Concrete bridge

High school (ages 12+)
Transportation

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Date:

Step 1 · Read the article

Open the article and read it at the level above. Then answer the questions below in your own words.

https://smallwhale.org/articles/concrete-bridge

Write what each word means, using the article.

Do not copy the article. Write two things you learned, the way you would explain them to a friend.

Answers below are taken from the article’s stored facts, so they match what the student read.

1. What is the compressive strength?Typically 20-50 MPa, significantly higher for specialized mixes
2. What is the tensile strength?Low, requiring steel reinforcement (rebar or tendons) for tensile loads
3. What makes concrete bridges super strong?Concrete is very strong when it squeezes, so it can hold heavy loads. But it is weak when it pulls apart, so engineers add steel bars inside to keep it from cracking.
4. Why do engineers put steel bars inside concrete bridges?Steel bars are very good at pulling, so they help the bridge resist tension and keep the concrete from breaking.

Portland Cement: A key binder in concrete, produced by heating limestone and clay, then grinding.
Alkali-Aggregate Reaction (AAR): A chemical reaction between cement alkali and certain aggregates that can cause concrete expansion and cracking.
Prestressed Concrete: Concrete in which internal stresses are introduced to counteract external loads, typically by tensioning steel tendons.
Lifecycle Cost Analysis: An economic evaluation that considers all costs associated with an asset over its entire lifespan.