Such as sand not clean (mud high content), sand the fineness modulus too high or too low, also can make the strength of concrete is reduced, and the water increased.

如砂石不干净(泥含量较大)、砂的细度模数过高或过低等，也会使混凝土强度降低、泌水性增加。

youdao

The material was sand of every degree of fineness and of various rich colors, commonly mixed with a little clay.

那材料是各种粗细不同的细沙，颜色也各不相同，往往还要包含一些泥土。

youdao

Two days earlier, it had scooped some sand from a drift, sieved it to a fineness of less than a hundred and fifty microns, and dropped a portion half the size of a baby aspirin into a funnel on its back.

NEWYORKER: The Martian Chroniclers