GRAVILLA Gravel of less than 2 cms. In diameter, natural or manmade, used in unpaved roads, concrete mix, tenis courts, running fields and so on. Some synonyms, words or similar expressions can be ripio, grava, gravilla, de tierra, gravel
Used in US as well
"Hay que volver a echar gravilla a la cancha. There is a need to regravel the court."