I am finishing up a rather large job this week and have a sub coming into pave like 1200' of road. They bid it putting it in at 2" thick base course and 1.5" wearing course. How do I measure and make sure I get the 2" min on the base course? Is there a method of checking it before rolling? Like if I had a screwdriver in and pushed it down what would the unrolled thickness be 2 3/4"? I have had core samples done before and was mssing asphalt that I got billed for. I was supposed to have 3" and I was lucking if there was 2 1/4". Hard to find good pavers these days. Most of the big companies up here got caught cheating the state out of mix.
I would say a thin rod would work good.
I am not an asphalt guy but you should see about an inch of compaction. The paving machine screeds must be set for the required thickness right? just check with the operators there to see what thickness there laying. If you can't trust them for an honest answer you should'nt do business with them.
So they would need to lay almost 3" done to get a compacted 2"? I wonder if there is a formula that would give the exact amount? I just want to be able to spot check. Face it a 1/4" thickness difference over 1200' of road adds up probably to a almost a full load of mix. The more they cheat the more they make.
Thats exactly it too, keep an eye on them. Check the bid, make sure it states two inches of COMPACTED base. Make sure it it says 1.5 inches of COMPACTED wear material. If they dont put this in the bid, your at their will. The best thing i can recomend is going with someone who has good recomendations in your area. Im not sure about your part of the country, but here its starting to get nice out, so i would imagine the gypsy pavers from the south will be working their way north. Watch out for these guys, they seem to be the real fly by nighters.
General rule of thumb is 1/4" per inch on mat thickness prior to being rolled.
Thanks Diggindoug so I should be looking for around 2.5" uncompacted. I will make a gauge I can just stick in and quickly check. Maybe use a piece of wire.
1/4 per inch is good rule of thumb as stated before. You can use 5/16th threaded rod with a nut then a plate and then a nut, you set the depth with the small plate the tighten the nuts up against the plate, we call them pokey sticks. 2 inches of base seems light for a drive way/ road. If it was my road I wouldn't let to many trucks over it with only 2 inches of BCBC or 25mm. Something to consider is one loaded Tractor trailer is equal to 11,950 cars. Just my .02 cents telescooper
You could use the same grade stakes that were used to prepare the road for paving.Just subtract the pavement thickness from the dimension that was used to determine the subgrade.Maybe you might want to take a few readings before they pave for a reference.Generally the reading you get in the gutter and the crown are the only meaningful measurments as those are the readings we use when preparing the base for paving. If your sub base is off then you will get an argument from the paving crew if you question their work.The grade that you see on the grade stake will usually be "FG" finish grade in the center of the road after all paving has been finished.You have to do the calculations for the gutter grade depending on how much crown is specified and you use the same grade stakes when laying the gravel and processed stone.The end result has to be pretty close to make the drainage work etc.Ron G
Yeah you are right about the fly by nighters. I learned a lot from this topic, had a guy come over and he was doing a drive way up the street and he was saying he didn't want to loose the materials since they harden, I have a large driveway and he quoted me as 3,800 for my large area. Well it sounded good but many times these paver cats use the minimul amount and in a few years you have cracks and whatnot. So I asked what the depth would be after compact, he said two inches and I didn't think it would be thing enough over the long haul to prevent cracking. I understand things wear and crack over time I just didn't want it to crack right away.
Xcavate I just use a stick ruler to check depth as we're going...and yes you need to check, but also remember they have a tolerance just like on the grading, I'm not saying let them cheat but keep that in mind...
Take a grade stake or piece of wood and drive a nail in it at the depth you want.Also if you get the slips for total tonage it should about 615 tons for the base thats just quick math could be wrong.Keep an eye on them i just got a price for 1200 ft of road $63.00 ton put in place.. glen
Paving Insight Xcavate, There are some good ideas above, 1. For every inch of asphalt there is a 1/4" of compaction ( 2" comp should technically be laid at 2-1/2", but keep in mind that roughly about 70% or so of the compaction comes from the paver screed so it's not necessarily going to be 2-1/2 behind the paver.) 2. Keep in mind you are shooting for an average of 2" of binder.....regardless of how good the grader operator is there will be imperfections in the base. They should get close but it's not building a watch type tolerance! 3. Most county roads or commercial lots are no more than 3" total depth. (And by the way as to 25mm binder shouldn't be laid at 2", I can't remember 100% but I think the recommended minimum is like 2-1/2 or 3") More than likely they will be using a 3/4" or 19mm binder. 4. Just watch to see if the screed guys are probing what behind them.......if not then I would start checking it myself. All-thread and double nut, nothing fancy. 5. I would collect a copy of the load tickets from each truck as they back into the paver. (Just like an inspector would) Just as a reference to you to figure yield: 1 SY of asphalt 1" thick weight 110LBS. Example: 20' wide x 1200' long =2400SF divide by 9 =2667SY 2667 SY x 220 (2" of is 220LBS) =586,740lbs divided by 2000lbs = 293.37 ton There will be people with 20 other formulas but after 16 years of paving it is the one that works for me in the field and when bidding. I hope I was some help to you. Good luck!
Inspection ? Well, if you are not knowledgeable, I would consider hiring an Inspection service firm to make sure they comply with the specs in the contract. Cheap insurance ! It's called Quality Control . If your client is on the ball he will do just that, after the fact. Any deficiences will cost you ! Of course if there is no more than an eyeball inspection. Then you can cheat all you want till your reputation catches you. The subgrade has to be graded accurately, otherwise the 2" base course is just a leveling course. Then other contractors say, just make up the grading errors with asphalt, yea right my ass. Costly grading errors ! Asphalt specs, you ought to know them by heart . 2" of laid down compacted finish grade asphalt. They (Laboratories) cut donuts,or cookies, out to check for densities and correct finish thickness. No cheating allowed here ! ASPHALT04, has good advice.
Lots of good advice has been given. Give this a thought, pay for your asphalt by the ton, not the square yard. You'll have the other problem, thicker than you want, but that's a good thing The screed man will be cranking up instead of down. We (the owner and inspector) use cheap 6 inch wood rulers to stick in the asphalt. We walk behind checking and when we get the thickness where we want it, I threaten the screed man with bodily harm if he touches the screw again . Calculate how far a load will go and spray paint lines on the gravel. It takes constant vigilance to get what you are / should be paying for. I had a job where the paving foreman took advantage of my brand new inspector, he had 2/3's of the tonnage used, halfway through the job . We ended up over on tonnage but I paid for it. I told the paving company supervisor, if his foreman ever did that again on one of my jobs, I was only going to pay for what I calculated the tonnage to be and his foreman would be arrested for trespassing if he ever set foot on one of our jobs again. Amazing how conscientious they became. End of issues with that company
I wish I could use my normal paving guy. This job is to big for him. He would have to do the road in 3 passes with his machine. He normally just does driveways and small parking lots. The company the is doing the paving also owns the fine grading. In my contract it says I have to get it +/- 1" and they take it from there. That way if there are puddles I have somone to blame.
If the paver has to make 3 pulls, when doing the job, make sure the joints on the top course are staggered over the base course. telescooper
I agree with staggering. I like to see even if only 2 pulls staggering by at least a couple of inches from binder longitudinal joint.