PRESENTATION ON

ASPHALT AND ASPHALT RECYCLING

BYENGR. ANDREW .A. ONOJA (MNSE)

TO THE ENVIRONMENT DIVISION

OFNIGERIA SOCIETY OF ENGINEERS (NSE),

ABUJA

17TH AUGUST, 2016

WHAT IS AN ASPHALT?* A mixture of dark bituminous pitch with sand or gravel, used for surfacing roads, flooring, roofing, etc.* Asphalt concrete pavement mixes are typically composed of approximately 5% asphalt/bitumen cement and 95% aggregates (stone, sand, and gravel). Due to its highly viscous nature, asphalt/bitumen cement must be heated so it can be mixed with the aggregates at the asphalt mixing facility.* Asphalt pavement refers to any

paved road surfaced with asphalt.

AREAS OF ASPHALT APPLICATIONS:Although asphalt is mainly used for paving roads, it can also be used for various other purposes. it can be found in the following sectors:

i. Transportation (e.g. roads, railway beds or airport runways, taxiways, etc.)ii. Recreation (playgrounds, bicycle paths, running tracks, tennis courts...)iii. Agriculture (barn floors, greenhouse floors...)iv. Industrial (ports, landfill caps, work sites...)v. Building construction (floorings...)

TYPICAL AREA OF APPLICATION – AN AIRPORT RUNWAY.

BASIC COMPONENTS OF AN ASPHALT

(a) Bitumen (b) Aggregates (Fine and Coarse) (c) Additives  

The major tests to be conducted on the bitumen include: * Penetration Test * Flash/Fire Point Test * Solubility Test *Ductility Test * Specific Gravity Test

* Viscosity Test

The major tests on the Aggregate include the following:* Aggregate-Crushing-Value,(ACV) * Aggregate-Impact-Value,(AIV) * Sieve-Analysis,(Gradation) *Specific-Gravity * Aggregate Abrasion Value (AAV)

The major tests to be conducted on the prepared Asphalt either as Quality Control (QC) or Quality Assurance,(QA):

* Marshall-test -Density -Stability - Flow

* Extraction test - Grading - Bitumen Content.

TWO COMMON TYPES OF ASPHALT• WEARING COURSE• BINDER COURSE

TWO COMMON TEMPERATURE-BASED ASPHALT• HOT MIXED, HOT ROLLED ASPHALT (HOT ASPHALT)• HOT MIXED, COLD ROLLED ASPHALT (COLD

ASPHALT)

FEDERAL MINISTRY OF WORKS SPECIFICATION      % BY WEIGHT PASSING    

Sieve Size

  BINDER COURSE WEARING COURSE31.8mm   100   100  

25mm 90 - 100 100  

19.00mm 70 - 90 100  

12.50mm 55 - 80 85 - 100

9.50mm 47 - 70 75 - 92

6.30mm 40 - 60 65 - 82

2.36mm 27 - 45 50 - 65

1.18mm 20 - 34 36 - 51

0.6um 14 - 27 26 - 40

0.3um 8 - 20 18 - 30

0.15um 5 - 15 13 - 24

0.075um 2 - 7 7 - 14

Bitumen Content (%) 4.5 - 6.5 5.0 - 8.0

Voids in Mix (%) 3.0 - 8.0 3.0 - 5.0

Marshall Stability(kg)  Not less than 3.5KN  Not less than 3.5KNMarshall Flow(mm) 2 - 6 2.0 - 4.0Voids Filled with Bitumen 65 - 72 75 - 82

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FERMA ASPHALT PLANT, KUJE ABUJA

DISCHARGING ASPHALT FROM

SILO INTO TRUCK

COLD ASPHALT

FERMA Cold asphalt

100% made in Nigeria

30-ton stockpile of FERMA Cold Asphalt

100% made in Nigeria

WHAT IS RAP?RAP stands for Reclaimed Asphalt

Pavement. The state of Illinois in USA has been recycling Reclaimed Asphalt Pavement (RAP) material into hot-mix asphalt (HMA) since 1980. The Illinois Department of Transportation's current method of RAP HMA design provides 100% contribution for the residual asphalt binder from the RAP based on solvent extractions. This means that the amount of virgin asphalt binder is reduced by the full amount of asphalt binder in the RAP for the percentage specified.

• Recycling Hot Mix Asphalt (HMA) material results in a reusable mixture of aggregate and asphalt binder known as Reclaimed Asphalt Pavement (RAP).

• Recycling of asphalt pavements is a valuable approach for technical, economical, and environmental reasons (Kennedy et al. 1998).

• Using RAP has been favored over virgin materials in the light of the increasing cost of asphalt, scarcity of economic resources, and the pressuring need to preserve the environment.

• Many countries have reported significant savings when RAP is used (Page and Murphy, 1987).

• Considering material and construction costs, it was estimated that using reclaimed HMA pavement provides a saving ranging from 14 to 34% for a RAP content varying between 20 to 50% (Kandhal and Mallick, 1997).

• For this analysis, when we consider the current cost of HMA at N20,000 per ton, it saves between N4,000 to N10,000 per ton, which can only be considered as an indicator of the true savings when RAP is used at the present time of Economic Recession now in Nigeria.

WHY LIKE THIS?THIS IS ‘TECHNICAL

MADNESS’

A MILLING/RECYCLING PROJECT IN KADUNA – ZARIA ROAD IN 2012

MILLED SURFACE

STOCK PILE OF MILLED ASPHALT – RAP UP TO 6000TONS

HOT ASPHALT RECYCLER

FEATURES 100% MOBILE MIX BOTH VIRGIN AND SCARIFIED ASPHALTIC PAVEMENT(RAP) TIP AND DISCHARGE HMA

RAP GRADING IN A QUARRY SITE

RAP STOCKPILED FROM QUARRY; READY TO BE RECYCLED.

SUMMARY OF THE CYCLING PROCESS

CRITICAL ECONOMIC ROUTES

LOTS OF SAVINGS IN RECYCLED ASPHALT.

THANK YOU FOR LISTENING

My contacts: Engr. A. A. Onoja (MNSE)

Phone: +2348035978662Email: elandyin@yahoo.com