im having extreme problems getting the proper compaction on this particular dirt.if anyone has any suggestions please let me no?the p.i. index 14.5+or- dirt density is111.9.one minute its too wet next test too dry.we haved turned this dirt so much its pitiful.the testing lab guy actually broke his rod extractor pulling his pin....but he says its too soft.
Some dirt will just not compact no matter how much water or compaction you run over it. I've seen this in Wyoming and Colorado, where some excavated soils actually swell with increased compaction efforts. Ames Construction had a huge problem with very situation at the new Denver Airport when they were doing the site-ex back in the early 90's. They actually placed more cubic yards of fill than they excavated. About all I've ever seen that worked, was to water the crap out of the fill, then move off for a while (days or weeks) and let the water work it's way thorough. The water draws the fine soil particles together as it moves out and the soil takes a set. This situation was also a big factor on the Route 41 extension fills north of Fresno near the new Children's Hospital. Lots of fines in the excavated material soaked up a huge amount of water, plus the superintendent was allowing the lifts to go in too thick with 651E's. The result was massive soft spots that no amount of compaction would solidify. The ground actually rolled under the weight of a loaded 51 for several feet in every direction. Standing nearby was like being in an earthquake. The solution there was to dig up the soft spots in the fill, rip as deep as possible in the bottom of the trenches, them leave the spot to drain and dry out for several days. Then the removed material was dozed back into place in thin lifts with just a touch of water and compacted tightly. In Wyoming at a Kerr-McGee Uranium stamping plant site, 651B's were loaded and run over the future site of the stamp all day. This fill was 6-8 feet thick. The Proctor rating actually went down and the best test was about 98 percent density, but it wouldn't stay that high and a few more passes would result in an 96 or a 95. We moved off the fill for a week and then went back for another test. It came in at 99.8 and the inspector was happy. Don't feel bad, this is a common problem in many areas of the U.S. Good Luck!
Red oxide soils. Hi, White Boyz1, Firstly, welcome to the forum. We have some of those red oxide soils DownUnder too and they are just as much of a problem to compact. Moisture is very hard to get right and especially evenly right through the 'brew'. Even minimal compaction tends to render it largely waterproof. The best method I've seen for getting water into it evenly is to use a Pulveriser, a large rotary hoe-type machine often used for lime or cement stabilisation, which has metered water adding equipment fitted so that it can add the water as it is rotary hoeing the material, thus mixing it thoroughly at the same time. This usually requires that a water truck be connected to the Pulveriser as it is working the soil. These soils also tend to 'bridge' very easily which means that they need to be compacted in thinner layers than many other soils, often in layers as thin as 3-4" at a time. Sheepsfoot compactors seem to be the order of the day and do NOT attempt to over-compact as this will bring you undone almost every time. Surfer Joe mentioned above what often happens with over-compacting. Another problem is that when the moisture content is right, the material tends to become very sticky and will quickly clog a sheepsfoot compactor's rolls if the scraper bars are not in good order and correctly adjusted. One more little hint - when I've had to work this stuff to specs., I've had more success testing density with a Troxler unit than with penetrometers. It seems that the penetrometer rod will pass through this sort of material quite easily even though it is quite well compacted because of the uniformly small size of the particles. Sand replacement testing has to be done carefully too, making sure that the samples taken back to lab. for tesing there don't dry out in transit. If this happens, it will throw the weighing off dramatically. Hope this helps.
Do you have or are you using a disk and working the fill by disking.Also are you using a blade on the fill or just using a dozer on the fill. I'd try disking and using a blade and figure out what is working as far as test goes if you need to disk then let dry or disk add water or both. Light lifts with would be needed for sure if you having problems with the test ,no hogging the dirt in there to fast.Got any other dirt where you could mix with it to help???? Like others says if you have other places to fill you might have to move on down the line and then come back. Do you have to pay for every test,i have had to do that before,but if not the more test the better you could tell if something is working after each trial and error method.Good luck for sure:usa
We have used ag lime to help stabilize the soil, but it takes a lot to do it rite, You can use Bentonite at about 4-6lbs per sq-ft but its not cheap. Spread it on, disc it in, then compact and the soil will get as hard as concrete.
hey dogg :drinkup thanks for the info .no we dont have a disk on the job,but we do have two d6n's one plowing and one blading.13 trucks,one 84''sheepsfoot,one 72'' sheep ,one water truck,three stiegers with double 17yrd pans,and one 8950 with a 12yrd pan that we fill with dirt and kinda seal things off with..but on the better note i think ive solved the problem.its seems that those guys get paid every trip out?but the problem was the red oxide dirt has a high consentration of iron which is a big problem for the troxler machine.it dont like iron at all...............................final lift results 115dd,126.5wd,14.5m,96%=all test passed.......thanks for the help guys..