Locations
3/6/2018
Laydown Best Practices Jeff Ensell C.W.Matthews Contraction Co. Inc.
Locations • Our main office is in Marietta, off of Old Hwy 41 near Kennesaw Mountain. • We have 26 asphalt plants throughout North Georgia.
Operating Divisions • Eight Operating Divisions • • • • • • • •
Asphalt Construction Asphalt Plants Quality Control and Terminals Roadway Construction Bridge Construction Concrete Construction Major Projects Equipment
1
3/6/2018
Build the Best Crew Everyone involved in the paving process contributes to the overall smoothness of the pavement, including: a. Paver operators b. Raker’s / luter’s c. Truck drivers d. Roller operators.
Good Leadership = Longevity “A Leader ONLY gets things done through OTHERS. The leader must have the ability to inspire, motivate, guide, direct, and most importantly LISTEN. It’s only through communication (VERBALLY and ACTIONS) that a leader is able to cause others to see their vision and implement it.”
How can we do our best work We should promote teamwork. Cross training every position within the crew is key. When one is out they have another who can take the place and perform. Not only can they fill the position but they also understand the importance of that person’s position on the team. Somebody that’s walked around in another’s boots knows what they feel like. Should we have Trainers?? Will they stay busy enough for me to justify the position? Every company has rework. One job of remove and replace, I think will be justification enough. When you start a high profile job, so should the trainer.
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3/6/2018
How can we do our best work Why should we train? 1. Increase productivity 2. Reduce employee turnover 3. Decrease need for supervision 4. Help employees meet new responsibilities 5. Increased job satisfaction, morale and motivation among employees
Investing in your employees will let them know you are interested in developing their skills. As a result they tend to stay longer and contribute more to your business.
How can we do our best work So why do we need to train? Because it works. It promotes quality. It inspires your people to be a part of something great. Commit to make them the best and they will give you their best. Keep them Trained, keep the Inspired and keep the wanting to work for you tomorrow. When you keep them coming back to work and doing their best for your company, this is the ultimate Return On Investment.
We all want the same thing. What are the first questions the boss should ask every day? Was it a safe work day! How many QUALITY TONS did you get put down When your people are just pushed for production they can loose their care for Quality.
It’s all about the QUALITY TONS! Can we have both?
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3/6/2018
Leadership = More quality Tons True leaders don’t create followers, They create MORE LEADERS What are the characteristics of a leader: •
1) Passionate
•
2) Coach/ Teacher/ Mentor -
•
3) Patience
•
4) Listener
•
5) Has high levels of Confidence and optimism
•
6) Knows their strengths and weaknesses
•
7) Acknowledge the need for change
•
8) Initiative
• •
9) Forms one-one relationships (Character, Respect) 10) Communication
Milled Surface
How old ??
4
3/6/2018
30 fpm vs. 120 fpm 2.3 miles in a day vs. 9.1 miles in a day
Tack!
It’s All Balance To build high quality, smooth riding roads, the paving speed MUST be at a constant rate. Consistency win’s every time!
Quality Paving Techniques:
1)
Uniformed “Head of Material”
2)
Proper Angle of Attack
3)
Constant Speed of Paver
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3/6/2018
Evolution of Paving The early pavers used screw conveyers to distribute the mix in front of a screed that tamped the mix. This was suitable for coarse-graded mixes, however on dense-graded mixes that were common on city streets the machine experienced problems including surface imperfections.
Didn’t take them long to figure out that not all mixes reacted the same..
Understanding the Asphalt Paver. The two components are: The Tractor:
The tractor pushes trucks and tows the screed.
The Screed:
The screed slopes and lays the desired depth needed per job spec.
Understanding the Asphalt Paver.
The main purpose of the screed is to: 1.
Spread the paving material
2.
Provide initial compaction
3.
Contour the road surface
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3/6/2018
Rubber Tire The tractor’s self leveling action is the wheel base of the paver. From the center line of the gearbox to the centerline of the shaft between the bogies is the internal ski with the paver.
Advantages, Maneuverability Speed to other locations Contact with the ground due to the front bogies.
Track-paver The internal ski here, is the gear box center line to the idler wheel center line. Great for wide width paving Great on soft base High traction
Screed Pre Strike-off Check the Pre Strike Off before you start. Look for adjustment and the overall condition of the plate.
½”
The bottom of the strike off is set ½” above the screed bottom and is adjustable from the top of the screed.(12.5mm)
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3/6/2018
Screed Angle of attack In order for a screed to produce a mat that has consistent density and texture, the pressure exerted by the rear of the screed plate must be equal along the entire plate.
A normal angle of attack is set on the rear extension to 3/16 (4.5mm). As the angle of attack is changed on the main screed then it will effect the vertical on the rear extension. Adjusting the angle of attack on some screeds is done on the screed plate itself and not through a single adjustment.
Screed Angle of attack On a screed with front extensions, the angle of attack on the extensions is adjustable.
As the angle of attack is changed on the main screed you have to watch the vertical adjustment of the extension. A level should be flat along the main, and the tail of the extension should touch the level. You should then see a 3/16 (4.5mm) air-gap at the front of the extension.
String lining the Screed
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3/6/2018
Check for slope in your extension. When you finish at one end of the job and start at another spot, is it possible that somebody could have bumped switches in the move?
How many would have caught this quick?
Checking the Crown Think of how much material you could overrun
Correction Time of the Screed Direction of Paving
Screed Path
87%
63%
96%
98%
99%
Step Amplitude = 100%
0 1L L = Leveling Arm Length
2L
3L
4L
Tow Point Path
5L
6L
This theory only applies to running the screed manually. In automatic, you don’t see these effects?
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3/6/2018
Forces acting on the screed Weight Of The Screed ( Force W ) Pulling Force ( Force P )
P
W M Head Of Material ( Force M )
R
Reaction Of Material Under The Screed ( Force R )
F Shear Force Between The Material and the Screed. ( Force F )
Line of Pull Although the tractor is averaging the ride, what’s important is to keep a proper Line of Pull between the surface and the screed.
1992 Blaw-Knox Manual
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3/6/2018
Line of Pull With a high tow-point and a thin lift you would have a line of pull that is always pulling upward. This upward pull would have an effect that would want to put pressure on the screeds’ nose. The tow-point reaction time will be fast to increase the mat thickness and slow to reduce mat thickness
Line of Pull Place the tow-point 1 in higher then the loose mat thickness you are laying. This will give you a slight angle of attack in the screed, and a more even response time in both directions when moving the tow-point.
Line of Pull
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3/6/2018
Feed System Components Flow Gates & Slat Conveyers
Hopper
Feeder Sensor & Controller
Augers The Hopper is to receive the mix. Slate conveyors carry it through the paver tunnel. Flow gates to strike off the mix. Augers to distribute the mix in front of the screed. Sensors to control the material level at the outboard edge of the screed.
Feed System Components Flow Gates & Slat Conveyers
Feeder Sensor & Controller
Augers
Flow gates to strike off the mix. Augers to distribute the mix in front of the screed.
Flow Gates Remember flow gates are designed to Meter the amount of material that is delivered to the Auger Chamber. With this width, what should we do with the Flow-Gates? So in this width, we will just move the gates down a little, or a lot?
What else could we do to help manage the Material in this application?
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3/6/2018
Irregular head of material Gradation changes in the mix design will effect how a screed reacts.
When you have an irregular head of Material, you can usually see the same imperfections in the Mat.
Feeder Placement This is one of the major problems in the field hands down!
When should I change my Feeder position? What benefit will I see from a different position?
Managing the Feed System The correct position as illustrated here, will cure many problems with your paving operation. Material that is not manageable will make a mat that is unmanageable.
This is easy don’t make it harder than it has to be.
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3/6/2018
TOWPOINT
Feed Speed EXTENSION
FLOW GATE
CONVEYOR
VERTICAL
AUGERS OVERRIDE
STOP
CROWN
SET UP
STOP
STD
RUN
EMERGENCY STOP
FEED SPEED EMERGENCY SHUTOFF
STOP
TUNNEL EXTENSION
AUGERS LEFT
BERM
RUN
DECREASE
SLOPE
FEED SYSTEM
REV
GENERATOR
INCREASE
FEED MODE
RUN
RIGHT
SCREED CONTROL
HORN
SET UP
RUN
Managing the Feed System
Auger Height Auger height controls the head of material and is determined by mat thickness. Add 2 inches or 50mm to the loose thickness you are laying, or more for larger aggregates.
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3/6/2018
Auger Adjustments The head of material is the asphalt that is carried in front of the screed There is no need to carry anymore material in front of the screed than is required to feed the entire length of the screed.
Augers break. Augers get worn out. Augers can be changed.
Adjusting the head of material. You should have an even amount of material across the auger chamber, and your augers should be running 100 % of the time.
Adjustments.
1 10
Looking across the tunnel will tell you a lot about the head of material. You could resolve this problem by adjusting the flow gates or slow down and adjust the pile height.
9
2 3 4
8 7 5 6
Pile Height
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3/6/2018
Proper Pile Height What we see is the correct head of material and an even flow of material across the auger chamber. Augers need to run all the time… not one faster than the other….Equal amount flowing in and equal amount flowing out..
If it needs to be shoveled to make it to the end, then do it!
Augers Extension Auger extensions should always be used when wider paving is done. Some material designs may require additional auger extensions that would not be required when working with traditional material designs.
How will material stay contained, uniform and continuously move with out them?
The Art of the Start..
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3/6/2018
Think of how much material…
Material Management Summary Key Points in Prevention of Segregation:
• Keep Material Contained • Prevent Excessive Rolling of Materials • Move Material in a Smooth Uniform Uninterrupted Manner.
What the Customer’s Demand Long Life Pavement Proper Sub-grade Substantial Structural life Pavement Smoothness No Material Segregation No Temperature Segregation Uniformity of Density Speed of Construction Minimizing Traffic Delays Low Price
That’s It…… Easy Enough!
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3/6/2018
Constructing Smooth Pavement Whether new construction or rehabilitation, a. Good planning b. Communication c. Proper mix production d. Delivery e. Correct placement techniques These Key Steps are necessary to ensure a smooth HMA pavement.
Asphalt Plant Production We need to know how much asphalt can be produced for this job. The plant may be making asphalt for jobs other than just our job. The tonnage per hour that is available for your job is needed to calculate paver speed.
Number of Trucks needed
How many do I need to get through the day?
Am I going to have 20 deep and then wait an hour? Will I get one at a time? Will the drivers turn the corner and wait for their buddy or buddies? I need to be prepared to adjust my operation to insure a good mat quality under many different conditions…… Communication
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3/6/2018
Job Layout
You may lay this job out and it be just how you like it until the crew see’s it. If there is a better way to make the job easier, then listen.
In the end you may have to make fewer passes to do the same job.
Job Layout Great Example!!
Preparing for the job The paver size needs to be matched to production rates and job conditions. Now, not everybody has a fleet of pavers to choose from and you may just get what you get. If you have a job that is paving 10’ wide then use a 8’ paver when possible. (3m or 2.43m) If you open an 8 footer up to10, your operation will more than likely benefit. No 10’ paver likes to run closed up and no crew likes to run one that way..
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Paving width setup What typically happens is that you create pressure that builds on the extension. As we said earlier, if you have added pressure on the screed, you are not balanced.
Paving width setup As you can see here, it does happen. If you were to pave at this width you would see problems with the surface.
Existing Grade Conditions What the existing surface is like can determine many things that should be changed to balance production and maintain quality. Am I on a stone base that is loose or wet? I will need to explain to my drivers that you holding the brakes will not work. (this never get’s through) but yelling and blowing the horn always will…. For those with track machines, this is not a big issue but twisting the machine around on the material is an issue and should be raked over and smooth.
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3/6/2018
It’s ok, it will cover Cover it, is not the answer here. Not all jobs are perfect but the customer needs to know what happens when jobs are rushed.
Existing Grade Conditions
Please don’t core here….
How hard can it be?? Our construction steps. Balance our production. Layout the job with a plan. Setup the machine to pave Pull off the joint Transition material, again balance your production. Make a joint. Match a joint
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3/6/2018
What do we need to pull off?
If we just set down and pull off without any prep then we will go down. Setting down and getting the following in order will give us a successful takeoff. Allow for roll down. That means use starter plates…
Setup the paver for the application. This means width, tow point position, proper electronics setup.. Start with the correct head of material. This means what you start with should be what you use for the entire pull… Take your time before adjusting.
What do we need to pull off?
If we just set down and pull off without any prep then we will go down. Setting down and getting the following in order will give us a successful takeoff.
Execute proper material control. This means even after you start you need to keep an eye on your feed.. Check the joint with a straight edge. This means ensuring the joint is correct in both directions..
Mat Thickness Chart To achieve the proper Mat thickness, you should always allow for roll down. Roll down is the differential between the non–compacted and compacted material.
To Achieve Final Mat Thickness: 1” or 25.4 mm 2” or 50.8 mm 3” or 76.2 mm 4” or 101.6 mm
Requires an Initial Thickness Of: 1.26” or 32.0 mm 2.53” or 64.3 mm 3.79” or 96.3 mm 5.05” or 128.3 mm
Mat Thickness Chart
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Set the tow-point
Wash Down
Where should this Tow-Point be set? There are times that this will depend on the thickness of the mat, but a good rule to follow is 1 inch above the loose mat thickness
Pulling Off Allow for your roll down. Set the screed down and pull the slack out of the tow arm. Why is there a need to pull the paver forward?
Null out the screed, using both screws together.
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3/6/2018
Add angle of attack
Pulling Off Load your auger chamber with material. Here is a great example of containing your material as you take off. Make sure that you don’t fill the auger chamber until it builds a mountain of material.
Zero out
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Zero out
Make sure you have zero
Go to automatic
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Auto on
Offset if needed after you check..
Offset if needed after you check..
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3/6/2018
Don’t set yourself up to fail.
¾” Start plate
Start plates should be as long as the screed is deep.
Use a straight-edge Most foreman have a straight-edge on a service truck, but for the most part they seldom get used. This is a very important tool in the joint construction process. Using a straight-edge will help increase the quality of the joint’s as well as crown adjusting, sloped extensions and vertical.
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3/6/2018
Use a straight-edge
Joint Prep. Good example of taking off on the header, except too much material was brushed up on the mat. The result is segregation and will change the thickness of the mat. The solution is to remove the larger rock.
Joint Prep.
Very little has to be done to this joint after pulling off because the setups were done properly. If you have a joint that is too thick, you have problems. The spreading or broadcasting of material is what will more than likely cause a failed joint.
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3/6/2018
Checking depth and yield When correct depth is the most important thing, then what happens here? This spillage will gain ¾ of an inch in depth at this area. (19mm)
If you only have X to put down then pay attention to what is going on around you
Trucking Issues.. I want my MTV !!
Stopping Cost Money!
35’ / min * 60 min= 2100’ / HR 150’ stop for 2.5 min Down to 875’ / HR
Production
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3/6/2018
Day 1 Infrared Data – 1000 ft. by 12 ft. lane Cold spots (blue) at 130 ft. intervals (truck ends)
Dump Person
Be sure the truck driver and the paver operator know when you are between them. Communicate well with the truck driver when it comes time to pull out in live traffic. Make sure it is safe. Takes tickets from drivers Keep unwanted material off the road in front of the paver Looks out for power lines and limbs
Truck Exchanges 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.
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3/6/2018
Truck transition’s Dumping material in front of the paver as the truck pulls away can cause the paver to ride over the pile of material with adverse effects on mat quality.
When should I empty the Hopper? When you limit the amount of times you empty the hopper, you will have a much better Mat quality.
Stop the paver before the material drops below flow gate. Set and keep the conveyor deck covered with a minimum of 6 to 10 inches of material. (152-254mm)
When should I empty the Hopper? When working with segregating materials, the hopper wings should only be cycled with the hopper relatively full. This bunches the segregated materials that collect in the hopper wings instead of flipping them into an empty center area.
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3/6/2018
Stopping and Starting It is recommended that you stop the paver as quickly as possible and accelerate as quickly as without being erratic.
This helps not only to minimize mat deviations, but also to maintain a constant, uniform head of material.
Segregation
Thermal Segregation is one of the reasons that asphalt pavement prematurely fails. Aggregate Size Segregation is caused by the same delivery vehicle as Thermal.
Why Use a MTV
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Infrared Data – with MTV
Proper material transfer If the insert is always out or low, you will see the same problem with Material Segregation. Might as well use a truck….
RP195
What about the Insert? 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. If the insert is always out or low you will see problems with Material Segregation.
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Why Use a MTV??
The Prosecution rests !!
Joint Prep. This is a good example of a header. It is cut back far enough where the paver laid a good mat, they will have a good joint for the next day.
Joint Matching The first rule of joint matching might be to avoid creating situations which promote failure. If the crew cannot accurately match the joint during placement , then joint is doomed to failure.
JOINT FAILURE AHEAD
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3/6/2018
Joint Matching
If the roll down factor is correct, you may not even touch the material. If the correct steps are taken you should not have to touch the joint.
Joint Matching
Joint Matching Can we joint match with a ski?? Absolutely…
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3/6/2018
Joint Matching Align the screed with the end gate overlapping no more than one inch on the existing joint.
Make sure your joint matcher is in the correct position. Remember the closer you are to the augers, the more reactive your screed is.
Joint Matching As you lower the screed onto the shims needed, check the end gate so that it is free to float up and down on the ground.
RP195
Joint Matching
Free to float up and down on the ground.
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Joint Prep. Proper joint solutions involve the following: Eliminate the joint altogether. Echelon paving. Proper mat overlap.
Joint Prep.
Segregation Even though material has been successfully processed through the cold feed bin, the plant, the surge or storage bin, then uniformly loaded on the truck, segregation can still occur in the paver.
Improper operation of a paver can cause segregation in varying degrees.
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End of load
Mat Quality and Texture This mat (under extension) is too tight and shiny: The angle of attack jack should be turned approximately one revolution counter clockwise to push the bull nose down to decrease mix feeding under the screed extension, thus transferring more weight to the main screed.
Mat Quality and Texture By adjusting the extensions to tighten the Mat, you will notice changes in the Texture. Clockwise tightens the Mat. Counter Clockwise loosens the Mat.
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3/6/2018
Send in the Mill What Happened to the Margin?
A great start for a strong joint
This picture tells a story..
90% of the time things are good It’s that 10 % that gets you every time…
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3/6/2018
What Happened When I ? Put my controller into Automatic and the Tow-point shot to the bottom. Started into a super and the mat on the left side got very loose and the tow-point shot to the bottom. Set my sensor up on our string and the sensor will not lock on. Came to a stop and a crew member leaned on the string and the tow-point moved. Came to a stop and the feed system over filled. Came to a stop by turning the speed pot and all the sensors were still working. Was running slope and the material was getting too thin on the slope side. Was averaging and getting a variable depth. Plugged in my control box and the display was blank. Put my foot under the sensor and the tow-point moved up. Decided that I needed to adjust the system and now the system will not work.
Pave by the numbers. 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. 16. 17. 18. 19. 20.
Heat the screed. Set the tow points. Set the paving width. Set the crown height. Set extension height. Set extension slope. Set screed, remove slack. Null the screed. Position end gates. Set auger height. Fill the auger chamber. Adjust the feeder controls. Set accessory functions. Pull off with starter blocks. Double check settings. Adjust the grade system. Null or survey controls. Go to automatic. Start slow and consistent. Adjust depth as needed.
Thank you Outstanding leaders go out of their way to boost the self-esteem of their personnel. If people believe in themselves, it's amazing what they can accomplish.
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3/6/2018
Thank You Session Evaluations/PDH’s
See you again at:
• Professional Development Hours logged in session feedback.
• World of Asphalt 2019
• Complete session feedback in mobile app.
• February 12-14, 2019 • Indianapolis, IN
• CONEXPO – CON/AGG 2020 • March 10-14, 2020 • Las Vegas, NV • 140+ education sessions
#WorldofAsphalt
41
Laydown Best Practices Jeff Ensell C.W.Matthews Contraction Co. Inc.
Locations • Our main office is in Marietta, off of Old Hwy 41 near Kennesaw Mountain. • We have 26 asphalt plants throughout North Georgia.
Operating Divisions • Eight Operating Divisions • • • • • • • •
Asphalt Construction Asphalt Plants Quality Control and Terminals Roadway Construction Bridge Construction Concrete Construction Major Projects Equipment
1
3/6/2018
Build the Best Crew Everyone involved in the paving process contributes to the overall smoothness of the pavement, including: a. Paver operators b. Raker’s / luter’s c. Truck drivers d. Roller operators.
Good Leadership = Longevity “A Leader ONLY gets things done through OTHERS. The leader must have the ability to inspire, motivate, guide, direct, and most importantly LISTEN. It’s only through communication (VERBALLY and ACTIONS) that a leader is able to cause others to see their vision and implement it.”
How can we do our best work We should promote teamwork. Cross training every position within the crew is key. When one is out they have another who can take the place and perform. Not only can they fill the position but they also understand the importance of that person’s position on the team. Somebody that’s walked around in another’s boots knows what they feel like. Should we have Trainers?? Will they stay busy enough for me to justify the position? Every company has rework. One job of remove and replace, I think will be justification enough. When you start a high profile job, so should the trainer.
2
3/6/2018
How can we do our best work Why should we train? 1. Increase productivity 2. Reduce employee turnover 3. Decrease need for supervision 4. Help employees meet new responsibilities 5. Increased job satisfaction, morale and motivation among employees
Investing in your employees will let them know you are interested in developing their skills. As a result they tend to stay longer and contribute more to your business.
How can we do our best work So why do we need to train? Because it works. It promotes quality. It inspires your people to be a part of something great. Commit to make them the best and they will give you their best. Keep them Trained, keep the Inspired and keep the wanting to work for you tomorrow. When you keep them coming back to work and doing their best for your company, this is the ultimate Return On Investment.
We all want the same thing. What are the first questions the boss should ask every day? Was it a safe work day! How many QUALITY TONS did you get put down When your people are just pushed for production they can loose their care for Quality.
It’s all about the QUALITY TONS! Can we have both?
3
3/6/2018
Leadership = More quality Tons True leaders don’t create followers, They create MORE LEADERS What are the characteristics of a leader: •
1) Passionate
•
2) Coach/ Teacher/ Mentor -
•
3) Patience
•
4) Listener
•
5) Has high levels of Confidence and optimism
•
6) Knows their strengths and weaknesses
•
7) Acknowledge the need for change
•
8) Initiative
• •
9) Forms one-one relationships (Character, Respect) 10) Communication
Milled Surface
How old ??
4
3/6/2018
30 fpm vs. 120 fpm 2.3 miles in a day vs. 9.1 miles in a day
Tack!
It’s All Balance To build high quality, smooth riding roads, the paving speed MUST be at a constant rate. Consistency win’s every time!
Quality Paving Techniques:
1)
Uniformed “Head of Material”
2)
Proper Angle of Attack
3)
Constant Speed of Paver
5
3/6/2018
Evolution of Paving The early pavers used screw conveyers to distribute the mix in front of a screed that tamped the mix. This was suitable for coarse-graded mixes, however on dense-graded mixes that were common on city streets the machine experienced problems including surface imperfections.
Didn’t take them long to figure out that not all mixes reacted the same..
Understanding the Asphalt Paver. The two components are: The Tractor:
The tractor pushes trucks and tows the screed.
The Screed:
The screed slopes and lays the desired depth needed per job spec.
Understanding the Asphalt Paver.
The main purpose of the screed is to: 1.
Spread the paving material
2.
Provide initial compaction
3.
Contour the road surface
6
3/6/2018
Rubber Tire The tractor’s self leveling action is the wheel base of the paver. From the center line of the gearbox to the centerline of the shaft between the bogies is the internal ski with the paver.
Advantages, Maneuverability Speed to other locations Contact with the ground due to the front bogies.
Track-paver The internal ski here, is the gear box center line to the idler wheel center line. Great for wide width paving Great on soft base High traction
Screed Pre Strike-off Check the Pre Strike Off before you start. Look for adjustment and the overall condition of the plate.
½”
The bottom of the strike off is set ½” above the screed bottom and is adjustable from the top of the screed.(12.5mm)
7
3/6/2018
Screed Angle of attack In order for a screed to produce a mat that has consistent density and texture, the pressure exerted by the rear of the screed plate must be equal along the entire plate.
A normal angle of attack is set on the rear extension to 3/16 (4.5mm). As the angle of attack is changed on the main screed then it will effect the vertical on the rear extension. Adjusting the angle of attack on some screeds is done on the screed plate itself and not through a single adjustment.
Screed Angle of attack On a screed with front extensions, the angle of attack on the extensions is adjustable.
As the angle of attack is changed on the main screed you have to watch the vertical adjustment of the extension. A level should be flat along the main, and the tail of the extension should touch the level. You should then see a 3/16 (4.5mm) air-gap at the front of the extension.
String lining the Screed
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3/6/2018
Check for slope in your extension. When you finish at one end of the job and start at another spot, is it possible that somebody could have bumped switches in the move?
How many would have caught this quick?
Checking the Crown Think of how much material you could overrun
Correction Time of the Screed Direction of Paving
Screed Path
87%
63%
96%
98%
99%
Step Amplitude = 100%
0 1L L = Leveling Arm Length
2L
3L
4L
Tow Point Path
5L
6L
This theory only applies to running the screed manually. In automatic, you don’t see these effects?
9
3/6/2018
Forces acting on the screed Weight Of The Screed ( Force W ) Pulling Force ( Force P )
P
W M Head Of Material ( Force M )
R
Reaction Of Material Under The Screed ( Force R )
F Shear Force Between The Material and the Screed. ( Force F )
Line of Pull Although the tractor is averaging the ride, what’s important is to keep a proper Line of Pull between the surface and the screed.
1992 Blaw-Knox Manual
10
3/6/2018
Line of Pull With a high tow-point and a thin lift you would have a line of pull that is always pulling upward. This upward pull would have an effect that would want to put pressure on the screeds’ nose. The tow-point reaction time will be fast to increase the mat thickness and slow to reduce mat thickness
Line of Pull Place the tow-point 1 in higher then the loose mat thickness you are laying. This will give you a slight angle of attack in the screed, and a more even response time in both directions when moving the tow-point.
Line of Pull
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Feed System Components Flow Gates & Slat Conveyers
Hopper
Feeder Sensor & Controller
Augers The Hopper is to receive the mix. Slate conveyors carry it through the paver tunnel. Flow gates to strike off the mix. Augers to distribute the mix in front of the screed. Sensors to control the material level at the outboard edge of the screed.
Feed System Components Flow Gates & Slat Conveyers
Feeder Sensor & Controller
Augers
Flow gates to strike off the mix. Augers to distribute the mix in front of the screed.
Flow Gates Remember flow gates are designed to Meter the amount of material that is delivered to the Auger Chamber. With this width, what should we do with the Flow-Gates? So in this width, we will just move the gates down a little, or a lot?
What else could we do to help manage the Material in this application?
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Irregular head of material Gradation changes in the mix design will effect how a screed reacts.
When you have an irregular head of Material, you can usually see the same imperfections in the Mat.
Feeder Placement This is one of the major problems in the field hands down!
When should I change my Feeder position? What benefit will I see from a different position?
Managing the Feed System The correct position as illustrated here, will cure many problems with your paving operation. Material that is not manageable will make a mat that is unmanageable.
This is easy don’t make it harder than it has to be.
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TOWPOINT
Feed Speed EXTENSION
FLOW GATE
CONVEYOR
VERTICAL
AUGERS OVERRIDE
STOP
CROWN
SET UP
STOP
STD
RUN
EMERGENCY STOP
FEED SPEED EMERGENCY SHUTOFF
STOP
TUNNEL EXTENSION
AUGERS LEFT
BERM
RUN
DECREASE
SLOPE
FEED SYSTEM
REV
GENERATOR
INCREASE
FEED MODE
RUN
RIGHT
SCREED CONTROL
HORN
SET UP
RUN
Managing the Feed System
Auger Height Auger height controls the head of material and is determined by mat thickness. Add 2 inches or 50mm to the loose thickness you are laying, or more for larger aggregates.
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Auger Adjustments The head of material is the asphalt that is carried in front of the screed There is no need to carry anymore material in front of the screed than is required to feed the entire length of the screed.
Augers break. Augers get worn out. Augers can be changed.
Adjusting the head of material. You should have an even amount of material across the auger chamber, and your augers should be running 100 % of the time.
Adjustments.
1 10
Looking across the tunnel will tell you a lot about the head of material. You could resolve this problem by adjusting the flow gates or slow down and adjust the pile height.
9
2 3 4
8 7 5 6
Pile Height
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Proper Pile Height What we see is the correct head of material and an even flow of material across the auger chamber. Augers need to run all the time… not one faster than the other….Equal amount flowing in and equal amount flowing out..
If it needs to be shoveled to make it to the end, then do it!
Augers Extension Auger extensions should always be used when wider paving is done. Some material designs may require additional auger extensions that would not be required when working with traditional material designs.
How will material stay contained, uniform and continuously move with out them?
The Art of the Start..
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Think of how much material…
Material Management Summary Key Points in Prevention of Segregation:
• Keep Material Contained • Prevent Excessive Rolling of Materials • Move Material in a Smooth Uniform Uninterrupted Manner.
What the Customer’s Demand Long Life Pavement Proper Sub-grade Substantial Structural life Pavement Smoothness No Material Segregation No Temperature Segregation Uniformity of Density Speed of Construction Minimizing Traffic Delays Low Price
That’s It…… Easy Enough!
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Constructing Smooth Pavement Whether new construction or rehabilitation, a. Good planning b. Communication c. Proper mix production d. Delivery e. Correct placement techniques These Key Steps are necessary to ensure a smooth HMA pavement.
Asphalt Plant Production We need to know how much asphalt can be produced for this job. The plant may be making asphalt for jobs other than just our job. The tonnage per hour that is available for your job is needed to calculate paver speed.
Number of Trucks needed
How many do I need to get through the day?
Am I going to have 20 deep and then wait an hour? Will I get one at a time? Will the drivers turn the corner and wait for their buddy or buddies? I need to be prepared to adjust my operation to insure a good mat quality under many different conditions…… Communication
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Job Layout
You may lay this job out and it be just how you like it until the crew see’s it. If there is a better way to make the job easier, then listen.
In the end you may have to make fewer passes to do the same job.
Job Layout Great Example!!
Preparing for the job The paver size needs to be matched to production rates and job conditions. Now, not everybody has a fleet of pavers to choose from and you may just get what you get. If you have a job that is paving 10’ wide then use a 8’ paver when possible. (3m or 2.43m) If you open an 8 footer up to10, your operation will more than likely benefit. No 10’ paver likes to run closed up and no crew likes to run one that way..
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Paving width setup What typically happens is that you create pressure that builds on the extension. As we said earlier, if you have added pressure on the screed, you are not balanced.
Paving width setup As you can see here, it does happen. If you were to pave at this width you would see problems with the surface.
Existing Grade Conditions What the existing surface is like can determine many things that should be changed to balance production and maintain quality. Am I on a stone base that is loose or wet? I will need to explain to my drivers that you holding the brakes will not work. (this never get’s through) but yelling and blowing the horn always will…. For those with track machines, this is not a big issue but twisting the machine around on the material is an issue and should be raked over and smooth.
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It’s ok, it will cover Cover it, is not the answer here. Not all jobs are perfect but the customer needs to know what happens when jobs are rushed.
Existing Grade Conditions
Please don’t core here….
How hard can it be?? Our construction steps. Balance our production. Layout the job with a plan. Setup the machine to pave Pull off the joint Transition material, again balance your production. Make a joint. Match a joint
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What do we need to pull off?
If we just set down and pull off without any prep then we will go down. Setting down and getting the following in order will give us a successful takeoff. Allow for roll down. That means use starter plates…
Setup the paver for the application. This means width, tow point position, proper electronics setup.. Start with the correct head of material. This means what you start with should be what you use for the entire pull… Take your time before adjusting.
What do we need to pull off?
If we just set down and pull off without any prep then we will go down. Setting down and getting the following in order will give us a successful takeoff.
Execute proper material control. This means even after you start you need to keep an eye on your feed.. Check the joint with a straight edge. This means ensuring the joint is correct in both directions..
Mat Thickness Chart To achieve the proper Mat thickness, you should always allow for roll down. Roll down is the differential between the non–compacted and compacted material.
To Achieve Final Mat Thickness: 1” or 25.4 mm 2” or 50.8 mm 3” or 76.2 mm 4” or 101.6 mm
Requires an Initial Thickness Of: 1.26” or 32.0 mm 2.53” or 64.3 mm 3.79” or 96.3 mm 5.05” or 128.3 mm
Mat Thickness Chart
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Set the tow-point
Wash Down
Where should this Tow-Point be set? There are times that this will depend on the thickness of the mat, but a good rule to follow is 1 inch above the loose mat thickness
Pulling Off Allow for your roll down. Set the screed down and pull the slack out of the tow arm. Why is there a need to pull the paver forward?
Null out the screed, using both screws together.
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Add angle of attack
Pulling Off Load your auger chamber with material. Here is a great example of containing your material as you take off. Make sure that you don’t fill the auger chamber until it builds a mountain of material.
Zero out
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Zero out
Make sure you have zero
Go to automatic
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Auto on
Offset if needed after you check..
Offset if needed after you check..
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Don’t set yourself up to fail.
¾” Start plate
Start plates should be as long as the screed is deep.
Use a straight-edge Most foreman have a straight-edge on a service truck, but for the most part they seldom get used. This is a very important tool in the joint construction process. Using a straight-edge will help increase the quality of the joint’s as well as crown adjusting, sloped extensions and vertical.
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Use a straight-edge
Joint Prep. Good example of taking off on the header, except too much material was brushed up on the mat. The result is segregation and will change the thickness of the mat. The solution is to remove the larger rock.
Joint Prep.
Very little has to be done to this joint after pulling off because the setups were done properly. If you have a joint that is too thick, you have problems. The spreading or broadcasting of material is what will more than likely cause a failed joint.
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Checking depth and yield When correct depth is the most important thing, then what happens here? This spillage will gain ¾ of an inch in depth at this area. (19mm)
If you only have X to put down then pay attention to what is going on around you
Trucking Issues.. I want my MTV !!
Stopping Cost Money!
35’ / min * 60 min= 2100’ / HR 150’ stop for 2.5 min Down to 875’ / HR
Production
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Day 1 Infrared Data – 1000 ft. by 12 ft. lane Cold spots (blue) at 130 ft. intervals (truck ends)
Dump Person
Be sure the truck driver and the paver operator know when you are between them. Communicate well with the truck driver when it comes time to pull out in live traffic. Make sure it is safe. Takes tickets from drivers Keep unwanted material off the road in front of the paver Looks out for power lines and limbs
Truck Exchanges 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.
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Truck transition’s Dumping material in front of the paver as the truck pulls away can cause the paver to ride over the pile of material with adverse effects on mat quality.
When should I empty the Hopper? When you limit the amount of times you empty the hopper, you will have a much better Mat quality.
Stop the paver before the material drops below flow gate. Set and keep the conveyor deck covered with a minimum of 6 to 10 inches of material. (152-254mm)
When should I empty the Hopper? When working with segregating materials, the hopper wings should only be cycled with the hopper relatively full. This bunches the segregated materials that collect in the hopper wings instead of flipping them into an empty center area.
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Stopping and Starting It is recommended that you stop the paver as quickly as possible and accelerate as quickly as without being erratic.
This helps not only to minimize mat deviations, but also to maintain a constant, uniform head of material.
Segregation
Thermal Segregation is one of the reasons that asphalt pavement prematurely fails. Aggregate Size Segregation is caused by the same delivery vehicle as Thermal.
Why Use a MTV
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Infrared Data – with MTV
Proper material transfer If the insert is always out or low, you will see the same problem with Material Segregation. Might as well use a truck….
RP195
What about the Insert? 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. If the insert is always out or low you will see problems with Material Segregation.
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Why Use a MTV??
The Prosecution rests !!
Joint Prep. This is a good example of a header. It is cut back far enough where the paver laid a good mat, they will have a good joint for the next day.
Joint Matching The first rule of joint matching might be to avoid creating situations which promote failure. If the crew cannot accurately match the joint during placement , then joint is doomed to failure.
JOINT FAILURE AHEAD
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Joint Matching
If the roll down factor is correct, you may not even touch the material. If the correct steps are taken you should not have to touch the joint.
Joint Matching
Joint Matching Can we joint match with a ski?? Absolutely…
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Joint Matching Align the screed with the end gate overlapping no more than one inch on the existing joint.
Make sure your joint matcher is in the correct position. Remember the closer you are to the augers, the more reactive your screed is.
Joint Matching As you lower the screed onto the shims needed, check the end gate so that it is free to float up and down on the ground.
RP195
Joint Matching
Free to float up and down on the ground.
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Joint Prep. Proper joint solutions involve the following: Eliminate the joint altogether. Echelon paving. Proper mat overlap.
Joint Prep.
Segregation Even though material has been successfully processed through the cold feed bin, the plant, the surge or storage bin, then uniformly loaded on the truck, segregation can still occur in the paver.
Improper operation of a paver can cause segregation in varying degrees.
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End of load
Mat Quality and Texture This mat (under extension) is too tight and shiny: The angle of attack jack should be turned approximately one revolution counter clockwise to push the bull nose down to decrease mix feeding under the screed extension, thus transferring more weight to the main screed.
Mat Quality and Texture By adjusting the extensions to tighten the Mat, you will notice changes in the Texture. Clockwise tightens the Mat. Counter Clockwise loosens the Mat.
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Send in the Mill What Happened to the Margin?
A great start for a strong joint
This picture tells a story..
90% of the time things are good It’s that 10 % that gets you every time…
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What Happened When I ? Put my controller into Automatic and the Tow-point shot to the bottom. Started into a super and the mat on the left side got very loose and the tow-point shot to the bottom. Set my sensor up on our string and the sensor will not lock on. Came to a stop and a crew member leaned on the string and the tow-point moved. Came to a stop and the feed system over filled. Came to a stop by turning the speed pot and all the sensors were still working. Was running slope and the material was getting too thin on the slope side. Was averaging and getting a variable depth. Plugged in my control box and the display was blank. Put my foot under the sensor and the tow-point moved up. Decided that I needed to adjust the system and now the system will not work.
Pave by the numbers. 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. 16. 17. 18. 19. 20.
Heat the screed. Set the tow points. Set the paving width. Set the crown height. Set extension height. Set extension slope. Set screed, remove slack. Null the screed. Position end gates. Set auger height. Fill the auger chamber. Adjust the feeder controls. Set accessory functions. Pull off with starter blocks. Double check settings. Adjust the grade system. Null or survey controls. Go to automatic. Start slow and consistent. Adjust depth as needed.
Thank you Outstanding leaders go out of their way to boost the self-esteem of their personnel. If people believe in themselves, it's amazing what they can accomplish.
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Thank You Session Evaluations/PDH’s
See you again at:
• Professional Development Hours logged in session feedback.
• World of Asphalt 2019
• Complete session feedback in mobile app.
• February 12-14, 2019 • Indianapolis, IN
• CONEXPO – CON/AGG 2020 • March 10-14, 2020 • Las Vegas, NV • 140+ education sessions
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