Precast Bendable Concrete Paving Slab for Speedy Road Construction

Transcription

1 I 3 C Symposium on Industrial Infrastructure Research Precast Bendable Concrete Paving Slab for Speedy Road Construction presented by Yang En-Hua, PhD, LEED AP Assistant Professor & Assistant Chair (Academic) Nanyang Technological University (NTU) 23 November 2017 TSB Public Lecture Series on Sustainable Urban Living 8 April 2016, Singapore

2 Hot-Mixed Asphalt (HMA) Road Surface in Singapore rutting cracking 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 subbase Major repair every 10 years Standard road section in Singapore (LTA website)

3 Concrete Pavement in Singapore Typical concrete pavement at traffic junction in Singapore (Source: LTA) Concrete pavement lasts longer However,

4 It Takes Longer to Build May cause traffic jam and delay Concrete takes weeks to gain strength Source: Placement of steel reinforcement is labour intensive and time consuming Source:

5 Precast Concrete Pavement for Quick Installation & Less Traffic Disturbance From weeks for conventional concrete to hours Source: Chang et al.,2004 Source: National Precast Concrete Association However, conventional precast concrete pavement slab is heavy and bulky

6 Hot-Mixed Asphalt Cast-in-situ Concrete Milling-off thickness ~100 mm ~250 mm ~250 mm Service life expectancy 10 years years years Open to traffic Overnight At least 14 days Overnight Constructability Practiced for years in SG Practiced for years in SG Precast Concrete Slab One pilot project at Tanah Merah Coast Rd. Complicated fabrication with heavy reinforcement and joints Heavy crane (4-8 tone/slab) dowel bar Joint between precast slabs (Tanah Merah Coast Rd.)

7 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

8 3.4m Field Demonstration (On-going) slabs Silicone sealing between slabs 2.4m Traffic direction Total BC volume: ~6-8 m 3

9 Large Scale Processing and Slab Manufacturing (On-going) Batching Mixing Casting Surface treatment Curing Levelling

10 Comparable Material Performance Obtained Typical flexural stress-deflection curve Lab prototype Large scale processing Comparable fresh properties (Lab vs large scale processing) Lab prototype Compressive strength (MPa) Large scale processing Comparable mechanical properties (Lab vs large scale processing) Flexural strength (MPa) Ductility (%)

11 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

12 Future Tasks Full scale slabs manufacture (on-going) Wheel tracker tests (structural performance evaluation) Grouting tests Full scale slab installation Full scale wheel tracker 1/3 scale (0.8 m x 1.15 m) pavement sample with whole structure for the wheel tracker test

13 JTC Corporation LTA NTU-JTC I 3 Centre Acknowledgement (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

14 Thank You for Attention! Q & A