This is an excellent material for the foundation of roads and slabs, as well as for backfilling. Knowing the sizes or grades of crushed stone and gravel is vital to help you decide the size you are going to buy, considering the intended use. Remember, the various projects such as drainage, driveway, patio, roads, decoration work, etc. require different sizes or grades of gravel and crushed stone.
In this post, we will discuss the common sizes or grades of gravel and crushed stone and tell you what size or grade to buy for what job. Gravel is a loose, fragmented rock formed by natural erosion and weathering. It is usually harvested in lakes, oceans, or river beds and has sizes ranging from granules to rocks. Due to gradual erosion, gravel has a soft shape and often has roughly rounded edges or shapes.
On the other hand, crushed stones are manufactured by crushing rocks into smaller pieces. Each of these types attracts different prices, and they have their pros and cons. Make sure you know exactly what you need. In addition, different rocks come in different colors, and the color you select influences the total cost you will incur.
In the United States, however, gravel can also mean crushed stones that are less than two inches in size but larger than sand. But the opposite is not true; that is, gravel is classified according to the size or diameter of the stone particles, and there are ten primary sizes and several other special categories. The exact name of each size may vary from place to place (country or state) or from one supplier to another. However, the particle diameter and uses are very similar, as is their application.
Secondly, grades do not tell you which stone was crushed; that is, thirdly, as a rule, the smaller the grade number, the coarser or larger the size of the gravel particles, and the larger the number, the finer it will be. However, this does not apply to the two single grades (or to some special categories), as we will see shortly. Let's take a look at popular gravel sizes or grades:
- Granules: 2 mm to 4 mm (0.079-0.157 inch)
- Pebbles: 4 mm to 64 mm (0.2-2.5 inch)
- Granulated Gravel: Very Fine & Fine
- Pebble Gravel: Small & Medium & Large
- Cobblestones: 64 mm to 256 mm (2.5 to 10.1 inch)
- Boulders: Larger than 256 mm (10.1 inch)
For example, crushed limestone will have a different price than crushed granite, marble, quartz, bluestone or white gravel. The presence of stone dust means that it is compactable and becomes stable and solid when compacted correctly. The Udden-Wentworth scale classifies gravel into granules with particle sizes from 2 mm to 4 mm (0.079-0.157 inch) or pebbles with particles from 4 mm to 64 mm (0.2-2.5 inch). Granulated gravel is subdivided into very fine and fine while pebble gravel has three subcategories; small & medium & large.
The Udden-Wentworth scale also considers unlithified cobblestones (which exist as individual pieces and not sedimented together) and rocks as gravel; cobblestones measure 64 mm to 256 mm (2.5 to 10.1 inch) while boulders are larger than 256 mm (10.1 inch). When purchasing any grade or size of gravel always refer to the supplier's description; check if your provider uses the same chart as we gave you earlier and if not explicit be sure to ask suppliers for actual sizes as different sizes have different uses. The ITEM 304 aggregate base is a grading system of the Ohio State Government that sets out the requirements or standards for various base aggregate materials below; provide OH slag having 0 to 10 percent passing through No 67 sieve size which has a maximum particle size of 3/4 inch (19mm). Due to its size and nature this material does not compact and is made to be machine-laid in uniform layers.