5925 E 1050 S Amboy, IN. 46911 United States • (844) 395-1530 • office@gra-rock.com • Gra-Rock Redi Mix provides ready mix concrete in the northern part of the state of Indiana. They deliver concrete directly to jobsites, have guaranteed delivery, and no hidden fees. Their goal is to provide the best ready mix concrete possible combined with excellent customer service.