Title of Invention	"AN IMPROVED BITUMINUOUS MIXTURE AND A PROCESS FOR PREPARATION THEREOF"
Abstract	This invention relates to an improved bituminous mixture used in the construction of road/highway/express way etc comprising of 20-40% of fine aggregate, 2-10% of filler, 4.0-6.0% of bitumen and coarse aggregate. Further, this invention relates to a process of laying comprising steps of cleaning surface, application of tack coat, application of rejuvenating coat comprising 0.2-2.0% of bitumen by weight of overlying mixture and laying a mixture followed by compaction.

Title of Invention

"AN IMPROVED BITUMINUOUS MIXTURE AND A PROCESS FOR PREPARATION THEREOF"

Abstract

This invention relates to an improved bituminous mixture used in the construction of road/highway/express way etc comprising of 20-40% of fine aggregate, 2-10% of filler, 4.0-6.0% of bitumen and coarse aggregate. Further, this invention relates to a process of laying comprising steps of cleaning surface, application of tack coat, application of rejuvenating coat comprising 0.2-2.0% of bitumen by weight of overlying mixture and laying a mixture followed by compaction.

Full Text	FIELD OF INVENTION This invention relates to an improved bituminous mixture and a process of laying the mixture. It is particularly used in the construction of road/Highway/Expressway without restricting its use to the same. PRIOR ART Currently available bituminous mixtures, being used in the wearing course of flexible /Semi-Rigid pavement of roads, have the following composition of materials: 1. Coarse Aggregate 2. Fine Aggregate 3. Filler 4. Bitumen. The above mentioned materials are suitably proportioned according to standard specifications adopted in practice so as to make a durable road at minimum cost without compromising its serviceabilty. With standard specifications the wearing course can provide the desired level of service for a period of 4-6 years in case of new construction and 3-5 years in case of periodical repair. To increase life time of Bituminous road, use of more Bitumen is suggested. However, the disadvantage associated with the same is that, it leads to rutting failure and increase in initial cost on the other hand if less Bitumen is used then life span of the road is reduced. OBJECTS OF THE INVENTION An object of the present invention is to propose an improved bituminous mixture and a process of laying the mixture used particularly for the construction of Road/Highway/Expressway, resulting in long life time of the same. Another object of the present invention is to propose an improved bituminous mixture and a process of laying the mixture thereof used particularly for the construction of Road/Highway/Expressway which is cost effective. Still another object of the present invention is to propose an improved bituminous mixture and a process of laying the mixture used particularly for the construction of Road/Highway/Expressway, in which maintenance cost is considerably reduced as compared to the known art. STATEMENT OF INVENTION According to this invention, there is provided an improved bituminous mixture used in the construction of road/highway/express way etc comprising of 20-40% of fine aggregate, 2-10% of filler, 4.0-6.0% of bitumen and coarse aggregate. Further, according to this invention there is provided a process of laying comprising steps of cleaning surface, application of tack coat, application of rejuvenating coat comprising 0.2-2.0% of bitumen by weight of overlying mixture and laying a mixture followed by compaction. DETAILED DESCRIPTION OF THE INVENTION This invention provides an improved Bituminous mixture comprising of the following: Fine Aggregate -> 20-40% Filler -> 2-10% Bitumen -> 4.0-6.0% Coarse aggregate Fine aggregate is sand. Filler is such as lime, cement, stone dust as defined in the specification. Bitumen is preferably having penetration value of 50-100 and coarse aggregate is such as crushed stone. Proportions of the above said materials have been optimized so as to achieve the maximum density and minimum voids up to certain limit. So that, the problems of rutting as well as cracking leading to failure of wearing course are minimal and also the life of wearing course is increased. One additional material may optionally be provided in the composition to act as reinforcement, which is such as steel, fibrefalt, recron 3s etc. or any non biodegradable material which can take tensile stress to further enhance the life. Specifications for individual materials. Angularity of fine aggregate should be within limits as prescribed in super pave mix design for flexible pavements or manufactured sand should be used as fine aggregate. Maximum coarse aggregate size should not be greater than half of the layer thickness in case of mixtures used for wearing coarse. For all other materials latest prevailing specifications as prescribed by M.O.R. T 8B H for bituminous mixtures or any other government/semi government organization can be used. Proportioning of materials i.e. coarse aggregate, fine aggregate and filler Combined grading of the materials as mentioned above is determined by the following equation:- (Equation Removed) Where P is the percentage passing any given sieve size n varies from 0.40 to 0.50 for sieves of size greater than 2.36mm. For smaller sieves i.e. size less than or equal to 2.36mm it varies from 0.45 to 0.55 subject to the condition that n value for smaller sieves should be greater than that adopted for larger sieve i.e. Sieve size greater than 2.36mm. Best recommended value for n is 0.47 for larger sieves and 0.48 for smaller sieves. d is the sieve size for which P is to be determined. D is equal to approximately half the layer thickness in case of wearing coarse. For other layers it should be nearly 0.6 times the layer thickness. Determination of bitumen content Marshall stability test as prescribed in Asphalt Institute manual MS-2 with latest amendments can be used for determination of bitumen content. Alternatively, any other hot mix design method can be used. However, the range of air voids in the mixture should be 4% to 9% which was 3-6% in known art. When the mix is laid after the end of summer season but before the end of winter season, the air void range should be from 4% to 7%. For other period it should be from 5% to 9%. The high range of air voids is for rapid gain of strength of mixture to resist secondary compaction during the first few months of opening to traffic. Application of Rejuvenating Coat:- It involves sprinkling a layer of bitumen on the tack coated surface and involves the following steps:- Step 1:- Bitumen having penetration value in the range of 60 to 100 as determined by penetration test should be used. Preferable range for penetration value is 80 to 100. After compaction, the void space is 3-8%. Due to secondary compaction it is again filled up by the underlying bitumen in the rejuvenating coat to reach a value of 1.5% to 2.5% at the end of 3 years of use. This increases life span of the construction using said mixture. Step 2:- Quantity of bitumen to be sprinkled for this coat varies from 0.2% to 2.0% of the weight of overlying layer. Step 3:- Procedure for sprinkling Bitumen for the Rejuvenating coat can be sprinkled in the form of big droplets with spacing within a range of 2.0 cm to 7.0 cm. OR It can be sprinkled in the form of a continuous film with an unsprinkled space of 5cm to 15cm in a direction normal to the direction of surface drainage. The film width should be between 15cm to 60cm OR When either of the above two procedures cannot be adopted, it can be applied in the form of a continuous film without any unsprinkled space or it can be sprinkled in the form of a number of continuous jets, flowing on to the proposed surface in a direction normal to the surface drainage direction of water. The spacing between the jets should not be less than 5cm and not more than 20cm. If Rejuvenating coat is to be provided as a continuous film then bitumen content is increased in tack coat provided the type of bitumen used for tack coat and Rejuvenating Coat is same. The process of laying the mixture comprising of cleaning the surface, applying tack coat and rejuvenating coat followed by laying of said mixture and compaction. However, in one embodiment of the process, a mixture of tack and rejuvenating coat can be applied on the clean surface. After which the mixture is applied Tack Coat serves the purpose of glue. Finally, compaction is carried out. Compaction can be continued till the pavement temperature is ten degrees above the softening point of bitumen used in the mixture but with light weight rollers for temperature below the prevailing specification for compaction. Compaction level should be 95% to 98% of the laboratory density of mix. The present invention is also applicable if base course is of bituminous mixture. It is to be noted that the present invention is susceptible to modifications, adaptations and changes by those skilled in the art. Such variant embodiments employing the concepts and features of this invention are intended to be within the scope of the present invention, which is further set forth under the following claims:- WE CLAIM: 1. An improved bituminous mixture used in the construction of road/highway/express way etc comprising of 20-40% of fine aggregate, 2-10% of filler, 4.0-6.0% of bitumen and coarse aggregate. 2. A process of laying comprising steps of cleaning surface, application of tack coat, application of rejuvenating coat comprising 0.2-2.0% of bitumen by weight of overlying mixture and laying a mixture followed by compaction. 3. An improved bituminous mixture and a process as claimed in claim 1 or 2, wherein said mixture may be provided with reinforcement/any non biodegradable material. 4. An improved bituminous mixture and a process as claimed in claim 1 or 2 wherein said bitumen is preferably having penetration value of 50-100. 5. A process as claimed in claim 2, wherein said mixture comprising of 20-40% of fine aggregate, 2-10% of filler, 4.3-5.5% of bitumen and coarse aggregate. 6. A process as claimed in any of the preceding claims, wherein said mixture is having air voids of 4-9% such as herein described. 7. A process as claimed in any of the preceding claims, wherein said rejuvenating coat comprising of bitumen having penetration value of 60-100 preferably 80-100 and quantity of 0.2 -1.0% of the weight of overlying layer. 8. A process as claimed in claim 7, wherein bitumen for the rejuvenating coat is sprinkled in the form of big droplets with spacing of 2-7cm. 9. A process as claimed in claim 7, wherein bitumen for the rejuvenating coat is sprinkled in the form of a continuous film with an unsprinkled space of 5-15cm in a direction normal to the direction of surface drainage wherein the film width is 15-60cm. 10. A process as claimed in claim 7, wherein said rejuvenating coat can be applied as continuous film by increasing bitumen content in tack coat wherein the type of bitumen used for the tack coat and rejuvenating coat is same. 11. An improved bituminous mixture and a process of laying the mixture substantially as herein described.

Full Text

FIELD OF INVENTION
This invention relates to an improved bituminous mixture and a process of laying the mixture. It is particularly used in the construction of road/Highway/Expressway without restricting its use to the same.
PRIOR ART
Currently available bituminous mixtures, being used in the wearing course of flexible /Semi-Rigid pavement of roads, have the following composition of materials:
1. Coarse Aggregate
2. Fine Aggregate
3. Filler
4. Bitumen.
The above mentioned materials are suitably proportioned according to standard specifications adopted in practice so as to make a durable road at minimum cost without compromising its serviceabilty. With standard specifications the wearing course can provide the desired level of service for a period of 4-6 years in case of new construction and 3-5 years in case of periodical repair.

To increase life time of Bituminous road, use of more Bitumen is suggested. However, the disadvantage associated with the same is that, it leads to rutting failure and increase in initial cost on the other hand if less Bitumen is used then life span of the road is reduced.
OBJECTS OF THE INVENTION
An object of the present invention is to propose an improved bituminous mixture and a process of laying the mixture used particularly for the construction of Road/Highway/Expressway, resulting in long life time of the same.
Another object of the present invention is to propose an improved bituminous mixture and a process of laying the mixture thereof used particularly for the construction of Road/Highway/Expressway which is cost effective.
Still another object of the present invention is to propose an improved bituminous mixture and a process of laying the mixture used particularly for the construction of Road/Highway/Expressway, in which maintenance cost is considerably reduced as compared to the known art.
STATEMENT OF INVENTION
According to this invention, there is provided an improved bituminous mixture used in the construction of road/highway/express way etc comprising of 20-40% of fine aggregate, 2-10% of filler, 4.0-6.0% of bitumen and coarse aggregate.

Further, according to this invention there is provided a process of laying comprising steps of cleaning surface, application of tack coat, application of rejuvenating coat comprising 0.2-2.0% of bitumen by weight of overlying mixture and laying a mixture followed by compaction.
DETAILED DESCRIPTION OF THE INVENTION
This invention provides an improved Bituminous mixture comprising of the following:
Fine Aggregate -> 20-40%
Filler -> 2-10%
Bitumen -> 4.0-6.0%
Coarse aggregate
Fine aggregate is sand. Filler is such as lime, cement, stone dust as defined in the specification. Bitumen is preferably having penetration value of 50-100 and coarse aggregate is such as crushed stone.
Proportions of the above said materials have been optimized so as to achieve the maximum density and minimum voids up to certain limit. So that, the problems of rutting as well as cracking leading to failure of wearing course are minimal and also the life of wearing course is increased.
One additional material may optionally be provided in the composition to act as reinforcement, which is such as steel, fibrefalt, recron 3s etc. or any non biodegradable material which can take tensile stress to further enhance the life.

Specifications for individual materials.
Angularity of fine aggregate should be within limits as prescribed in super pave mix design for flexible pavements or manufactured sand should be used as fine aggregate. Maximum coarse aggregate size should not be greater than half of the layer thickness in case of mixtures used for wearing coarse. For all other materials latest prevailing specifications as prescribed by M.O.R. T 8B H for bituminous mixtures or any other government/semi government organization can be used.
Proportioning of materials i.e. coarse aggregate, fine aggregate and filler
Combined grading of the materials as mentioned above is determined by the following equation:-
(Equation Removed)
Where
P is the percentage passing any given sieve size
n varies from 0.40 to 0.50 for sieves of size greater than 2.36mm. For smaller sieves i.e. size less than or equal to 2.36mm it varies from 0.45 to 0.55 subject to the condition that n value for smaller sieves should be greater than that adopted for larger sieve i.e. Sieve size greater than 2.36mm. Best recommended value for n is 0.47 for larger sieves and 0.48 for smaller sieves.

d is the sieve size for which P is to be determined.
D is equal to approximately half the layer thickness in case of wearing coarse. For other layers it should be nearly 0.6 times the layer thickness.
Determination of bitumen content
Marshall stability test as prescribed in Asphalt Institute manual MS-2 with latest amendments can be used for determination of bitumen content. Alternatively, any other hot mix design method can be used. However, the range of air voids in the mixture should be 4% to 9% which was 3-6% in known art.
When the mix is laid after the end of summer season but before the end of winter season, the air void range should be from 4% to 7%.
For other period it should be from 5% to 9%.
The high range of air voids is for rapid gain of strength of mixture to resist secondary compaction during the first few months of opening to traffic.
Application of Rejuvenating Coat:-
It involves sprinkling a layer of bitumen on the tack coated surface and involves the following steps:-
Step 1:- Bitumen having penetration value in the range of 60 to 100 as determined by penetration test should be used. Preferable range for penetration value is 80 to 100.

After compaction, the void space is 3-8%. Due to secondary compaction it is again filled up by the underlying bitumen in the rejuvenating coat to reach a value of 1.5% to 2.5% at the end of 3
years of use.
This increases life span of the construction using said mixture.
Step 2:- Quantity of bitumen to be sprinkled for this coat varies from 0.2% to 2.0% of the weight of overlying layer.
Step 3:- Procedure for sprinkling
Bitumen for the Rejuvenating coat can be sprinkled in the form of big droplets with spacing within a range of 2.0 cm to 7.0 cm.
OR
It can be sprinkled in the form of a continuous film with an unsprinkled space of 5cm to 15cm in a direction normal to the direction of surface drainage. The film width should be between 15cm to 60cm
OR
When either of the above two procedures cannot be adopted, it can be applied in the form of a continuous film without any unsprinkled space or it can be sprinkled in the form of a number of continuous jets, flowing on to the proposed surface in a direction normal to the surface drainage direction of water. The spacing between the jets should not be less than 5cm and not more than 20cm. If Rejuvenating coat is to be provided as a

continuous film then bitumen content is increased in tack coat provided the type of bitumen used for tack coat and Rejuvenating Coat is same.
The process of laying the mixture comprising of cleaning the surface, applying tack coat and rejuvenating coat followed by laying of said mixture and compaction. However, in one embodiment of the process, a mixture of tack and rejuvenating coat can be applied on the clean surface. After which the mixture is applied Tack Coat serves the purpose of glue. Finally, compaction is carried out.
Compaction can be continued till the pavement temperature is ten degrees above the softening point of bitumen used in the mixture but with light weight rollers for temperature below the prevailing specification for compaction.
Compaction level should be 95% to 98% of the laboratory density of mix.
The present invention is also applicable if base course is of bituminous mixture.
It is to be noted that the present invention is susceptible to modifications, adaptations and changes by those skilled in the art. Such variant embodiments employing the concepts and features of this invention are intended to be within the scope of the present invention, which is further set forth under the following claims:-

WE CLAIM:
1. An improved bituminous mixture used in the construction of road/highway/express way etc comprising of 20-40% of fine aggregate, 2-10% of filler, 4.0-6.0% of bitumen and coarse aggregate.
2. A process of laying comprising steps of cleaning surface, application of tack coat, application of rejuvenating coat comprising 0.2-2.0% of bitumen by weight of overlying mixture and laying a mixture followed by compaction.
3. An improved bituminous mixture and a process as claimed in claim 1 or 2, wherein said mixture may be provided with reinforcement/any non biodegradable material.
4. An improved bituminous mixture and a process as claimed in claim 1 or 2 wherein said bitumen is preferably having penetration value of 50-100.
5. A process as claimed in claim 2, wherein said mixture comprising of 20-40% of fine aggregate, 2-10% of filler, 4.3-5.5% of bitumen and coarse aggregate.
6. A process as claimed in any of the preceding claims, wherein said mixture is having air voids of 4-9% such as herein described.
7. A process as claimed in any of the preceding claims, wherein said rejuvenating coat comprising of bitumen having penetration value of 60-100 preferably 80-100 and quantity of 0.2 -1.0% of the weight of overlying layer.
8. A process as claimed in claim 7, wherein bitumen for the rejuvenating coat is sprinkled in the form of big droplets with spacing of 2-7cm.

9. A process as claimed in claim 7, wherein bitumen for the rejuvenating coat is sprinkled in the form of a continuous film with an unsprinkled space of 5-15cm in a direction normal to the direction of surface drainage wherein the film width is 15-60cm.
10. A process as claimed in claim 7, wherein said rejuvenating coat can be applied as continuous film by increasing bitumen content in tack coat wherein the type of bitumen used for the tack coat and rejuvenating coat is same.
11. An improved bituminous mixture and a process of laying the
mixture substantially as herein described.

Documents:

http://ipindiaonline.gov.in/patentsearch/GrantedSearch/viewdoc.aspx?id=S5RBUot0ezKKm3IViT69+Q==&loc=+mN2fYxnTC4l0fUd8W4CAA==

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Patent Number

272117

Indian Patent Application Number

1342/DEL/2008

PG Journal Number

13/2016

Publication Date

25-Mar-2016

Grant Date

18-Mar-2016

Date of Filing

04-Jun-2008

Name of Patentee

HARDEEP SINGH

Applicant Address

H.NO. 738-1, BRS NAGAR, LUDHIANA, PUNJAB, PIN-141012. AN INDIAN NATIONAL.

Inventors:

#	Inventor's Name	Inventor's Address
1	HARDEEP SINGH	H.NO. 738-1, BRS NAGAR, LUDHIANA, PUNJAB, PIN-141012. AN INDIAN NATIONAL.

PCT International Classification Number

C08L95/00; C08L91/00

PCT International Application Number

N/A

PCT International Filing date

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1			NA