Types of gravel and their sizes: 3/8, 3/4, 1 and 1½ inches

In Mexico, construction gravel is graded mainly into four sizes: 3/8, 3/4, 1 and 1½ inches, according to GCC's technical data sheet from August 2020. All crushed gravel for concrete must meet standard NMX-C-111-ONNCCE-2018, in force since November 12, 2018, and the right size depends on the element it will go into.

Key facts

• GCC produces crushed gravel in 3/8, 3/4, 1 and 1½ inches, per NMX-C-111-ONNCCE-2018.
• CEMEX classifies its 3/8" gravel as Sello 3A and its 3/4" as No. 67 (ASTM C-33).
• CEMEX's 1½" gravel corresponds to No. 467 in its own classification.
• 3/4" gravel weighs 1.45 to 1.50 t/m³ loose, per GCC (August 2020).
• NMX-C-111-ONNCCE-2018 has governed aggregates for hydraulic concrete since November 2018.

Are gravel and fine gravel the same thing?

Strictly speaking, "grava" is the technical name for coarse aggregate — larger than 4.75 mm — whether river-sourced or crushed. "Gravilla" has no separate standard-based definition: in the region's commercial use it is applied mainly to the finer fractions of that same coarse aggregate, such as the 3/8-inch size, which because of its size is handled and placed differently than 1 or 1½-inch gravel.

For standards purposes, both fall under the same coarse-aggregate classification in NMX-C-111-ONNCCE-2018. In practice, what changes between "grava" and "gravilla" when ordering is the nominal size requested from the supplier, not a distinct category of material.

That is why, when placing an order, it helps to avoid the generic term "gravilla" and instead specify the exact size in inches — 3/8, 3/4, 1 or 1½ — which is how manufacturers formally classify their product. That precision lowers the risk of receiving a material different from what the job needs, especially when the order is placed by phone or remotely.

What gravel size is used for each element?

There is no single mandatory table assigning a gravel size to each structural element: the maximum aggregate size is set by the mix design and the element's dimensions, particularly the clear spacing between reinforcing bars. As a general engineering criterion, the thinner or more congested with steel an element is, the smaller the maximum aggregate size should be.

Following that logic, thin elements such as slabs and floor toppings usually work with 3/8 or 3/4-inch gravel, which gives a more uniform finish. Massive elements such as foundations or column footings, with less restriction between bars, can take 1 or 1½-inch aggregate. For paving, the choice depends on the surface thickness and the project's specific design.

In every case, the final maximum size is set by the structural project or the concrete supplier's mix design, not by a general rule.

That is also why two projects with the same nominal element — say, a residential slab — can call for different gravel sizes: reinforcement spacing, finish requirements and the specific mix design all factor into the decision, so what worked on one job is not automatically the right size for the next.

What is each gravel size used for?

CEMEX Mexico labels its gravel using U.S. coarse-aggregate nomenclature (ASTM C-33), which makes it easier to compare sizes across suppliers.

GCC produces all of these sizes as crushed gravel under NMX-C-111-ONNCCE-2018. The 1-inch size, while part of GCC's production range, does not appear with its own ASTM classification in the CEMEX material reviewed for this guide.

How much does a cubic meter of gravel weigh?

Bulk density depends on whether the gravel is loose or compacted. For 3/4-inch gravel, GCC reports 1.45 to 1.50 metric tons per cubic meter loose, and 1.50 to 1.60 metric tons per cubic meter compacted. That difference matters when calculating how many truckloads a given volume requires, since the material settles as it shifts in the truck bed or is spread on site.

For sizes other than 3/4 inch, the GCC data sheet reviewed here does not report specific bulk densities; it is best to request them directly from the supplier before calculating loads.

Beyond weight, it is worth checking that the gravel arrives clean, without excess fines or organic matter mixed in, and with the continuous grading NMX-C-111-ONNCCE-2018 requires. Dirty or poorly graded aggregate can reduce concrete's final strength even when the nominal size — 3/8, 3/4, 1 or 1½ inches — is right for the element.

How does Grupo Server help?

Triturados Gramol, a Grupo Server company founded in 2003, produces gravel, sand, ballast, base and asphalt mix at two plants, one in Coahuila and one in San Luis Potosí. It is the group's company dedicated to stone aggregates, with the capacity to supply projects of different scales.

You can review Triturados Gramol's profile, browse the group's construction section or write in directly through the contact form to request a gravel quote.