If you’ve visited the beach recently, you might think sand is ubiquitous. But in construction uses, the perfect sand and gravel is not always an easy resource to come by. “Not all sand is equal in terms of what it can be used for,” notes Zack Sickman, coauthor of a new study to be presented on Thursday at the Geological Society of America annual meeting. He says concrete aggregate needs sand with a certain size and angularity—the kind that is considered “immature” and often, but not always, found in rivers.
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Source: Phys.org