School of Civil and Environmental Engineering

Research Group of Living Stones @ NTUResearch Group of Living Stones @ NTU

TSB Public Lecture Series on Sustainable Urban Living

8 April 2016, Singapore

Precast Bendable Concrete Paving Slab for

Speedy Road Construction

presented by

Yang En-Hua, PhD, LEED AP

Assistant Professor & Assistant Chair (Academic)

School of Civil and Environmental Engineering

Nanyang Technological University (NTU)

23 November 2017

I3C Symposium on Industrial Infrastructure Research

School of Civil and Environmental Engineering

Research Group of Living Stones @ NTU

Hot-Mixed Asphalt (HMA) Road Surface in Singapore

• Almost all road surface except

for junctions and bus stops

• Subject to heavy vehicles, heat,

and high humidity

• Fast surface distress (cracking,

rutting, shoving, etc.)

• Sound granite base and sub-

base

• Major repair every 10 years

rutting cracking

Standard road section in Singapore

(LTA website)

School of Civil and Environmental Engineering

Research Group of Living Stones @ NTU

Concrete Pavement in Singapore

Typical concrete pavement at traffic junction in Singapore (Source: LTA)

Concrete pavement lasts longer

However, …

School of Civil and Environmental Engineering

Research Group of Living Stones @ NTU

It Takes Longer to Build

Placement of steel

reinforcement is labour

intensive and time consuming

Concrete takes weeks

to gain strength

May cause traffic

jam and delay

Source: www.nairaland.com

Source: www.eiffeltradingcompany.com

School of Civil and Environmental Engineering

Research Group of Living Stones @ NTU

Precast Concrete Pavement for Quick Installation & Less Traffic Disturbance

Source: Chang et al.,2004

However, conventional precast concrete

pavement slab is heavy and bulky

Source: National Precast Concrete Association

From weeks for conventional concrete to hours

School of Civil and Environmental Engineering

Research Group of Living Stones @ NTU

Hot-Mixed

Asphalt

Cast-in-situ

Concrete

Precast Concrete Slab

Milling-off thickness ~100 mm ~250 mm ~250 mm

Service life expectancy 10 years 15-20 years 15-20 years

Open to traffic Overnight At least 14 days Overnight

Constructability Practiced

for years in

SG

Practiced for

years in SG

• One pilot project at Tanah

Merah Coast Rd.

• Complicated fabrication with

heavy reinforcement and joints

• Heavy crane (4-8 tone/slab)

Joint between precast slabs (Tanah Merah Coast Rd.)

dowel bar

School of Civil and Environmental Engineering

Research Group of Living Stones @ NTU

Bendable Concrete for Slim and Light Precast Paving Slab

Conventional concrete is

hard and brittle

Bendable concrete is still

hard but tough and deformable

• Elimination of reinforcement and pre-stressing

• Reduced thickness (i.e. slim and lightweight)

• Reduced joint

• Improved durability and extended service life

• Reduced environmental impact and (initial & life cycle)

cost

School of Civil and Environmental Engineering

Research Group of Living Stones @ NTU

Traffic direction

2.4m

3.4

m

10-12 slabs

Silicone sealing between slabs

Total BC volume: ~6-8 m3

Field Demonstration (On-going)

School of Civil and Environmental Engineering

Research Group of Living Stones @ NTUResearch Group of Living Stones @ NTU

LevellingCuring

CastingMixingBatching

Large Scale Processing and Slab

Manufacturing (On-going)

Surface treatment

School of Civil and Environmental Engineering

Research Group of Living Stones @ NTU

Lab

prototype

Large scale

processing

Compressive strength (MPa) 71 58

Flexural strength (MPa) 12.9 10.3

Ductility (%) 1.3 2.7

Comparable Material Performance

Obtained

Typical flexural stress-deflection curve

Lab prototype

Large scale

processing

Comparable fresh properties

(Lab vs large scale processing)

Comparable mechanical properties

(Lab vs large scale processing)

School of Civil and Environmental Engineering

Research Group of Living Stones @ NTU

Lifting and Handling of Full Size Precast

Bendable Concrete Slab

• 2.4 m x 3.6 m

• 60 mm in thickness

• No reinforcement

• Satisfied skid

resistance (BPN

~70-75)

• No cracking

observed

• Minimum

deformation during

lifting

School of Civil and Environmental Engineering

Research Group of Living Stones @ NTU

Full scale slabs manufacture (on-going)

Wheel tracker tests (structural performance evaluation)

Grouting tests

Full scale slab installation

Full scale wheel

tracker

Future Tasks

1/3 scale (0.8 m x 1.15 m) pavement sample with whole structure for

the wheel tracker test

School of Civil and Environmental Engineering

Research Group of Living Stones @ NTU

Acknowledgement

• JTC Corporation

• LTA

• NTU-JTC I3 Centre

• School of Civil and Environmental Engineering (CEE),

NTU

• TUM CREATE

• Mr. NG Kian Wee, Dr. Bernhard LECHNER, Dr. QIU

Jishen, Dr. Nen NGUYEN DINH, Mr. Ali Aryo

BAWONO, Mr. HE Shan

School of Civil and Environmental Engineering

Research Group of Living Stones @ NTU

Thank You for Attention!

Q & A