перевожу текст про насосы высокого давления и гидроструйное оборудование. В таблице "области применения" есть строительная промышленность. В ней перечисляется:

Exposing aggregate (retarded). Asphalt distributors, mixers, tar cookers and pavers.
Asphalt, dirt, concrete, mortar, tar, grease, mastic and clay on vehicles, mixer trucks and machinery.
Latence for canals, lifts, dams and runways prior to pours (no retarders). Exposing aggregate (unretarded) and concrete cutting.

Exposing aggregate я так понимаю оголение щебеночной основы. А причем тут тогда reretarded/unretarded? С добавлением/без добавления замедлителя схватывания??

Заранее спасибо.

Is it practical to treat formwork so that surface concrete will not harden?
Yes, there are commercial products--glucose-base or other materials--which can be applied to the interior surfaces of forms that will kill the normal set of the concrete on the surface. The depth of the kill depends on the thickness of the coating, and some skill is required to obtain the precise effect desired. After the form has been stripped, the unhydrated cement can be brushed or waterblasted away to expose the surface aggregates.

Aggregate - наполнитель (в бетоне)
https://www.google.ru/search?q=exposed+aggregate+concrete&newwindow=1&source=lnms&tbm=isch&sa=X&ei=GPz0UqPsIcfP4QTAjYDICw&ved=0CAcQ_AUoAQ&biw=1149&bih=621