Midterm Concrete Flashcards
Which of the following techniques have proven successful in providing specified strengths in 4 hours of less? Select all that apply.
High Portland cement contents
Accelerating admixtures
Type III Portland cement
Air- en-training admixtures are primarily used to stabilize tiny air bubbles in concrete
True
Prebid and pre- construction conferences should be held to identify.
Lines of communication
Responsibilities
Discuss the contract requirements
“For all linear systems, the net response at a given place and time caused by two or more stimuli is
the sum of the responses which would have been caused by each stimulus individually”, is the:
Superposition Principle
Which deep foundation type is not suitable for installation in wet and/or loose soils?
Drilled piers
A hydraulic cement creates a chemical reaction when it comes in contact with water (hydration) but will not
cure under water.
False
(fill the blank) are the critical elements for a successful project regarding clearly delineated and
efficient office procedures for the administration of design, document control, checking of shop or
placing drawings, and processing design changes
Quality Insurance and Quality Control
Expansion joints are used at points of restraint, Expansion joints are used at points of restraint, including the junction between the elements of a structure. For example, they separate walls or columns from floors.
True
As part of jobsite preparation, before concrete is poured, it is important to be aware of any potential
increased pressure on the forms. Which of the following factors increase pressure on forms?
Increase in lift heights
Long term compressive strength of concrete using Type III Portland cement is higher than with
Type I Portland cement (general purpose).
False
Formwork accounts for 35 to 60% of the construction cost for concrete framed buildings.
True
Which of the following factors influence reinforcement development strength? I – Rebar spacing, II –
Concrete weight, III – Concrete cover, IV – Heat of hydration V – Rebar coating
I, II, III & V only
The temperature rise due to heat of hydration in concrete utilizing Type I Portland cement typically
levels off at approximately.
Between 3 and 7 days
Given the following design conditions for a Wall form system:
Concrete Mix = Type III cement without retarder, Concrete Unit Weight (w) = 150 pcf
Wall height (h) = 10 Feet high, Rate of Pour (R) = 8 Feet per hour,
Concrete Temperature (T) = 80 Degrees Fahrenheit,Wall Thickness = 12 inches
What is the maximum design pressure on the wall in pounds per square foot (psf)?
(1) (1) [150+43,400/80+2800(8/80)] =
972. 5
In regards to formwork, the lateral pressure on vertical forms is proportional to density and depth.
True
Given the following design conditions for a column form system:
Concrete Mix = Type III cement with retarder,Concrete Unit Weight (w) = 150 pcf
Column height (h) = 10, Feet highRate of Pour (R) = 8, Feet per hourConcrete Temperature (T) =
80 Degrees Fahrenheit
What is the maximum design pressure on the wall in pounds per square foot (psf)?
(1) (1.2) [ 150 + 9,000(8/80)] =
1260
Typically, the Design Professional should review and approve the concrete mixture proportions (mix
design) and submittals concerning materials, procedures, and testing data.
True
When installing concrete in extreme weather conditions, different techniques are used to help mitigate the
effect of temperature. Which of the following are typical cold weather concrete techniques? Select all that
apply.
Leave forms in place
Engineers apply factors to selected load cases to create Load Combinations used for design:
True
Contraction joints are where concrete placements stop and start.
False