Aggregate, gravel ja macadam tähendavad inglise keeles sarnast materjali.
Aggregate (killustik) on mäenduses killustik, mis on saadud kivimimassiivi raimamise ja purustamise teel. Purustada võib ka kruusa (gravel) ja saada kruuskillustikku. Kui killustikust valmistatakse teekattekillustik, e. sobiva tükisuurusega killustik, siis nimetavad tee-ehitajad seda inglise keeles macadam.
macadam 1824, named for inventor, Scot. civil engineer John L. McAdam (1756-1836), who developed a method of leveling roads and paving them with gravel and outlined the process in his pamphlet "Remarks on the Present System of Road-Making" (1822). Originally, road material consisting of a solid mass of stones of nearly uniform size laid down in layers; he did not approve of the use of binding materials or rollers. The idea of mixing tar with the gravel began 1880s. Verb macadamize is first recorded 1826.
