3.Construction Materials
See Guys ! This one is easy ! Let’s go see! J
In this activity, you will learn about different materials used in transportation, such as wood, metals, concrete, pavements and composite materials. You will prepare and test some of these materials.
Background:
Roads have been used for transportation for over 3,000 years. They are made of different materials such as wood, metals asphalts, concrete and composites. Before using these materials in roads, building and bridges, we must test them to make sure they are strong enough to take the load.
Pavements are often tested using compression, or "pressing" the material under weight. For example, compressive forces exist when you walk on concrete. Tensile stresses occur when you pull on a sample. The cable that supports the load of a crane is an example of tensile stresses. Concrete has very good compressive properties, but very poor tensile strength unless steel reinforcements are added,
Materials such as sand, stone, and gravel, are added to cement and asphalt to increase volume and strength. They are known as aggregates. Newer manmade materials have been successfully used to increase strength, such as admixtures.
1. Mix concrete to make small specimens. Different mixtures will be made. Suggested recipe for concrete is 3 parts aggregate, 2 parts cement, and 1 part water. Any combination of aggregate or none at all may be used. The exact amount of each component to be used is up to you.
2. After curing for 2-3 days, test the specimens under different loading conditions until failure.
3. Load the plates in tension compression and flexure
4.
Review
different slides of different concrete structures: tall buildings, bridges,
dams and historical structures
5. Compare different materials and list the advantages and disadvantages.
6. Answer questions on worksheets
7. Compare the strength of each concrete mix and report the results.
8. Strength = load (weight)/area (square inches)
