Thread: Filling holes in a gravel driveway

Here in Australia our road builders use what is called road base and Granite road base is the best and they roll it with heavy vibrating rollers along with what is called sheepsfoot rollers which really compacts the road base.

The other thing is that it needs to be built up above the natural ground level so that the water will run off instead of ponding.

To stabilize it and repel water from the road they mix the road base with lime.

I don't think you will ever get to this standard with out some heavy equipment.

You're right... that's bad. It's not a hole, it's a "wash."

Filling with dirt isn't a viable long-term repair, (it's barely short-term) and loose aggregate isn't much better. Barry's right... you need to fill the bottom with a suitable material and compact it down.

The material we use tends to vary depending on what's available locally, but the best I've come across is a sedimentary rock that's composed of about 50:50 sand:clay. It breaks down to a sandy state fairly easily with a hammer, but with compacting and the first rain it sets again to a cement-like product. Bloody good stuff! I've no idea what you'd call it over there... but I'm sure your suppliers would be able to recommend something. (We call it "bag" but that's just verbal shorthand for base aggregate. Another council I worked for called it Salamander, I've no idea why...)

No real need for heavy machinery, like sheeps-foot rollers, etc. at that scale though... you should be able to rent a wacker-packer from somewhere near you... go for a tamper rammer (I believe you lot call 'em jumping jacks? Hops about on one foot, anyway. ) instead of a vibrating plate or drum. Lay a max of 2" of material, then compact until a pencil dropped from shoulder height won't leave a noticeable indent. Repeat with the more layers until you reach the height you want and finally apply a thin layer of gravel toppings and compact that in, to give any further toppings something to "key" to.

A hard day's work, but it should outlast you and your children, unless it sees really heavy traffic.


(Can you tell that I've spent all too many hours leaning on a shovel? )

Barry is correct the road is too low and needs to be built up above the surrounding ground so it can shed water, with drains on either side to carry water away should the area be as boggy as it looks. You should only need a clay/sand aggregate mix to raise the road topped possibly with fine gravel or crushed stone to give a decent surface. I'd start by getting in a local earthmoving contractor in to have a look, you don't need highway specs, just standard farmyard tracks. Your local quarries will dictate the material as freighting in from a distance can be very expensive. Dirt is usually a waste of time but it does depend on soil type and your local soils may be adequate for the task of raising up, but you will need some crushed rock or similar for the top regardless.

I'll go along with Barry and say you need some help to get it done properly, a contractor with some equipment. The hole behind you in the photo could use 4 or 5 tonne of road base to get it right.

Otherwise, get a few loads of gravel, hire a bob cat and spread it out. Then hire a roller and finish it yourself. Build it up with good road base gravel in layers as said.
I would try to hire one of the pedestrian rollers. A single steel drum about 900 wide that you walk behind.
The trick with them is to roll and rake until the gravel is fairly compact and flat without the vibrator on, then finish it off with the vibrator.

Skew, I can't agree with you about the wacker packer, in my experience they work great in trenches etc but no as good as a roller on large flat bits. Of course the cost is different. What we call road gravel up here sound like what you are describing. It is material that would become rock eventually if we left it alone.

You need to get your gravel at just the right moisture content. Water it down and let the water soak in. Over night if you can.
If you get a hand full of moist gravel and squeeze it, no water should come out, and you should be left with a firm compact ball with the imprints of your fingers clearly moulded in.

Barry the lime tip is a new one on me, it is similar to what we used to do with a few bags of cement raked into the top layer of gravel. The gravel being moist hardened the mix after a while. Cement stabilised gravel contains only 3 to 5% cement.

Another stuff we used to use for this sort of work was cracker dust. That is the fine dust and sand like chips of stone that is left after stone for concrete has been crushed. Sets like rock if done well.
Regards
Bill

There is a mix of clay and crushed gravel called AP20 that is pretty standard here. You need to rip out the perimeter of the hole a bit (pick)and put this stuff in, drive over it a bit with the heaviest vehicle around. But Barry nailed it - you have to get the road above the immediate surround. A grader blade is a useful accessory.... keep the drive manicured otherwise you got corrugations and potholes and puddles... these all have an impact on resale value . Hence you need a tractor and grader blade and 75 yards of AP20 or equivalent.

Matt

In my early career we used 'cement stabilised crushed rock' for filling the trenches cut in paved roads and that was very effective but needed to be compacted as others have already advised. This was basalt rock crushed to a max of about 1/2" diameter and smaller mixed with a small amount of cement.

The other option may be to avoid getting water on the driveway. We have a pretty effective solution in Aus - called a drought. Has been known to last for 5 or six years or more. Reckon we have just about finished with ours maybe we could send it over!

As already noted, raising the profile will most effectively encourage drainage and reduce degradation. That's why they're called "highways" after all. Depending on how much you want to invest, I'd consider placing a stabilization fabric between the gravel and the subgrade. This can reduce or eliminate mixing of the gravel and the subgrade, as well as rutting or washboarding. Google [geotextile driveway] for some less heroic materials for best economy. Possibly cheaper, although somewhat less effective, would be a layer of filter fabric; but use contractor grade, not just weed blocker.

Joe

3% stablilised crushed rock (20mm down to fines) will fix those driveway holes.

3 or so 40kg bags of cement mixed through a cubic meter of crushed rock, local garden supplies should be able to mix it for you.

Originally Posted by MurrayD99

There is a mix of clay and crushed gravel called AP20 that is pretty standard here.

We call it DGB 20 here.

I prefer recycled road base nowdays. Not only are you helping the environment by not using a quarry product that is not renewable and reducing the waste stream but if you specify a DGB 20 mix (or what ever your local equivilent is) the crushed concrete in the mix, when given the correct amount of water and compacted dries rock hard - IMHO harder than normal road base. Oh and its heaps cheaper! Win Win Win.