Some Common sizes:
MD #5 = 1 - 1 1/2"
MD #8 = 3/8 - 1/2"
#10 Stone Dust Fines/dust with up to 1/4"
#57 Stone 3/4 to 1-1/4"
MD #2 / AASHTO #3 Stone: 2"
CR-6 up to 1 1/2″
CR-8 - 1” minus crusher run. Commonly referred to as "Site pack" or "Quarry Process Stone" or "Road Base"
See Aggregrate Gradation Chart
Source: Project Planning and Estimating Resources | The Stone Store

Terms:
ASTM International, formerly known as American Society for Testing and Materials, is an international standards organization that develops and publishes voluntary consensus technical standards for a wide range of materials, products, systems, and services. See Wikipedia and www.astm.org.

CR - Crushed Rock ?

California bearing ratio (CBR) test is a penetration test for evaluation of the mechanical behavior of road base and subbase course layers.

Graded aggregate base (GAB)

MD - A grading system for aggregates e.g. MD #1 = 3 1/2 - 4"; MD #5 = 1 - 1 1/2"; MD #8 = 3/8 - 1/2"

MD: Micro deval test Maryland

MDOT SHA - Maryland Department of Transportation State Highway Administration

Links:
Aggregate Sizing Explained
Project Planning and Estimating Resources | The Stone Store
Crushed Stone Examples | paxcos.com
Development Of Design Guidelines For Proper Selection Of Graded Aggregate Base In Maryland State Highways

last updated 10 Oct 2018