Internal Guidance Submitted By:

K. VENKAT ABDUL AZIZ

(13QH1A0101)

HOLY MARY INSTITUTE OF TECHNOLOGY & SCIENCE

DEPARTMENT OF CIVIL ENGINEERING

A

Technical Seminar

Report

On

NOISE REDUCTION IN PAVEMENT MADE

OF RUBBERIZED BITUMINOUS TOP LAYER

Content • Introduction

• History of rubberized bituminous top layer

• Classification of bituminous rubber in top layer

• Preliminary mix design of rubberized binders

• Advantages

• Disadvantages

• Stabilization and aggregates

• Conclusion

• References

INTRODUCTION

Noise reduction in pavement made of rubberized bituminous top layer also known as asphalt rubber or just rubberized asphalt, is pavement material that consists of regular asphalt concrete mixed with crumb rubber made from recycled tires.

Asphalt rubber is the largest single market for ground rubber in the United States, consuming an estimated 220,000,000 pounds (100,000,000 kg), or approximately 12 million tires annually.

History of rubberized bituminous top layer

Pavement material was pioneered by the city of Phoenix, Arizona in the 1960s because of its high durability.

After that- California, Florida, Texas, and South Carolina are also started asphalt rubber.

In 2012, the State of Georgia issued a specification for the use of rubber-modified asphalt for bituminous top layer to control the noise.

This tests are currently underway in other parts of the United States to determine the durability of rubberized bituminous top layer asphalt.

Classification of bituminous rubber mixing in top layer

Hot-mix asphalt (HMA),

Cold-laid plant mix (CLPM),

Stone Matrix-in-place or road mix asphalt (SMA),

Penetration macadam (PM).

Fig.3- Cold-laid plant mix

(CLPM)

Fig.4- Penetration macadam (PM)

Fig.1- Fig.2-

Preliminary mix design of the rubberized binders are-

Relatively low viscosity, so as to compact easily.

Elasticity as common elastromer binder.

Penetration and R&B (Ring & Ball) test similar to the common elastomeric binder.

To be as homogeneous as possible (which means very fine rubber particles included).

Advantages Resistance to permanent deformation.

Good durability due to high binder content.

Good flexibility and resistance.

Good low temperature performance.

More economical in the long term.

Provide friendly and safety features including improved skid resistance on wet pavement of top layers.

Reduced noise and control traffic.

Reduced reflection cracking.

Disadvantages

Increased cost associated with higher binder and filler contents, and additive.

Possible delays in opening to traffic.

Initial skid resistance may be low.

High filler content may result in reduced productivity.

The initial costs of 20-40% higher than conventional dense graded mixtures.

Give less rut depths in comparison to that occurring in a dense friction.

Stabilization

This can happen while the mix is in the HMA storage silos, trucks for transporting and during placement.

Mix drain down is usually combated by adding stabilizing additives. It can be organic or mineral fibers or polymers.

Stabilize the mixture and tend to thicken or bulk the bitumen to prevent binder run-off from the aggregate.

They ensure the homogeneity of the mixture. Aggregate interlock and particle friction are maximized and gives the structure its stability and strength.

Fig. 5- Major components of SMA mixture

Stone Matrix Asphalt Composition

SMA is a blend of crushed coarse aggregate, crushed fine

aggregate (or sand), mineral filler, bitumen binder and stabilizing

agent. These major components

Of SMA mixtures are shown in

Fig.5.

Stone skeleton mixture that,

when compacted, provides the

gap-graded stone-on-stone

structure to carry heavy traffic

loads, prevent rutting, and

provides long term durability.

SMA Aggregate

Selection of materials is important in SMA design. The coarse aggregate should be a durable, fully crushed rock with a cubicle shape .

Fine aggregate should be

at least 50% crushed. Filler

Can be ground limestone

rock, hydrated lime or

flyash.Fig.6- SMA aggregate skeleton

Binder

In rubberized bituminous top layer, bituminous asphalt contains more binder than conventional dense graded mixes, with percentages ranging from about 6.0% to 7.5%.

The performance of the mix is usually enhanced with polymers and fibers.

Polymer modified binders can be used to give even greater deformation resistance.

Additives

• There are many additives in the market including cellulose, mineral rock, wool fibres, glass fibres, siliceous acid (artificial silica), rubber powder and rubber granules and polymers.

• Additives have been introduced into SMA mixes to alleviate the drain down and bleeding problems.

Bituminous Asphalt Properties

• It is a hot mixture with a relatively large proportion of stones and a substantial quantity of bitumen and filler.

•The main concept of having a gap gradation of 100% crushed aggregates is to increase the pavement’s stability through interlock and stone-to-stone contact.

• This mixture is designed to have 3–4% air voids

and relatively high bitumen content due to the high

amount of voids in the mineral aggregate.

• The mixture contains high filler content (10%

passing the 0.075-mm sieve), and a polymer in the

bitumen, or fibre (cellulose or mineral) in the mixture

to prevent the drainage of bitumen.

• This mixture has a surface appearance similar to

that of an open graded friction course; however it

has low in-place air voids similar to that of a dense

graded HMA

Designed and constructed SMA can be enumerated as:

The stone skeleton, with its high internal friction, will give excellent shear resistance.

The binder rich, void less mastic will provide good durability and good resistance to cracking.

The very high concentration of large stones, three to four times higher than in a conventional dense graded mixture will give superior resistance to wear.

The rough surface texture than that of dense graded mixture will assure good skid resistance and proper light reflection.

The surface texture also provide anti-splash features during wet and rainy conditions.

Reduce hydroplaning which results from water draining through the voids in the matrix.

The increased durability of the SMA mixtures can be attributed to thick film thickness and the high binder content .

CONCLUSION In recent years there has been a great and continuous

effort to utilize EOL tires that are being stockpiled world wide. The main research query of bituminous layer made of rubberized dense-graded bituminous mixture, implemented for the first time in Greece, through a pilot applications.

In present research, unique for Greece is that rubberized bituminous mixtures could be a good solution for the re-surfacing of any street which is in poor condition, since not only does it reduces noise generation, but it also provides more durable pavements that are less susceptible to the effects of temperature, while maintaining the noise reduction even after 8 months of operation. Furthermore, the inventory and mapping of road network.

References

www.google.com

www.wikipedia.com

www.bitumin.techno.edu.in

www.ibrp.usa.in

www.rawnauae.com

www.icess.uk.in

Thanks