• How Much Highway? student handout
• Access to the Internet, and to the Minerals Education Coalition website (MineralsEducationCoalition.org/esw) 
• Access to color printer
• Straight edge/ruler
• Protractor
• Paper and pencil

Aggregates (stone, sand, and gravel) are among the most mined materials in the world. Mining engineers plan and manage aggregate quarries. A coarse aggregate—such as natural gravel or crushed stone—is used along with a fine aggregate (such as sand), Portland cement, and water to produce Portland cement concrete, a common cement used worldwide.

Determining the size of conical-shaped stockpiles of coarse aggregate is important in ensuring that an adequate amount of coarse aggregate is available to be mixed for the amount of concrete needed for a specific purpose, such as road paving. A basic mix recipe of one part Portland cement to two parts sand to three parts gravel (i.e., 1: 2: 3) has been used historically for many applications in construction. Aggregate for concrete is often mined locally due to the expense of transporting heavy aggregates.

Student Challenge

Students apply aspects of ratio and proportion and geometry to calculate how much highway pavement can be made from Portland Cement concrete.

Success Criteria

• Explain the meaning of natural angle of repose of earth materials.
• Show how to use stockpile measurements to calculate the volume of a conical shaped stockpile.
• Describe the importance of aggregates and their uses in daily life.
• Calculate how much Portland Cement concrete highway pavement may be constructed from a stockpile volume of coarse aggregate, in this case natural gravel.
• Explain how Portland Cement concrete is made and placed.
• Demonstrate an understanding of the meaning of and use of technical terms such as natural angle of repose, coarse aggregate, fine aggregate, fines, Portland Cement, Portland Cement concrete and mix design.