Concrete Fundamentals and Foundation Materials
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Questions and Answers

What is the minimum compressive strength required for interior concrete slabs according to specified guidelines?

  • 10 MPA
  • 32 MPA
  • 20 MPA (correct)
  • 15 MPA

    • Which materials make up the typical concrete mix in the 10-20-30-40 Rule?

  • 10% water, 40% cement, 30% sand, 20% gravel
  • 20% cement, 30% sand, 40% gravel, 10% air
  • 10% cement, 20% air and water, 30% sand, 40% gravel (correct)
  • 30% cement, 40% sand, 20% water, 10% gravel

    • What should be done to prevent segregation of concrete materials?

  • Use a mix with lower water content
  • Pour concrete from at least 10’ height
  • Place concrete in forms (correct)
  • Vibrate the concrete thoroughly before placement

    • What is the primary purpose of using steel trowels in concrete finishing?

    <p>To provide smooth concrete finishes</p> Signup and view all the answers

    What is the allowed maximum height from which concrete can fall into place to avoid material segregation?

    <p>8’ (2.4m)</p> Signup and view all the answers

    Which of the following is not a component of concrete?

    <p>Steel fibers</p> Signup and view all the answers

    The 10-20-30-40 Rule indicates percentages of materials in a concrete mix. What is the percentage of air in this rule?

    <p>20%</p> Signup and view all the answers

    What is the purpose of having specific divisions in construction specifications?

    <p>To categorize different types of work and materials</p> Signup and view all the answers

    What is the minimum thickness required for basement concrete floor slabs?

    <p>3 inches</p> Signup and view all the answers

    What is the purpose of control joints in foundation walls?

    <p>To relieve stress from shrinkage or expansion</p> Signup and view all the answers

    What is the maximum spacing allowed between anchor bolts in a foundation wall?

    <p>7 feet 10 inches</p> Signup and view all the answers

    How far should anchor bolts project out of the concrete to secure a sill plate?

    <p>2 inches</p> Signup and view all the answers

    What is the purpose of premolded expansion joints in concrete slabs?

    <p>To allow for thermal expansion and contraction</p> Signup and view all the answers

    What is the required minimum vapor barrier thickness under a basement floor slab?

    <p>6 mil</p> Signup and view all the answers

    What materials are typically used in pre-manufactured modular foundations?

    <p>Insulated precast concrete and steel studs</p> Signup and view all the answers

    What is the minimum distance from the end of a plate to an anchor bolt?

    <p>4 inches</p> Signup and view all the answers

    What causes the movement that control joints in foundation walls are designed to relieve?

    <p>Concrete curing shrinkage or expansion</p> Signup and view all the answers

    What is the main benefit of using modular foundations in construction?

    <p>Increased accuracy and reduction of construction time</p> Signup and view all the answers

    What does EWP stand for in the context of wood products?

    <p>Engineered Wood Products</p> Signup and view all the answers

    Which of the following materials are specifically mentioned as part of EWP manufacturing?

    <p>Wood strands</p> Signup and view all the answers

    What role do adhesives play in the production of EWP?

    <p>They are a binding agent used to combine wood materials.</p> Signup and view all the answers

    Which of the following best describes the process of manufacturing EWP?

    <p>Binding or fixing wood materials together.</p> Signup and view all the answers

    What type of wood products does the term 'derivative wood products' refer to?

    <p>Products manufactured from wood as the primary component.</p> Signup and view all the answers

    Which of the following is NOT a method used in the production of EWP?

    <p>Thermal peeling</p> Signup and view all the answers

    Which characteristic is most commonly associated with EWP compared to natural wood?

    <p>Increased dimensional stability.</p> Signup and view all the answers

    What can be inferred about the market for EWP based on modern construction trends?

    <p>It is growing because of demands for sustainable materials.</p> Signup and view all the answers

    What is a primary advantage of using EWP over traditional solid wood?

    <p>Uniformity in size and strength characteristics.</p> Signup and view all the answers

    What kind of products are typically categorized under EWP?

    <p>Veneer sheets and plywood.</p> Signup and view all the answers

    What is true about laterally supported foundation walls?

    <p>They have a floor system secured to the top.</p> Signup and view all the answers

    Which material is typically NOT a common foundation material?

    <p>Steel mesh</p> Signup and view all the answers

    What does ICF stand for in foundation construction?

    <p>Insulated Concrete Forms</p> Signup and view all the answers

    The thickness of foundation walls typically ranges from:

    <p>8” to 12”</p> Signup and view all the answers

    How long must regular formwork remain in place to be effective?

    <p>3 days</p> Signup and view all the answers

    What is an essential characteristic of the formwork used in cast-in-place concrete?

    <p>It must withstand the pressure of fresh concrete.</p> Signup and view all the answers

    Why are box-outs used in insulated concrete forms?

    <p>To control the placement of concrete.</p> Signup and view all the answers

    What is crucial to perform while placing cast-in-place concrete?

    <p>Vibrating the concrete to remove air pockets.</p> Signup and view all the answers

    What does ICF provide that standard formwork does not?

    <p>Heat retention and insulation.</p> Signup and view all the answers

    What is a potential issue with unsupervised cast-in-place concrete pouring?

    <p>Improper mixing resulting in inconsistency.</p> Signup and view all the answers

    What is the purpose of joist hangers in floor framing?

    <p>To hold wood joists in place for a thinner floor structure</p> Signup and view all the answers

    When referring to ceiling finish furring, which of the following is true?

    <p>It refers to the same process as strapping.</p> Signup and view all the answers

    What is the maximum allowable cantilever length for a floor joist using '2x10'?

    <p>24 inches (610 mm)</p> Signup and view all the answers

    Which statement about joist positioning when a bow is present is correct?

    <p>The crown of the joist should be placed on top.</p> Signup and view all the answers

    What type of materials are typically used for subfloors?

    <p>Plywood or OSB</p> Signup and view all the answers

    Study Notes

    Concrete Fundamentals

    • Concrete is a common material used for foundations, footings, slabs, columns and piers.
    • Compressive strength is measured in Mega Pascals (MPa).
    • Concrete is composed of cement, sand, aggregates and water.
    • The typical concrete mix is made up of roughly 10% cement, 20% air and water, 30% sand, and 40% gravel.
    • This is called the 10-20-30-40 rule.
    • Concrete should be placed in forms.
    • Concrete should not fall in place over a height of 8’ (2.4m).  
    • Concrete should be spread and then leveled.
    • Steel trowels create smooth finishes.
    • Aluminum-magnesium trowels are used for textured finishes.

    Common Foundation Materials

    • There are four common foundation materials:
      • Cast-in-place concrete
      • Concrete block (CMU)
      • Preserved and treated wood
      • Insulated Concrete Forms (ICF)
    • The thickness of cast-in-place concrete, concrete block and ICF systems depends on the depth of the wall below grade.

    Foundation Walls

    • Foundation walls are typically 8" to 12" thick.
    • There are two types of foundation walls:
      • Laterally Supported
      • Laterally Unsupported
    • A laterally supported foundation wall has a floor system secured to the top of the foundation wall.
    • A laterally unsupported foundation wall does not have a floor system secured to the top of the foundation wall.  

    Formwork

    • Formwork holds concrete in place until it cures.
    • Formwork can be temporary or permanent.
    • Most forms are made of steel or plywood.
    • Metal tie bars keep the two sides of the formwork from separating.
    • Formwork should be tight, well braced and strong enough to withstand the concrete pressure.
    • Formwork should remain in place for at least 3 days.

    Insulated Concrete Forms

    • Insulated Concrete Forms (ICF) result in cast-in-place concrete walls that are sandwiched between two layers of insulation material.
    • ICF's remain in place permanently providing both formwork and insulation for the walls.
    • Box-outs are placed between the forms at door, window and beam locations to prevent concrete from being placed in these locations.

    Cast-in-Place Concrete Foundation Walls 

    • Cast-in-place concrete should be vibrated during placement to remove air pockets.
    • Concrete should be placed as one continuous pour, especially when the wall is being placed in a single pour.

    Pre-Manufactured (Modular) Foundations

    • Modular foundations can speed up construction time.
    • They are accurate as they are pre-manufactured at a factory.

    Basement Concrete Floor Slabs

    • Basement concrete floor slabs are typically poured in place after the roof and rough-in plumbing is completed.
    • Minimum thickness of 3" (75mm) concrete on 6 mil polyethylene vapor barrier on a minimum of 4" (100mm) granular fill is required.
    • Concrete slabs, interior and exterior poured against other material should always have a pre-molded expansion joint.

    Foundation Wall Details

    • Anchor bolts should be set in the concrete pour before it hardens.
    • Anchor bolts should project out of the concrete a minimum of 2" (50mm) so a sill plate can be secured with a nut and washer.
    • The maximum distance between anchor bolts is 7'-10" (2.4m).  
    • The maximum distance from the end of a plate to the anchor bolt is 12" (305mm) and the minimum is 4" (100mm).

    Control Joints in Foundation Walls

    • Control joints are used to relieve stress caused by shrinking, expanding and contracting.
    • This movement is the result of moisture absorption and expulsion.

    Engineered Wood Products

    • Engineered wood products (EWP) are manufactured composite materials using strands, particles, fibers, or veneers of wood.

    Floor Framing - Joists

    • Joists can be supported in several ways
      • framed into masonry or concrete walls
      • on ledger strips attached to wood beams
      • on top of wood beams
    • Joists supported by masonry or concrete walls must be treated to prevent decay.
    • Any joist having a slight bow edgewise should be placed with the crown on top.
    • Joist hangers are designed to hold wood joists in place when a thinner floor structure is desired.
    • Bridging, strapping and blocking are used to strengthen and prevent joists from twisting.  
    • Bridging and strapping should not be at a distance greater than 6'-11" (2.108m) from joist support.
    • Ceiling finish furring is the same as strapping but is referred to as furring when it is used for the attachment of ceiling finishes.

    Joist Framing at Openings

    • Interrupted joists must be headed off to transfer their loads to adjacent joists.
    • If the header spans more than 4 feet, it must be doubled and the loads transferred to double trimmer joists.

    Floor Framing at Cantilevers

    • A cantilever is a projecting structure that is only supported at one end.  
    • A floor joist projecting beyond a load bearing wall to provide support for a bay window or additional floor space can cantilever up to:
      • 16" (406mm) using '2x8' (38x184)
      • 24" (610mm) using '2x10' (38x235)

    Floor Joist Materials

    • Typical dimensional lumber for joists:
      • '2x6'
      • '2x8'
      • '2x10'
      • '2x12'
    • Engineered Wood Products:
      • Wood I-Joists
      • Open Web Joists

    Subfloors

    • Subfloors are typically made of plywood or oriented strand board (OSB).  
    • Typical sheet size is 4'-0" x 8'-0".
    • Sheets should be installed at right angles to the floor joists with the end joints staggered.

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    Week 6 Midterm Exam Review PDF

    Description

    This quiz covers essential concepts related to concrete, including its composition, typical mixes, and common foundation materials. Learn about the properties of concrete, proper placement techniques, and the different types of foundation materials used in construction. Test your knowledge on these critical components of civil engineering.

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