The employee is occasionallyrequired to sit, balance, reach, crawl, kneel, crouch, bend, push, pull and climb stairs, ladders, inclined walkways and access elevated platforms. As a major supplier of aggregates in Nebraska since 1921, Central Sand and Gravel Company, A CRH Company, has a long history as a mainstay of construction and development projects throughout the state – even supplying aggregates for one of Nebraska’s very first concrete paving projects.