I would like to hear what the group has to offer for measuring compaction of lifts during building up a pad, road, ect. I know you can hire the soil geologist to come out, but I want to know before they get there. They charge if you fail a compaction test and you pay for any further testing required. I would like keep the cost as moderate as possible, hopefully under 2k. I have done some research online but have only found professional machines costing many times more than our budget. Would love to hear from anyone with experience or tips Chris
We always do a proof roll test. This is where you drive a loaded dump truck over the area and see if the soil/gravel, etc. yields or pumps.
Chris what type of project are you on ? How much fill ? and what type of fill are you placing? What dept are you filling? If you want pm me and I will reply if you want to keep it private.
My testor is a 4' sharpened probe with a T handle, well under the $2K
If we don't have a tandem, I have a homemade probe in the truck. My dirt doc trusts a loaded tandem better than a nuke gauge. If we are buildling something structural like a retaining wall or building pad the tandem is always the final seal of approval. Chris what part of the state are you working in?
You wont find a cheap nuke gauge. They have to be registered because they contain radioactive material. The person who uses the machine has to be trained and certified. Then, if something were to happen to the machine where it is damaged, you have a whole new world of trouble. I believe I have seen stories that some manufacturers machines are out with technology that shows you what you have compacted has reached density. Not sure how it works, or how accurate/reliable it is.
Yeagh we have used the tandem dump truck test. I was wanting something that was a little more scientific. I seen testers that had a t handle and a prope that you pushed in the ground, it had a gauge that read in psi. I thought it could be something that would indicate if had reached 90% or 95% compaction. I have failed comaction test by as little as 3% and had to disk and recompact. The projects Im working on are basic pad jobs like commercial lots, small subdivisions, ect. CM1995 its not what part of alabama im working in, its what part of the southeast With challenging times we are very mobile. Right now Im around tuscaloosa al
I've all ways been a believer in that a good hand will know if he has compaction before any test can be done. You could do Sand Coning that is how they did it way back in the day. I'm not sure where to tell you here to start looking for all of the info you will need to know. Basically you dig a small hole in the compacted material clean it up real good. Then weigh ALL of the spoils. Then using a sand cone with a known weigh of silica sand fill the hole and weigh whats left in the cone. With some math you can figure compaction cook the moisture out of the dirt and you can tell moisture with some more math. We have had to have this done in areas that where contaminated with hydrocarbons its a timely process especially if there are lot of different materials(dirt) on site.
You won't find something that reads in terms of % compaction because that percentage is determined by a proctor test, which is a series of lab tests where you determine the optimum density & moisture of the particular material you are working in. A proof roll or the T-Probe method was my quick check method when on site. Depending on if you work with the same testing company if you get on their good side they may be willing to work with you on tests. We worked with a couple of crews that we followed around all the time and if they were low on compaction and I wasn't in a hurry I wouldn't bother to report the test and let them keep working it and retest. As was mentioned, you won't find a nuke gauge for contractor use. You do not want to bother with the hassle. Trust me. The paperwork you need is insane and traveling across state borders is a serious hassle. Our gauges had to be secured to the trucks as far as possible from the driver. We chained it to both sides of the bed with 2 different padlocks. The gauge itself had 3 locks on it which was a different key than the tiedowns. You have to log the gauge in and out, store it in a completely secure area, and wear a dosimeter. I don't want to imagine what the insurance was on those things either. The sand cone is an option but you still have to know the proctor values in order to know where you are in terms of % compaction.
I know at least 2 local contractors with their own nukes. Both are asphalt paving companies. I work for an earthwork company, I asked if we should get a nuke because I've gone to school for civil tech and know how to do proctors and know how to use a nuke. Our project manager said it's not worth the hassle, since 9/11 it's become a pain in the butt owning those things.
I thought there was a tester that had a specific weighted rod that you lifted to a certain preset height and droped x number of times and by measuring how far it went in the ground gave you some kind of number to get a compaction estimate. Am i just dreaming this?
There is something like that we use testing the bottom of the drill shafts for piers, but I don't think it has any relation to compaction really.
Your not dreaming this. I dealt with this for the first time last fall. The dirt cop used a set up like you are speaking about to determine the grounds ability to bear the building load in the footings line. It didnt really seem to be used to test compaction, as he used it in a footing that was cut in natural ground.
Please see attached links,,,,copy and paste to address bar http://elearning.najah.edu/OldData/docs/Sand Cone Method.doc http://geotech.uta.edu/lab/Main/SandCone/index.htm There is another method used called the "Balloon Method", both the balloon method and sand method were used prior to nuclear gauges being invented. I have overseen many projects requiring from 100% to 90% compaction for clays, silts, granulars and pit run materials unfortunately there is no one simple answer to guess where your compaction is at without using a nuclear gauge together with a proctor performed in the lab. If it helps I tell equipment operators on a granualr grade, as a general rule, give me a minimum of 6 passes (using a rubber tire Bomag, 2.5m steel drum). Depending on instu moisture content the area to be compacted should be given a healthy dose of water prior to compacting. Using 6 passes you can acheive close to 90% compaction or more only if your lift thickness is a maximum of one foot, 6 inches is better using full vibration on the packer. I have not known of any hand held devices (probes) that will work effectively to give you an adequate indication of compaction, because not only do you need to acheive % compaction, it also has to have the proper moisture content to get it. A steel rod driven into the ground will not tell you your % compaction/moisture content. Only time I like to use a steel rods is when witching for water. Usually a pair of straightened out coat hangers works great. I once performed compaction tests using the sand method, it sucked, and it was my last time.....lol hope this helps
I don't know too much about them nukes but what I do know is that if your proctor is off you are SCREWED. Were building a road one time and the only way we could reach spec on the road top was if we had the 815 and a 84 vibratory packing behind ONE scraper. Finally the bosses sent some dirt in to a different lab and the proctor was way off.
im with abscraperguy.. if a lab geek forgot to carry the one then you are screwed... unless it is a state job we always use the proof role as the final say. i have watched many nuke guys change the guage settings to get the right compaction because the material was becoming over worked and it was just the moisture content that was throwing it off... plus we could take a d6 over it and the grousers hardly made a mark and he figured it was hard enough lol
We did a project next to I20/59 a while back. We had the red sandy/clay and it's a good blading material but if it's too wet you can't do much with it structurally. Had moisture problems on that job and we found an agg supply over in Northport that had a spreader truck. 3 applications of around 5 tons and we were good to go. If you have any influence over the selection of a geo-tech, PM me. I have a very good company out of Birmingham that is great to work with, they monitored the above mentioned project.
that isn't because of the nuke...if the proctor is off...it's off for a sand cone test, balloon air, etc....all the proctor is data taken to the field from the lab telling the tech what the maximum dry density per cubic yard and and what moisture content is needed to achieve that goal. skewed lab data....skewed field results.
poor lab techs or field techs can make a job miserable...that's for sure. ...typically, it's not the machine taking the test's failure...it's poor lab data, or poor field testing ....years ago, i had a highly respected soils engineer once reply to my..."look no tracks are being left" comment... his reply....."there is a difference between being dense....and being hard, i want density first"
Did you ask him which he thought he was..............., just before you hit him with a digger bucket.
no, what he said was spot on.....there is a heckuva difference between hard and dense. maybe i didn't explain myself well enough there. since then and my experiences with soils..he was absolutely right!
"Compaction" test are really density test. Hardness of the material in most cases is a direct corrolation of the density of a material. We have a great soil Engineer thats been in our area forever. He is great about explaining the how, what, why questions that you may have . Soils on the microscopic level are an interesting thing, it makes compaction a science and allows you to be efficient with compaction techniques, not just rolling till its "hard".
i do agree that you need density but when they tell you to add more water cuz the machine says so and the water is just making the soil pump and move i think that there is a problem.... i call it hydropacking when they want us to do that:Banghead
water is nothing more than a lubricant allowing the soil particles to slide together easier during the compaction process...that's why engineers like it, they like to see the soil put in a consistent moisture content where they have determined to be the optimum content to achieve it with the least effort. generally speaking....these guys aren't your enemies. i know, some are equipped with bad lab data, had a fight with wife that morning and have a chip on their shoulder...happens all the time. but their goal, AND should be yours...is to have an end result for the customer that is at your best ability to provide, and done so in a timely fashion..most engineers are not out there to harass you or cost you money, they're there to monitor the quality of your work. the intent of them on the project is to insure the owner of a quality product, and to assist the contractor by relating what their lab results have given. soil techs are employees of the engineering firm that bear all the costs (taxes/ins./vehicles/shop space/office space, etc. etc.....that employees of a construction company does...they want them in and out of that project as quickly as possible. my experience in the 29 years i've been in business is....you go 40% of the way, if you're effort is sincere, ..show good intent/effort...they'll bend over backwards to come the other 60% to help you, not deter you.
an added note...a lot of "hack" contractor's in the underground biz...consider compaction to be a loser, whine about it...that's why i LOVE a tough soils engineer on the job and having the reputation of being so...i like hearing some guy coming in and low balling a job to get it in the hopes of having a no show/passive/weak soils engineer only to get their balls busted and have to do the job properly and lose their tush...we view compaction as a pay item just as we do with the excavation, and installation of the pipe and bid accordingly.
I agree 100% with this. These are guys with zero experience in the actual mechanical aspects of the structure. This is the same reason I don't like to see demolition companies with no idea how to actually CONSTRUCT the building. If you are not familiar with at least the basic fundamentals of construction, you don't belong on the job.
...lol dayexco,,I didn't know you felt that way about me sorry, I couldn't resist.... although I am not an engineer, I am going to ensure that compaction is done correctly and according to spec., if I hear any whinning, I just ask the Contractor to put his concerns in a letter, funny I have never received a letter yet..wonder why.
I am a soil Tech and run around here with a Nuke. I also work for a small compant so I do the Procter and Concrete and asphalt testing. I like that it varies so much. Four years ago I was up to Construction superintendantbut got sick of living out of the suit case. The nuke and procter for processed aggregates (and Asphalt)like class A or Type one it is a excellent tool and works well with. However the problem arrises is with natural fills like pit runs and clays. A procter is taking representative sample and jamming it in a 6" mold, one little stone here makes a huge difference either way. The other problem is with larger materials , it is not represenative. is the rod against a rock or void 1 foot down. I try to work with the contractors I deal with. I proof roll most times but I need to use the nuke to document in case something happens 20 years from now and then everyone is covered. The way I proof roll is have a tandem, roller or even a big plate tamper go over the area in question and I look for the ground not to sping back after loading is off. Dispite what Bomag, Dynapac and the rest of the guys tell you. you Cannot compact to a passing grade with more then a one foot lift. I just had to prove this to a contractor and the Cat rental guy this week. they tried to tell me that the big Cat roller could compact in 3 foot lifts. so I had them put in a 3 foot lift like they wanted and had them beat it like they owed them money then dig down 2 feet and ti was 85% well guess they had to dig it all out. The Class A or Type 1 in this area is 7.5 - 8.5 % uptimum moisture and a matimum dry density of 2150 - 2200 Kg/m3.
Well said. Geotechs are there to cover our ass, the owner and themselves. They are an important part of the project team. Correct documentation of your part of the project is invaluable in the event something goes wrong later down the line. Attorneys us the shotgun approach and proper documentation of compaction testing meeting specs may keep you out of the courtroom. I am fortunate to have a geotech company I have worked many projects with. The owner and 2nd in charge are just a phone call away to make a site visit if we run into something we didn't expect or are having problems meeting compaction. The soils in our working area vary greatly, even on the same site. Several times we have had to take more proctors due to changing materials. This particular firm has done work on past projects for myself and I have recommended them to many GC's to use as well. Some of the bids I lost but they ended up working on the project. Later they told us they wished we had gotten the job.:cool2
It all depends on the material and how you work it.
No prob, I gotcha first time, it just struck me that the man was maybe too sharp and needed a bucket to realign his attitude but it obviously worked for you :thumbsup :jawdrop ................ opcorn
Anhydrous applications to aid in compaction? maybe other members of HEF can help me out on this.........here is what I've been told. At a local fertilizer meeting the statement was made that during WWII the US Gov used Anhydrous Ammonia as an aid in construction of runways for the planes in the South pacific. the claim by the fertilizer rep was that Anhydrous basicly killed off microbes in the soil thus aiding in the compaction of runways. Has anyone ever heard of this method to aid in compaction? If so, are there other similar chemical aids employed in today's construction techniques? just wondering mostly and I do apologize for the hijacking of the thread. :beatsme
I have heard of that but never seen it in practice ,the theory is that where good, stable base material was unavailable by killing off the microbes the organics would not decay and there fore would hold as a base material it is however a short lived exercise.