Chemicals

Steel Slag aggregate

Introduction 01

WhereDoesSteelSlagAggregateComeFrom? 02

Properties 03

SteelSlagAggregateasaRoad-MakingMaterial 04

EnvironmentalSustainability 06

TheLifeCycle 07

Contents

NSL Chemicals started the research on utilisation of steel slag in collaboration with Nanyang Technological University in year 1991. Two years later, the use of steel slag as pavement aggregate material was approved by Road and Transport Division of Public Works Department (currently known as Land and Transport Authority) in Singapore.

Since then, NSL Chemicals has been processing steel slag into a constructional material through a proprietary treatment method in its Singapore and Malaysia plants, achieving a 100% recycling rate.

NSL Chemicals is a regional leader in lime and specialised refractory products manufacturing and a solid waste recycler that includes steel slag processing.

IntroduCtIonThe company has evolved from being a supplier of quicklime and steel scrap to becoming one of the leading Chemical companies in Southeast Asia. With presence in Singapore, Malaysia, Thailand and Indonesia, its clients are located worldwide. Its commitment to bizSAFE Star (Singapore) certifications is in line with its work safety efforts.

NSL Chemicals is a wholly-owned subsidiary of NSL Ltd, a leading industrial group in Asia Pacific that has been listed on Singapore Exchange since 1964.

01

CONTENTS

*D. Lewis. IRON and STEEL SLAG A NON-HAZARD. National Slag Association.

MF 194-5. December 14, 1980.

Steel slag is a by-product of the steelmaking process and is classified as a non-hazardous waste.*

Steel slag, a non-metallic ceramic material, is produced from the reaction between the fluxing agents and the inorganic non-metallic components in steel scrap. During the steelmaking process, the steel slag floats at the top of the molten steel. The hot slag is then collected and delivered to NSL Chemicals.

where does steel slag aggregate Come from?

Through its proprietary treatment method NSL Chemicals processes the steel slag into aggregate that is suitable to be used as construction material for the roads.

Steel slag is generated at a rate of 10-15% from the overall liquid steel output. This significant amount of steel slag if untreated, would be required to dispose in landfill and poses economic and environmental adversities.

02

CONTENTS

Typical Physical Properties of Steel Slag & Granite Aggregate

Parameter Unit SteelSlagAggregate GraniteAggregate

Density oven dried g/cm3 3.31 - 3.51 2.59Density saturated surface dried g/cm3 3.24 - 3.56 2.60

Density apparent (BS812:2) g/cm3 3.34 - 3.69 2.61

Bulk density (BS812:2) loose/compacted g/cm3 1.77 / 1.96

Water absorption (BS812:2) % 0.6 - 1.4 0.39

Flakiness index (BS 812:105.1) % 3 - 16 22

Elongation index (BS 812:105.2) kN 7 - 17 28

Los Angeles Abrasion value (SS73) % 20 - 25 35

Aggregate impact value (BS 812, S112) % 21 - 31 14

Magnesium sulphate soundness (BS EN1367-2) % 0.6 - 2.4 2.1

Polished Stone Value (BS812:114) _ 61 - 64 49Chemical & Physical Properties of Steel SlagTypical chemical compositions of EAF steel slag & granite

Component SteelSlag(wt%) Granite(wt%)

SiO2

Typical Values of Asphalt MixParameter

SteelSlagAggregate

GraniteAggregate

Remarks

Marshall Stability (kN) 20.6 11.0 Superior performance

Marshall Flow (Unit) 3.61 3.85 Within range

Void in Mix (%) 4.98 4 Within range

Wheeltracking (mm/h) 3.7 10 Less deformation & wear

Repeated Load Indirect Tensile Test (Mpa)

3071 2607 Superior performance

Since 1993, steel slag aggregate has been used as road surfacing material in Singapore and it has been found to be extremely advantageous.

With its high angularity, it makes a good aggregate that interlocks, hence providing high rutting resistance. The rough surface texture ensures high polished stone value and high pavement skid resistance.

Steel slags high mechanical strength enhances pavement durability. A hydrophobic material with basic surface chemistry, it has good bonding with asphalt binder, resulting in less stripping and better resistance to moisture on

the roads.

All these result in an increased lifespan of the pavement and safer road conditions, as well as the conservation of natural resources such as granite. Due to the unique properties of steel slag aggregate, it is a preferred construction material for areas with adverse traffic conditions such as road junctions and slip roads on the expressways.

These superior properties of steel slag aggregate in road-making can be found from the table above.

04

steel slag aggregate as a road-makIng materIal

CONTENTS

01. Woodland Road & PIE02. Sungei Kadut St 1 & St 203. Jurong West St 51 Traffic

Junction04. Corporation Road05. Boon Lay Drive Traffic Junction06. International Road & Boon Lay

Way Junction07. AYE Jurong Townhall Exit08. Boon Lay Way Traffic Junction09. Upper Thomson & Yio Chu

Kang Road10. Ang Mo Kio Ave 3 & 8

11. Thomson & Moulmein Road12. Balestier & Whampoa Drive

Road13. Ayer Rajah Expressway14. St Andrews Road15. Bedok South Ave 1 & Marine

Parade Road T-Junction16. East Coast Road & Siglap Road

Junction17. Chai Chee Drive & Changi Road

Junction18. Upper East Coast & Bedok

Road

05

1103

0410

05

0608

09

01

12

02

14

0715

16 1718

13

More than 1.3 million tons of steel slag aggregate have been paved on Singapore roads over the last 15 years.

roads that use steel slag aggregate In sIngapore

CONTENTS

Today, NSL Chemicals is estimated to have saved over 520,000 m3 of landfill sites in Singapore through recycling steel slag into superior aggregate materials

Carbon Footprint of Steel Slag and Granite Aggregates

0.05000

0.04000

0.03000

0.02000

0.01000

0.00000

KgC

O2e

Steel Slag Granite

Transportation

Electricity

Diesel

Explosives

envIronmental sustaInabIlIty

06

Apart from being a superior aggregate material, steel slag aggregate offers exceptional environmental benefits. These include:

Conservation of natural resources

Reduction of waste from steel-making

Reduction of carbon footprint

CONTENTS

the lIfe CyCle

07

Singapore Road

Slag processing Road-making

Steel slag HMA wearing course

Steel slag Hot Mix Asphalt (HMA)

Steel slag HMA surface

Graded steel slag aggregate

Steel by-product

Hot slag Solidified raw slag

Below is a diagram that shows how roads are made by steel slag aggregate. The blue arrows indicate where NSL Chemicals plays a part in!

CONTENTS

NSL Chemicals Ltd26 Tanjong Kling Road, Singapore 628051

Tel : 65-6513 6900

Fax : 65-6265 9942

Email : sales@nslchemicals.com.sg

www.nslchemicals.com.sg

Reg No. 196800220K

RST Teknologi Sdn Bhd

2723, Lorong Perusahaan 12, Prai Industrial Estate, 13800, Prai Pulau Pinang , Malaysia

Tel : 60-4-3983287

Fax : 60-4-3983385

Chemicals

ContaCt ussubsIdIary