Construction Technology Concrete 101

What are the four primary ingredients of concrete?

• Water, sand, gravel, and cement

• Water, clay, limestone, and cement

• Sand, gravel, lime, and water

• Cement, aggregate, water, and steel

Which statement accurately describes the relationship between cement and concrete?

• Cement is a type of concrete.

• Concrete is an ingredient in cement.

• Cement is a binding ingredient used to make concrete.

• They are interchangeable terms for the same material.

How does Portland cement cure to become solid?

• Through drying and evaporation of water.

• Through a chemical reaction called hydration.

• By being exposed to air.

• By being heated in a kiln.

What is the primary purpose of using aggregates like sand and gravel in concrete?

• To make the concrete more flexible.

• To increase strength and reduce shrinkage.

• To make the concrete lighter.

• To change the color of the concrete.

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What is the primary trade-off when increasing the water content in a concrete mix?

• Increased strength for decreased workability.

• Increased workability for decreased strength.

• Increased density for decreased curing time.

• Increased curing time for decreased density.

What is a characteristic of concrete mixed with just enough water to wet it, making it extremely dry?

• It flows easily into forms and has high workability.

• It is used in applications requiring high flexibility.

• It is difficult to flow but can be compacted into place.

• It cures very quickly, reducing construction time.

What was the approximate average compressive strength of the concrete samples mixed with the most water?

• 3000 PSI (20 MPa)

• 2200 PSI (15 MPa)

• 1600 PSI (11 MPa)

• 700 PSI (5 MPa)

Which of the following concrete samples demonstrated the highest compressive strength?

• Samples with the most water.

• Samples with water in the recommended high range.

• Samples with water in the recommended low range.

• Samples with the least water.