"20 mm all in aggregate" refers to a type of construction material that includes a mixture of coarse particles, typically used in concrete or other building applications. The "20 mm" indicates the maximum size of the aggregate particles, meaning none of the individual pieces in the mix are larger than 20 millimeters in diameter. "All in" signifies that the aggregate is a combined mixture of different particle sizes, without screening or separation, including both fine and coarse aggregates. This type of material ensures a consistent and stable mixture that is often used for creating a solid foundation or for mixing with cement to make concrete.
