AASHTO #57 (coarse aggregate stone has 100% passing 1-1/2" screen, 95-100% passing 1" screen) is an open-graded, self-compacting aggregate blend of size 5, 6, & 7 stone. This material cannot be 'compacted' in a true sense, but can be properly oriented with compaction equipment.
So rather than compaction tests, #57 stone should have it's individual stone facets properly oriented using a plate compactor, jumping jack, or other vibratory compaction devices. Using compaction equipment, #57 stone will typically compact about one inch in vertical height, which is equivalent to about 8% settlement.
Self Binding Gravel is a blend of either 10mm or 8mm sized gravel particles, gravel dust, sand and clay that binds firmly when compacted. Not only does it look neat and attractive but it's also easy to maintain - just requiring the odd bit of weeding.
Crushed stone #57 refers to stone that is about ¾”. This is typically used for concrete mix, landscaping and drainage.
Our soil is similar to yours and both work well. 57 works better if you have a lot of water issues, as long as you run a tamper over it to consolidate. Crusher run or base rock work well with soils that tend to move more. You will need to add allot of water when you have it graded out in order to maximize compaction.
Dense Grade, also known as quarry stone, is a compact aggregate comprising small, crushed stones (3/4-inch or less) mixed with stone dust. Typically made from materials like limestone, granite-gneiss, or trap rock, it's designed to bind tightly and create a sturdy surface when compacted.
The author has not found any technical data published that demonstrates that gravel is densified by dumping. However, there are numerous claims in Internet discussion boards by some that gravels are “self-compacting,” but geotechnical engineer contributors generally disagree.
Generally speaking, each ton of #57 stone can cover an area spanning approximately 60 square feet at a depth of 4 inches. At a depth of three inches, a ton of this material can cover roughly 80 square feet, while it can cover an area of 120 square feet when it is placed at a depth of 2 inches.
RC-57 is another excellent option for French drains. It consists of smaller stones that can still facilitate good water drainage.
Rocks such as pea gravel or stone mulch provide an effective barrier against weed growth while being relatively simple to install and maintain. Gravel requires little maintenance once laid down; simply topping up small areas where necessary over time will suffice.
Wetting soil can reduce the amount of dust produced during compaction. In some cases it can also improve the quality of the compaction by helping the soil particles slide together more easily, However this step isn't always necessary. Granular soils with little or no clay can be compacted wet or dry.
Construction and Coverage
The sub-base should be not less than 75mm deep for foot traffic and at least 100mm thick for light vehicles. Once compacted, the self-binding gravel is spread over the surface to a depth of 40-50mm and then compacted.
The fill material can also be #57 stone or a similar ½”-¾” clean angular stone. All of these materials provide a 40% void space which is a common industry standard. The Iowa Stormwater Management Manual2 and Virginia DEQ Stormwater Design Specification No. 73 state the void ratio for #57 stone is 0.40.
Gravel Driveways – Properly graded and compacted #57 stone creates an extremely robust driveway or parking lot surface. The angular gravel locks together to create a stable base that can withstand heavy vehicle loads.
But, if you continue to hammer down on those rocks they will begin to break down into smaller pieces and eventually you'll end up with sand, which is completely different than what you started with. Over compaction breaks down the materials in the soil which ultimately can change the composition.
With proper care and maintenance, a gravel driveway can last up to 100 years. That's because there's just so little that can go wrong with gravel. Unlike a solid asphalt or concrete driveway, it's not going to crack or sink.
One of the most significant reasons this stone is in high demand is its size and porosity, which allow for rugged applications and drainage. AASHTO #57 will not compact. However, with vibratory compacting equipment, it will have slight vertical compaction that's necessary for certain applications.
Adding drainage to a backyard does not have to be a complicated project. One drainage solution might be installing dry-wells in the areas that tend to get the most water. A dry well is simply a deep hole filled with gravel to allow water to reach a more permeable soil.
The number “57” is a number that refers to the size sieve that was used to screen and sort the stone. It means that the stone was put through the #57 sieve which produces gravel stones of about 1” to 1.5” in size. #1 crushed stone refers to the largest sized crushed stone. It is about 2″ to 4″ in size.
The best size gravel aggregate for your driveway ranges from ¼” – 1” because it clumps together better when a tire presses on it, so the result is a more stable and less slippery surface. It's also great for drainage, ensuring you won't end up with a pond instead of a driveway.
One truckload of this rock is roughly equal to 10 to 12 cubic yards or 16 tons and may cost around $800, although prices can fluctuate. Dirt Connections currently offers this type of stone in increments of half a truckload.
You don't necessarily need to wet gravel before compacting, however a light amount of water can help to keep dust levels down. Just be sure not to make the area too wet.
Dense Grade Gravel
When compacted, this is a type of gravel that hardens like concrete and forms a semisolid surface that's able to stand up to the rigors of vehicle and foot traffic. This type of gravel is considered practical and functional, but not exactly aesthetically pleasing.
Cedec Gravel
This type of self binding gravel is commonly seen on areas where a dash of red looks appealing and stunning, Cedec gravel is made up of both quartz and granite.