When you think about quality aggregates, you probably imagine strong, clean stone or durable sand. But not every piece of aggregate is solid gold. Sometimes, you get clay lumps or weak, crumbly particles mixed in.

In concrete mix design, sand might not get the same attention as cement or gravel — but it quietly influences almost everything. From water demand to workability to strength, fine aggregate properties matter. A lot.

When we think about concrete mix design, it’s easy to jump straight to water-cement ratio, slump, and strength. But one number quietly influences all of it: specific gravity. Specific gravity tells us how heavy or