WORLD FOR CIVIL

What is Concrete?

Brain Storming Activity 1: Concrete Survey

1. When was concrete first made?
   

   9000 BC 500 BC 100 AD 1756 1824

2. Circle the possible components of concrete.
   

   water cement gravel sand air steel rods

3. What is the purpose of cement in concrete?
4. What role does water play in producing concrete?
5. Why does concrete harden?
6. Why does concrete set (harden) slowly?
7. How can you make concrete set:
   

    faster

   
   

    slower?

8. Is concrete stronger in compression, tension, or the same in either?
9. How strong can concrete or cement be (in pounds per square inch (psi))?
   

   50,000 20,000 5000 2000

10. How long can concrete last (in years)?
    

    50,000 5000 500 50

scores: 8-10 materials science major; 5-7 concrete contractor; 2-4 concrete laborer;

0-1 home owner

Concrete Survey (Key)

1. When was concrete first made?
   9000 BC 500 BC 100 AD 1756 1824
2. Circle the possible components of concrete.
   water cement gravel sand air
3. What is the purpose of cement in concrete?
   It acts as a primary binder to join the aggregate into a solid mass.
4. What role does water play in producing concrete?
   Water is required for the cement to hydrate and solidify.
5. Why does concrete harden?
   The chemical process called cement hydration produces crystals that interlock and bind together.
6. Why does concrete set (harden) slowly?
   It takes time for the hydrated cement crystals to form
7. How can you make concrete set:
   faster? add calcium chloride or "accelerator"
   slower? add sugar or "set retarder"
8. Is concrete stronger in compression, tension, or the same in either?
   It is stronger in compression.
9. How strong can concrete or cement be (in pounds per square inch (psi))?
   50,000 20,000 5000 2000
10. How long can concrete last (in years)?
    50,000 5000 500 50

scores: 8-10 materials science major; 5-7 concrete contractor; 2-4 concrete laborer;

0-1 home owner

(Note: Correct answers are given in bold.)

Concrete- An artificial stone-like material used for various structural purposes. It is made by

mixing cement and various aggregates, such as sand, pebbles, gravel, shale, etc., with water and allowing the mixture to harden by hydration.

Here are just a few facts to help convince you that the topic of concrete deserves to become a part of your science curriculum:

• Concrete is everywhere!! Roads, sidewalks, houses, bridges, skyscrapers, pipes, dams, canals, missile silos, and nuclear waste containment. There are even concrete canoes and Frisbee competitions.
• It is strong, inexpensive, plentiful, and easy to make. But more importantly, it's versatile. It can be molded to just about any shape.
• Concrete is friendly to the environment. It's virtually all natural. It's recyclable.
• It is the most frequently used material in construction.
• Slightly more than a ton of concrete is produced every year for each person on the planet, approximately 6 billion tons per year.
• By weight, one-half to two-thirds of our infrastructures are made of concrete such as: roads, bridges, buildings, airports, sewers, canals, dams, and subways.
• Approximately 60% of our concrete highways need repair and 40% of our concrete highway bridges are structurally deficient or functionally obsolete.
• Large cities lose up to 30% of their daily water supply due to leaks in concrete water pipes.
• It has been estimated that the necessary repairs and improvements to our infrastructures will cost $3.3 trillion over a nineteen-year period. $1 trillion of that is needed for repairing the nation's concrete.
• Cement has been around for at least 12 million years and has played an important role in history.

Brainstorming Activity 2: Why is Concrete Important?

Objective: Students will create a list of the importance of concrete and explain how it affects their lives.

Procedure:

1. "Why concrete is important?" In a large group students will create a list of the importance of studying concrete.

2. Upon completion of their list, students will develop acronyms for concrete based on their list of concrete's importance. (See example below.)

3. Students will discuss the implications that would occur if we could no longer make concrete. (i.e. increasing levels of CO₂ production or federal regulations)

Brainstorming Activity 3: Applications of Concrete

Objective: Students will create a list of the past, present, and future applications of concrete and how these applications affect their lives and lifestyles.

Procedure:

In small groups, the students will list applications for concrete:

1. In the past:
   Students will create a list of past applications for concrete that has influenced their lives and/or lifestyles.
2. Currently:
   Students will describe common applications of concrete that they encounter daily. Label these as present applications of concrete.
3. In the future:
   Students will create a list of future applications of concrete by predicting how concrete will affect their lives in the future.
4. Students will present their lists to the class in the form of a collage or a mobile displaying the correlation between their lives and lifestyles with the applications of concrete throughout their lives.

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APPLICATIONS OF CONCRETE

Past, Present, and Future

roads	sidewalks	houses
bricks/blocks	bridges	walls
beams	foundations	floors
sewer pipes	water mains	computer chip backing **
canals	missile silos	containment of nuclear waste
dams	churches	automobile brake lining **
caskets	monuments	solidification of hazardous wastes
tombs	indoor furniture	garden ornaments
swimming pools	airport runways	sailing boats
canoes	barges	subways
tunnels	parking garages	patio bricks
holding tanks	cement "overshoes"	sculptures
flower pots & planters	chimneys	mantels
ballast	bath tubs	grave vaults
bank vaults	basements	lamp posts
telephone poles	electric light poles	Frisbees
headstones	steps	fence posts
business/credit cards **	fertilizer	bone replacement **
insulating tiles/bricks	corn silos	park benches
parking stones	roof tiles	water troughs
water tanks	curb & gutters	nuclear reactor containment structures
artificial rocks	office buildings	parking lots
railroad ties	airports	monorails
picnic tables	swimming pools	break waters
wharves & piers	bird baths	barbecue pits
stadium seats	fountains	lunar bases **

** Denotes future applications.