Roman concrete

High school (ages 12+)
Science & Technology

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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/roman-concrete

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 material composition?Hydraulic-setting cement (lime-based) mixed with aggregate, often enhanced with pozzolanic ash
2. What is the period of widespread use?From approximately 150 BC onwards
3. What is Roman concrete and why was it special?Roman concrete, called opus caementicium, could harden in water, letting Romans build underwater structures like piers and harbors.
4. How did Roman concrete stay strong for thousands of years?It used lime mixed with volcanic ash that reacted with water to make a very strong, water‑resistant compound that stopped tiny cracks from spreading.

Opus caementicium: The Latin term for Roman concrete, a foundational material in ancient Roman construction.
Hydraulic cement: A cement that hardens and gains strength through a chemical reaction with water, allowing underwater curing.
Pozzolanic reaction: A chemical reaction between pozzolana (like volcanic ash) and calcium hydroxide (lime) in the presence of water to form cementitious compounds.
Lime clasts: Small fragments of lime within a concrete matrix that can react with water to facilitate self-healing.