A Take-home Project
Objective: Students will develop an understanding of concrete as a construction material. A concrete product will be designed and constructed.
Concrete is everywhere. Take a moment and think about all the concrete encounters you have had in the last 24 hours. All of these applications of concrete are created from a material that is a mixture formed from the chemical reaction of cement and water (hydration) with added aggregate. It important to distinguish between cement and concrete as they are not the same. Cement is used to make concrete.
Water is a key reactant. Water and cement initially form a cement paste that begins to react through the chemical process of hydration. In the hydration of cement, chemical changes occur slowly, eventually creating new crystalline products, heat evolution, and other measurable signs. The hydration process hardens (sets) the paste which binds the aggregate particles together.
The aggregate is the solid particles that are bound together by the cement paste to create the synthetic rock known as concrete. Aggregates can be both fine, such as sand, and/or coarse, such as gravel. The relative amounts of each type and the sizes of each type of aggregate determines the physical properties of the concrete.
Time: 1 Class period for each object made. (45 min.)
Materials and Supplies for groups of 2-3:
Notes for Teacher: