HMA in Quebec

Question 1

5 quebec realities

Answer 1

1. temperature from -30 to 30
2. high daily delta T during thaw period
3. overlay : more than 85% of paving projects
4. low temperature cracking is general
5. reflective cracking in overlay projects

Question 2

name 2 types of rutting

Answer 2

1. rutting by excessive creep in the HMA

2. rutting by deformation of granular layers

Question 3

what does low temperature cracking to the road?

Answer 3

cracks perpendicular to the road (road shrinks longitudinally and therefore road cracks perpendicularly)

Question 4

what is fatigue cracking

Answer 4

when there are multiple cracks in every direction

Question 5

what is the freeze-thaw action

Answer 5

frost heaving pulls the road up from the middle. water pumping feeding the ice lenses under the road.

Question 6

what happened in 1991?

Answer 6

studies of the french method by the laboratoire des chaussées

Question 7

what happened in 1993?

Answer 7

studies of the superpave method (first hot mix LC)

Question 8

what happened in 1997?

Answer 8

standardization of the laboratoire des chaussées method

Question 9

what happened in 2008?

Answer 9

standard 4202 used (4201 archived)

Question 10

what is the volumetric approach

Answer 10

fixed volume of asphalt for each mixture

Question 11

3 levels for basic concepts

Answer 11

level 1 : workability
level 2 : rutting testing
level 3 : complex modulus, fatigue, thermal properties (in development)

Question 12

describe level 1

Answer 12

gyratory compactor.

600 kPa pressure
150 mm diameter
30 gyrations/minute
1,25° inclination

Question 13

describe level 2

Answer 13

rutting test.

• • not more than 10 mm rut depth
• • 1k, 3k and 30k cycles
• • 5 kN load applied
• • 600 kPa tire pressure
• • 50, 58 and 60 °C

Question 14

what is ESAL

Answer 14

equivalent single axle load

Question 15

what is aadt

Answer 15

average annual daily trafic

Question 16

3 necessary info for the LC mix design method

Answer 16

1. traffic info (type, esal, aadt, other)
2. environmental constraints
3. construction issues – pavement function

Question 17

4 things HMA should satisfy according to the LC mix design method

Answer 17

1. minimum asphalt cement content (durability, ravelling, stripping, thermal cracking, resistance to fatigue and rutting)
2. stability under traffic loadings (rutting and creep)
3. minimum voids (to avoid binder bleeding)
4. maniability and good compaction ability

Question 18

binder selection is based on

Answer 18

Range of T°

level of traffic

Question 19

4 components of the global approach of the LC method

Answer 19

1. binder selection
2. optimisation of the components
3. verify rutting resistance
4. verify moisture damage resistance

Question 20

quebec climate zones : define

Answer 20

3 climate zones

zone 1 : montréal métropolitain
zone 2 : côtes + sud du québec
zone 3 : nord du québec

Question 21

what is coarse graded

Answer 21

enrobés grenus : EG

Question 22

what is dense graded

Answer 22

enrobés semi-grenis : ESG

Question 23

what is correction course

Answer 23

enrobé de correction : EC

Question 24

what is stone matrix

Answer 24

enrobés de matrice à pierre : SMA

Question 25

what is base course

Answer 25

enrobé pour couche de base : GB

Question 26

what is SGC

Answer 26

superpave gyratory compactor

Question 27

ESG-10 is

Answer 27

the type of surface course most used, it performs well on all types of roads

Question 28

EG-10 is

Answer 28

used on highways, near urban zones (diminishes road-tire noise)

Question 29

EGA-10 is

Answer 29

EG-10 with 1,3% asbestos fibers and a stronger grade of asphalt

Question 30

what is EGM-10 for?

Answer 30

for thin overlays (M= mince)

Question 31

GB-20 v ESG-14

Answer 31

GB-20 remains the best chioce for base course.

ESG-14 is a possibility in cold weather but its bearing and rutting resistance is less

Question 32

ESG-14

Answer 32

performs well as a single course but it is difficult to formulate

Question 33

layer thicknesses

Answer 33

top layer : 30 to 60 mm
middle layer : 100 to 150 mm
base layer : 75 to 100 mm

granular or stabilized foundation

Question 34

what is the maximum percentage of recycled pavement allowed in new pavement in quebec since 2008?

Answer 34

20%

Question 35

can asphalt shingles and warm mix asphalt be used in the MTQ road network?

Answer 35

yes but with a performance follow-up