9284694 B2 discloses Polyurethane based roadway forming. Provided herein are roadways containing polyurethane materials. A roadway includes a base layer of a compacted in situ material and/or a wear layer disposed on the base layer. One or both of these layers may include the polyurethane material to bind other components in the layers and to form more robust and durable roadway structures capable of withstanding operating loads of the roadway. In some embodiments, the polyurethane material is added to the wear layer by mixing in situ soil and/or foreign aggregate with polyurethane material or by dispensing the polyurethane material over the existing partially formed wear layer. The base layer may or may not include a polyurethane material. The type, concentration, distribution, and processing of the polyurethane material in the wear layer may be the same or different than that in the base layer.

CN 100340720 C discloses construction method for large scale high-performance cement concrete road panel. The invention describes a method for the construction of large-size cement concrete panel construction support grassroots pressure treatment should be established at the seamless interconnectivity template, the concrete mix, there should be fiber, water reducer and expanders in at least one of the concrete mix from the mixer discharge to paving, vibration, and do mention pulp surface, should be completed at a temperature of 5 ℃ -35 ℃ situation; when concrete paving wind speed 16Km / h, relative humidity of 80-90% to take secondary vibrators way, wiping surface should be 3-4 times, using secondary slit method, surface texture spray after treatment using membrane plus a protective layer conservation. This construction method ensures the quality of the pavement, but also reduces the seam between the plates, which greatly reduces the chance of seam water and foreign matter from the pavement edge and cause damage and reduce the cost of routine maintenance of concrete pavement, increasing durability, extended service life.

WO 2014105410 A1 discloses methods for reducing asphalt pavement thickness, increasing aggregate-to-aggregate contact of asphalt paving materials, and improving low temperature cracking performance of asphalt paving materials. Methods for reducing asphalt pavement thickness, for fabricating asphalt paving material with increased aggregate-to-aggregate contact points, and for fabricating asphalt paving materials with improved low temperature cracking performance are provided. A method for reducing asphalt pavement thickness includes combining base asphalt, an oxidized polyolefin, and an aggregate to form an asphalt paving material. A layer of the asphalt paving material is deposited on a substrate layer and compacted to a thickness that is less than a thickness of a compacted asphalt paving material formed of the aggregate and the base asphalt with no oxidized polyolefin while achieving the same amount or less of high temperature rutting than the compacted asphalt paving material formed of the aggregate and the base asphalt with no oxidized polyolefin.

CN 101857401 B discloses self-inflow type semi-flexible composite pavement and construction method thereof. The invention relates to a semi-flexible composite pavement of which mixed cement slurry can automatically flow in holes of an asphalt mixture in a construction process. The composite pavement comprises an open-graded macro-porous asphalt mixture structure layer and pavement mortar which is filled in the holes of the macro-porous asphalt mixture, wherein the pavement mortar comprises 30 to 50 percent cement, 20 to 40 percent of sand, 2 to 4 percent of organic binder, 10 to 20 percent of active filler, 3 to 10 percent of shrinkage reducer, 0.2 to 0.5 percent of water reducer, 0.1 to 1 percent of early strength agent and water in an amount of 20 to 28 percent based on the total weight of all the components of the pavement mortar. The composite pavement of the invention has the advantages of high compression strength, short maintenance time, smoothness, compactness, seamlessness, skid resistance, wear resistance, crack resistance, durability and convenient construction. The invention also provides a construction method of the semi-flexible composite pavement. The method comprises the steps of base pavement treatment, open-graded asphalt mixture paving, on-spot pavement mortar stirring and grouting, maintenance and the like. In the construction method of the invention, the mortar is automatically filled in the holes of the asphalt mixture according to the gravity per self and high workability and fluidity, so influences which are caused by adopting vibration paving on asphalt frameworks are avoided.

EP 1062394 A4 discloses a method for bonding and creating load transfer capability across a joint between two adjacent concrete members, such as roadway slabs, concrete pipes, and post and beam supports. A slot (16a-16f) is cut perpendicular to the joint and extends into each of the adjoining concrete members. The slot and joint are then integrally filled with polymer concrete to tie the slabs together. A joint tie may be placed in the slot and encased by the polymer concrete when bonding and creating load transfer capability.

Existing methodology / technology provides solution which does not overcome the problems associated with development of frictional stresses. The most common practice of adopting polythene sheet as a de-bonding layer have got lot of problems basically 125 micron sheet is unable to take wear and tear during laying process itself. Polythene sheet gets punctured because of the uneven surface of concrete slab and DLC sub-base, as the aggregates project out from both the surfaces. Owing to which use of polythene sheets is not an effective solution to reduce stresses developed in rigid pavement. De-bonding material alone cannot act as a separation layer as it pose limitation on effective application on the surfaces, hence it must be clubbed with surface element which would help to create a frictionless bond between the de-bonding material and concrete slab or sub-base.

Thus in order to prevents the drawbacks of the existing method and technology there is need to develop an inventive approach and method for reducing the frictional stresses and cracks in concrete pavements and to enhance the performance of the concrete pavements. Hence the present invention designs and develops a novel method and technique to create interface layer between concrete pavement slab and sub-base (DLC- Dry lean concrete layer) or sub-grade by using polyurethane foam and polythene sheet.

Object:

1. Primary object of the present invention is to provide a method to obtain an interface layer between concrete pavement slab and sub-base (DLC) or Sub-grade by using Polyurethane foam and polythene sheet.

2. Another object of the present invention is to provide solution on warping and curling stresses developed in concrete pavement due to non-linear temperature variation.

3. Yet another object of the present invention is that the interface layer will not be puncture due to sufficient thickness of Polyurethane foam.

4. Yet another object of the present invention is to reduce the frictional stress and also contribute to the reduction of cracks in concrete pavement.

5. Yet another object of the present invention is to enhance the performance of concrete pavement by reducing cracking of pavement sections.

6. Yet another object of the present invention is to safeguard the concrete pavement against the effect of wheel (traffic) and environmental (temperature, precipitation) loads.

7. Yet another object of the present invention is to develop an interface / separation/de-bonding layer to minimize the frictional stresses developed on concrete pavement.

8. Yet another object of the present invention is to develop a technology by making use of waste /thrown out materials for improving the performance of concrete pavement.

9. Yet another object of the present invention is to solve the problem associated with disposal of Polyurethane waste (foam/sheet), Plastic waste (sheet) by using effective disposal system.

10. Yet another object of the present invention is to extend the spacing of transverse joint in concrete pavement.

11. Yet another object of the present invention is to increase the construction speed of concrete pavement.

12. Yet another object of the present invention is to economize the construction cost of concrete pavement.

13. Yet another object of the present invention is to provide versatile solution which is user-friendly, eco-friendly and economical to obtain efficient and cost effective concrete pavement.

14. Yet another object of the present invention is to enhance performance and economize concrete pavement by making use of waste materials from various industrial sources.

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 to obtain an interface layer between concrete pavement slab and sub-base (DLC- Dry lean concrete layer) or Sub-grade by using Polyurethane foam and polythene sheet. The interface /separation/sandwiched layer is composed of three materials/ components Polyurethane foam, polythene sheet and burnt waste oil/emulsion from vehicles, which together will act as a layer which will be-bond/ decouple pavement slab and DLC (Sub-base) or Sub-grade. Depending on the available dimensions of pavement panel required sections of Polyurethane foam /sheet and Polythene sheets must be prepared. Dimension of layer will be as such, width of layer equal to the width of pavement and length equals to 25% of distance between transverse joint from both ends of transverse joint. Once the required dimensions of elements are obtained preparation of interface/separation/de-bonding layer is started. On a plane, firm and clean ground initially Polythene sheet of required size is placed over which waste burnt oil/emulsion is applied with the help of soft brush. This layer forms the bottom face of interface layer. After effective application of waste/burnt oil/emulsion over Polythene sheet next layer of interface layer is i.e. Polyurethane foam /sheet must be placed over it. To hold all the elements of interface layer together coconut ropes or binding wires or ropes of waste plastic may be used at four corners and at center of each edge. After placing Polyurethane foam /sheet layer the top layer of interface layer is placed over Polyurethane foam /sheet layer. Care must be taken to apply waste burnt oil/emulsion on one of the face of Polythene sheet which will be in contact with Polyurethane foam /sheet. After following above mentioned procedure for preparing interface/separation/de-bonding layer, we will be in position to place it over DLC (Sub-base) or Sub-grade. Placement procedure of interface layer is varies on DLC (sub-base) and Sub-grade (soil media).

Detailed description:

Proposed novel approach helps to minimize the frictional stresses in addition to warping and curling stresses which are observed due to seasonal / daily temperature variation. Incorporation of a novel interface/sandwiched layer composed of Polyurethane foam, polythene sheet and burnt waste oil/emulsion from vehicles between concrete pavement and (DLC) sub-base or sub-grade helps to resolve the observed problem of initial and post cracking of concrete pavement. Polyurethane foam wastes belong to the white pollution, and affect the living environment [Wenqing yang et al]. In the same way polythene waste creates lot of disposal problem, which is a challenge on researchers, government bodies to search for innovative use of environmental waste that would help to solve disposal problems. Present technology aims to provide versatile solution which is user-friendly, eco-friendly and economical to obtain efficient and cost effective concrete pavement.

A novel technology of providing an innovative separation layer between concrete slab and sub-base or sub-grade by making use of Polyurethane foam and Polythene sheet is proposed. Present technology not only reduces frictional stresses but also provides solution on warping and curling stresses developed in concrete pavement due to non-linear temperature variation. As stated above the increment in frictional stresses is due to non-uniform temperature variation along the thickness and length of concrete pavement. Polyurethane foam is used as a thermal insulator in many engineering applications due to low thermal conductivity of polyurethane foam it behaves as a bond breaker between concrete slab and DLC sub-base. A sufficient thickness of Polyurethane foam sandwiched between polythene sheets creates a interface layer which can adopted as a separation layer between concrete slab and DLC sub-base or sub-grade. To reduce the friction developed on the surface of concrete slab and DLC sub-base or sub-grade, burnt used wastage oil / emulsion from vehicles, trucks, and transformers will be applied on surface of polythene sheets to obtain a smooth surface. The sandwiched layer will act as single unit to reduce the frictional as well as warping and curling stresses. The proposed technology has dual advantages, firstly the roughened surface of concrete slab and sub-base or sub-grade will not be able to puncture the interface layer due to sufficient thickness of Polyurethane foam owing to which frictional stresses will be reduced that will contribute to the reduction of cracks in concrete pavement. Secondly, the effect of non-linear temperature variation due to seasonal changes results in warping and curling stresses. These are the main reason for bottom up and top down cracking observed in concrete pavement which leads to progressive fatigue damage. As Polyurethane foam is used in the sandwiched layer effects of non-linear temperature can be minimized. This results in lesser amount of stresses on concrete pavement. Hence, proposed novel technology will prove to be useful and economical for concrete pavement industry.

A novel interface /separation/sandwiched layer is proposed for concrete pavement which will be incorporated between concrete slab and DLC (Sub-base) or Sub-grade. The interface /separation/sandwiched layer is composed of three materials/ components Polyurethane foam, polythene sheet and burnt waste oil/emulsion from vehicles, which together will act as a layer which will be-bond/ decouple pavement slab and DLC (Sub-base) or Sub-grade. Detail description of the invention is as under,

i. Polythene sheet: This forms the top and bottom surface of the interface/sandwiched layer. A sheet or sheets preferably of width equal to the width of concrete pavement must be used, whereas length of sheet will depend on the length of pavement. Polythene sheet of thickness easily available can be used. For good results Polythene sheet of thickness more than 125 micron shall be adopted. Care must be taken that it must not be punctured before laying on Polyurethane foam. Transparent or white colored sheet must be preferred than black sheet.

ii. Polyurethane foam: This forms the middle part of interface/sandwiched layer. Polyurethane foam /sheet must be sandwiched between two layers of polythene sheet. Width of Polyurethane foam /sheet must be equal to the width of concrete pavement. The length of Polyurethane foam /sheet must be kept as 25% of the length between two successive transverse joint (0.25 x L). Where, L is distance between two transverse joint. This layer must start from end of transverse joint and extend till calculated length (0.25 x L) towards the centre of concrete pavements from either ends of transverse joint. Thickness of Polyurethane foam /sheet must be more than 50 mm. Depending on the design loads the requirement in thickness Polyurethane foam /sheet of can be done. Polyurethane foam /sheet preferably of white/milky white may be used or surface of the foam/ sheet must be covered with white chalk powder.

iii. Burnt waste oil/emulsion: This element of invention is used for surfacing the different layers of interface/sandwiched layer. Burnt waste oil/emulsion from vehicles (two wheelers, four wheelers), trucks, electrical transformers etc is thrown out as a part of waste. Due to the basic ingredients in engine / machine oil it is operative at high temperatures and has performed well. It has added benefit of remaining smooth under critical situations. Hence, application of burnt waste oil/emulsion is an innovative idea to reduce friction among different surfaces of construction elements.

Method/procedure for developing and placing interface/separation/de-bonding layer between DLC (Sub-base) or Sub-grade:
i. Assemblage of required material: Depending on the stretch of the road required quantity must be worked out and material required for a particular patch/area must be kept ready along with the basic elements of concrete road construction.

ii. Preparation of interface/separation/de-bonding layer: As per the design requirements width and spacing of transverse joint in pavement will be available. Depending on the available dimensions of pavement panel required sections of Polyurethane foam /sheet and Polythene sheets must be prepared. Dimension of layer will be as such, width of layer equal to the width of pavement and length of pavement equals to 25% of distance between transverse joint from both ends of transverse joint. Once the required dimensions of elements are obtained preparation of interface/separation/de-bonding layer is started. On a plane, firm and clean ground initially Polythene sheet of required size is placed over which waste burnt oil/emulsion is applied with the help of soft brush. This layer forms the bottom face of interface layer. After effective application of waste/burnt oil/emulsion over Polythene sheet next layer of interface layer i.e. Polyurethane foam /sheet must be placed over it. To hold all the elements of interface layer together coconut ropes or binding wires or ropes of waste plastic may be used at four corners and at center of each edge. After placing Polyurethane foam /sheet layer the top layer of interface layer is placed over Polyurethane foam /sheet layer. Care must be taken to apply waste burnt oil/emulsion on one of the face of Polythene sheet which will be in contact with Polyurethane foam /sheet. After following above mentioned procedure for preparing interface/separation/de-bonding layer, we will be in position to place it over DLC (Sub-base) or Sub-grade.

iii. Placement of interface/separation/de-bonding layer: As the proposed technology can be used on DLC (Sub-base) or Sub-grade (Soil media). Placement procedure varies accordingly. If placement of interface layer is on DLC (sub-base) then placement procedure will be as under,

a. DLC (sub-base) which is supposed to be casted some days earlier has lot of irregularities /surface roughness. To overcome this problem surface of DLC (sub-base) must be made smooth by removing undulations on the surface of DLC (sub-base).
b. On to the prepared/smooth DLC (sub-base) waste burnt oil/emulsion is applied with brush or cloth so that it must be applied evenly covering all area of DLC (sub-base).
c. After application of waste burnt oil/emulsion over DLC (sub-base), prepared interface/ separation / de-bonding layer is placed over DLC (sub-base). Depending on the position of transverse joint interface layer must be placed properly. To make work simpler interface layer of 50% of the length between transverse joint must be prepared, which can be placed on both sides of transverse joint as 25-25%.
d. Once interface layer is placed on its specific location top surface of interface layer is again applied with waste burnt oil/emulsion to reduce the friction between interface layer and concrete slab above it.
e. Concrete is poured over prepared interface layer slowly by slowly so that separation layer may not get hampered.

If placement of interface layer is on Sub-grade (soil media) then placement procedure will be as under,
a. A well prepared and leveled sub-grade (soil media) having CBR (California Bearing Ratio) of more than 8% must be used.
b. On to the prepared sub-grade thick sections of geofoam (thermo Cole) must be used in place of DLC layer. Width of geofoam must be kept more than the width of pavement projecting out by 150 mm on both sides. Geofoam having minimum thickness of 200mm is recommended over sub-grade.
c. Before placement of interface/separation/de-bonding layer top surface of geofoam is applied with waste burnt oil/emulsion. Over this well prepared interface layer is prepared and placed as per the procedure described above. Position as well as preparation of layer will be the same as discussed in earlier points b, c, d and e.
d. Proper care must be taken while pouring concrete over the interface layer, so that interface layer must not get hampered.

Advantages over existing technology:
a. Exiting technology focuses only on reduction of frictional stresses (which is still questionable) by use of polythene sheet or various de-bonding material but the proposed novel technique is a versatile solution over the problems associated with concrete pavement regarding cracking. Proposed novel technique suffices the requirement for consideration of frictional as well as warping and curling stresses arising due to seasonal temperature variation.

b. Polythene sheet or de-bonding materials used in existing technique do not meet the durability aspects of concrete pavement as they get hampered during laying process, whereas their effectiveness is still a question with reference for obtaining perpetual pavements. On the other hand proposed novel technology proves to be effective in regards to design life of pavement. Being a sandwiched interface layer it can hold to tampering during the construction process.

c. As the proposed separation layer (sandwiched) is composed of Polyurethane foam, Polythene sheet and burnt waste oil/emulsion from vehicles, trucks and transformers, all of these materials can be used economically since they are waste materials. Polyurethane foam a good thermal insulating agent is an refusal from many of Air conditioners, fridge’s, cooling machines etc. hence, incorporation of Polyurethane foam in concrete pavement will solve the disposal problem as it is being recycled. Polythene sheet is a plastic waste a threat to the environment hence, addition of polythene sheet in separation layer will prove to be worthy for solving disposal problem. Burnt waste oil being used as an alternative over de-bonding compounds sets a example of using waste material that too on a cheaper side. Hence, existing technology is really economical as compared to the existing solution on the basis of merits of proposed novel technology.

d. Existing process of the constructing rigid pavement require skill labors as the polythene sheet and de-bonding products have to be applied properly. In spite of taking lot of care sheet or compounds would get hampered. Whereas, novel technique proves to be very easy and can be handled by unskilled labors too. Simply the required sizes of sandwiched panels have to be made prior to placement on DLC sub-base or Sub-grade rest of the things will take place as per routine. Hence, proposed novel technology is effective, versatile, eco-friendly and cost effective as in comparison to existing technology.

Additional advantages and modification will readily occur to those skilled in art. 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 by the appended claims and their equivalents.