The Quebec’s contractors experience with SMA

Olivier Bouchard, ing. jr.

ACRGTQ – Secteur sciences et

techniques

Canada User Producer Group for

Asphalt

CUPGA – November 16th 2008

Saskatoon, Saskatchewan

What is ACRGTQ ?

Translation:

Quebec road builders and heavy

projects contractors association

A private sector association of

contractors who specializes in road

and civil engineering infrastructures

projects.

More than 550 members.

Overview

Introduction

Definition of SMA

Types of SMA used in

Quebec

Contractor’s challenges

Conclusion

Introduction

The Quebec Road Network– In Quebec, we have 185 000 km of road.

MTQ is responsible for

approximately 29 000 km of road,

including national and provincial

highways and regional and

collector roads. To built that, one thing is sure : YOU

NEED CONTRACTORS!!!

When they have a new technology

(like the SMA), the contractors have to

modify their working methods.

Definition of SMA

The high content of

crushed coarse

aggregates (>5 mm)

maximizes contact

between aggregates.

Good distribution of applied

loads

Excellent aggregate skeleton

Good rutting resistance

Good surface texture

Flexible at low temperatures

Suitable for thin courses

Quieter

No segregation

Longer service life

More expensive to produce than a

conventional HMA because :

– High asphalt content;– Use of asbestos fibres;– production of 0-2,5 mm granular

class.

Definition of SMA

Types of SMA used in Quebec

3 types of SMA

– SMA-10 (for highways and roads with high or heavy traffic)

– EGM-10 (palliative interventions)

– EG-10 (for highways, casual interventions, reduce noise)

Contractor’s challenges

The formulation of the SMA– Since 2008, Marshall’s method is out of

use. This method has been replaced by the LC mix design.

– LC mix design method is a combination of SUPERPAVE and LCPC method.

– The contractors have to modify their method of formulation.

– The new LC mix design method is gradually implanted in Quebec.

Contractor’s challenges

The progression is good for the contractors

98,7 96,4 94,5 94,689,4

50

251,3 3,6 5,5 5,410,6

50,0 50

75

50,0

53,158,558.167.6

75,476,676,7

46,941,541.9

32.4

24,623,423,3

0

20

40

60

80

100

1993 1995 1997 1999 2001 2003 2005 2007

Year

(%)

Marshall mixes

LC mixes (designed with GC)

Source :

MTQ

Contractor’s challenges

The formulation of the SMA

– New granulometric characteristics

Contractor’s challenges

Placement – MTQ has identified that pavement degradations

are mainly attributable to workmanship issues:• Thermal and granular segregations• Cyclic density differentials• Truck exchanges = open texture on the mat• Cold spots from asphalt spills• Transverse and longitudinal joints• Paver operation

– Solutions :• Material transfer vehicles (MTV) requirements• Infrared technology in roadwork

Contractor’s challenges

Placement– The infrared technology and the

MTV are used to check three points:

• If temperature of HMA is lower than the specification of the grade asphalt

• If temperature of HMA is higher than 100°C to eliminate the problem of bad compaction

• If we have longitudinal thermal segregation

Contractor’s challenges

Placement

– Problems

Placement

– Problems

Contractor’s challenges

Contractor’s challenges Placement

– Solutions : Material transfer vehicles

Contractor’s challenges

Placement

– Solution

Contractor’s challenges

Placement

– But the MTV is not the solution for ALL the problems…

Contractor’s challenges

Placement

– The longitudinal thermal segregation is a problem due to contractor's equipments. To eliminate that problem, a lot of work is made by the contractors and we hope that in few years, we have a durable solution for that problem.

Conclusion

In Quebec, we have a lot of road New technologies, like SMA, have many

repercussions on contractors. But when the new formulation is gradually implanted, contractors respect the demands with a lot of work.

For the placement of the HMA, new techniques are used by the contractors : infrared technology and MTV.

Good construction practices ensure good pavement performances.

In the future, MTQ and ACRGTQ have to work in team to ensure a good quality of asphalt road.

ContactOlivier Bouchard, ing., jr

Association des constructeurs de routes et grands travaux du Québec

435, Grande Allée Est

Québec (Québec) G1R 2J5

Phone : 418 529-2949

Toll free : 1 800 463-4672

Fax : 418 529-5139

www.acrgtq.qc.caobouchard@acrgtq.qc.ca