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Building Foundations

Building Foundations. Concrete as a Building Material. Tremendous compressive strength. Resistant to chemicals. Will not rot or be damaged by insects. Hardens even under water. Withstands extreme heat and cold. Formed into almost any shape Widely available and fairly inexpensive.

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Building Foundations

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  1. Building Foundations Concrete as a Building Material

  2. Tremendous compressive strength. Resistant to chemicals. Will not rot or be damaged by insects. Hardens even under water. Withstands extreme heat and cold. Formed into almost any shape Widely available and fairly inexpensive. Concrete As a Building Material

  3. Ingredients: cement, fine aggregate (sand), course aggregate (gravel or crushed stone), & water Hydration Inert (inactive) ingredients Active ingredients Concrete Basics

  4. Cement is manufactured substance. Consists of compounds of lime mixed with silica and alumina. Clinkers Portland Cement

  5. Type I (standard) Type II (modified) Type III (high-strength) Type IV (low heat) Type V (sulfate-resistant) 5 Basic Types of Cement

  6. Self-leveling Hydraulic Anchor Resurfacing Specialty Cements

  7. Granular material Fine Coarse Aggregates

  8. Clean & free from oil, alkali, or acid Suitable for drinking Ratio water to cement VERY important. Water

  9. Aggregates mixed thoroughly Begins when water is added. Concrete Cures! Keep it moist Hydration

  10. Improves strength 28 days Moist-Curing

  11. Air-entraining Retarding Accelerating Water-reducing Super-plasticizing Admixtures

  12. 3 methods of coloring concrete Color added to concrete Add colored layer over standard Dust powdered colorant over wet concrete Colorants

  13. Measured by the cubic yard. One cubic yard = 27 cubic feet. Working with Concrete

  14. Mixed on site Mortar hoe (hoe with holes in the blade) Ordered ready mixed. Mixing

  15. 60, 80, or 94 lb sacks. 60-lb sack = 1 cubic foot of concrete Store in dry area Using Pre-Mixed Materials

  16. Figure cement & aggregates separately Use tables Wear respirator Mixing on Site

  17. Ready-mix plants Minimum 2 cubic yards Ordered by # bags cement per cubic yard Compressive strength (psi) Using Ready-Mix

  18. Measure consistency of concrete Small sheet-metal cone of specific dimensions The greater the slump the wetter the concrete. Slump Test

  19. Poured continuously Kept fairly level Air pockets removed: vibrating, tamping, or spearing with spade Poured directly from truck Piped in from pump truck Placement

  20. Reinforced concrete Bars (rebar) Welded-wire fabric Footings, slabs & walls Reinforcing Steel

  21. Short synthetic fibers Reduce shrinkage cracking Increase resistance to impact & abrasion Fiber Reinforcement

  22. Review • List at least four useful characteristics of concrete. • What are the four basic ingredients of concrete? • What type of cement is most commonly used for concrete in general construction? • What is hydraulic cement used for? • Why is it important for coarse aggregate to be clean? • What is hydration? • Name three factors that influence the strength of concrete. • What safety precautions should be taken when mixing or placing concrete? • Name two methods for specifying the strength of ready-mix concrete. • What is the purpose of using fiber reinforcement in concrete?

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