Where is Concrete Aggregate found?
Artificial aggregate (likely crushed stone or gravel)
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Open the appConcrete Aggregate occurs in specific geological environments. Knowing where to look, and in what kind of rock, is the difference between going home empty-handed and finding a great specimen.
Where to find Concrete Aggregate
Quarries
Locations where bedrock is extracted and crushed to produce aggregate. Found globally wherever suitable rock formations exist.
Gravel Pits
Deposits of naturally occurring sand and gravel, often found in river valleys, floodplains, glacial outwash plains, and ancient beach ridges.
Construction Sites
Aggregates are delivered to construction sites for immediate use in concrete, asphalt, or other civil engineering projects.
Collecting tips
- Source Rock Identification. To understand the aggregate, identify the dominant rock types present. This requires basic knowledge of common igneous, sedimentary, and metamorphic rocks.
- Particle Shape and Texture. Observe the shape (angularity) and surface texture (roughness) of the particles. Crushed aggregates are typically angular with rough surfaces, while natural gravels are more rounded and smoother due to abrasion.
- Size Distribution. Note the range of particle sizes. Aggregates are typically graded into specific size fractions for different concrete applications.
- Presence of Deleterious Materials. Look for any undesirable components such as clay lumps, organic matter, soft particles, or reactive minerals (e.g., chert, opal, volcanic glass) that could negatively impact concrete performance. These are often identified through laboratory testing.
Quick Check
- Color:
- Variable (grey, black, brown, white, red, mixed)
- Luster:
- Dull to vitreous
- Streak:
- Not applicable (aggregate is a mixture of rock fragments)
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