The Material Transfer Vehicle (MTV) and pavement smoothness play a prominent role in the latest version of the Caltrans pavement specifications. Hear from an expert manufacturer representative on best practices to achieve the optimum pavement performance.

1. MTV and Pavement Smoothness
Jeff Ensell

2. Benefits of Smooth Pavements
1. Smoother roads are important to the road users (taxpayer)
2. Smoother roads last longer
3. Smoother roads stay smoother longer
4. Smoother roads save money
5. Smoother roads are safer
6. Smoother roads improve mobility

3. What is a MTV

4. What do they do?
An MTV transfers material from a truck and puts it directly to a laydown machine.

5. A Mobile Silo and Mixer
• The MTV is a part of the
asphalt mixing plant on the
job site.
• It receives the material
from the delivery truck and
then remixes and blends
this to the original plant
specification.

6. Why Use a MTV
• Eliminate Physical Segregation
• Re-Mix HMA
• Provide Site Storage
• Stop Truck Delays
• Eliminate Paver Stops/Start
• Smoother Roads Last Longer
• Require Less Maintenance

7. Stopping Cost Money!
35’ / min * 60 min= 2100’ / HR
150’ stop for 2.5 min
2100’ stopped 14 times
35’ / min * 2.5 min= 87.5’
87.50 * 14= 1225’
2100 – 1225= 875’ / HR
Production

8. Thermal Segregation
• 20°F (11°C) Differential = 1%
to 2% Air Voids
• Over 7% Air Voids Reduces Life
• Each 1% Over 7% Reduces Life
by 10%
Source: WSDOT

9. Thermal Segregation
Temperature Differentials greater
than 25°F results in 2% increase
in air voids and result in failing
density profiles approximately 90
percent of the time.
Source: WSDOT

10. Why Use a MTV

11. No matter how simple the truck

12. No matter how complex the truck
Insulated Truck owned by a large Dutch Contractor

13. Both Loose Heat
Thermal Segregation is one of the reasons that
asphalt pavement prematurely fails.
Aggregate Size Segregation is caused by the
same movement of the delivery vehicle as
Thermal.

14. I Want My MTV

15. Why Use a MTV

16. Bring your machine up to the truck and then raise the bed when
possible.
When unloading a truck, discharge the material as a mass instead
of dribbling the material into a paver.
RP195
Truck Exchanges
What about Time ? Time =Production

17. Pulling Force
( Force P )
Head Of Material
( Force M )
Shear Force Between
The Material and the
Screed. ( Force F )
Reaction Of Material
Under The Screed
( Force R )
Weight Of The Screed
( Force W )
FR
M
P W
Forces acting on the screed

18. Day 1 Infrared Data – 1000 ft. by 12 ft. lane
Cold spots (blue) at 130 ft. intervals (truck ends)

19. 6.4%
Voids
14.8%
Voids
Severe Thermal Segregation
Mean mix temp has dropped ~ 20 F
Localized temperature differential is key

20. Paver stop ~ 35 minutes ~ 20 ft of
mat not rolled during this time.
Area becomes low density
regardless of temp at time
of placement Bump felt at transition
Rolling
delay
Surface temp ~ 117
F before rolling
15.0 % Voids
Paver Stops

21. • Remove trucks from paver
• Trucks are not bumping
paver causing it to change
speed and put marks in mat
Non-Contact Paving

22. Constant Speed Paving
• Changing speeds while
paving changes the forces
on the screed
• Shuttle Buggy allows paver
to keep moving
• Stores mix on site
• Paver doesn’t slow down to
accept truck

23. Dump Person
Be sure the truck driver and the paver operator know
when you are between them.
Be aware if the back up alarms on the trucks are not
working.
Communicate well with the truck driver when it comes
time to pull out in live traffic. Make sure it is safe.
Keep unwanted material off the road in front of the
paver
Looks out for power lines and limbs

24. Infrared Data – with MTV

25. Proper material transfer

26. Material Flow & Loading Material
RP195
Remember, make sure that the C2 has at least 1/3rd to
2/3rd capacity at all times.

27. Proper material transfer
RP195
If the insert is always out or low, you will
see the same problem with Material
Segregation.

28. Proper material transfer
Think of how sand would come out of a
glass at different heights.

29. What about the Insert?
If the insert is always out or low you will see
problems with Material Segregation.
Stop the paver before the material drops
below flow gate.
Keep the conveyor deck covered with a
minimum of 12 to 24 inches of material.

30. What Insert??
I have a transfer machine….. What’s
the problem??

31. The Other Reasons…..

32. Moba Pave IR

33. Moba Pave IR
If you need to know why you should use a MTV this will show you the way!

34. REPORT

35. REPORT

36. CONCLUSION:
• Initial Ride Quality can be improved by
minimizing stops and including a material
transfer device
• When used properly, Shuttle Buggy improved
the ride quality and eliminated thermal &
physical segregation
• Results show no significant thermal segregation
when a material transfer device was used
Source: Texas Transportation Institute

37. Why? Because they make you Happy