• Shuffle
    Toggle On
    Toggle Off
  • Alphabetize
    Toggle On
    Toggle Off
  • Front First
    Toggle On
    Toggle Off
  • Both Sides
    Toggle On
    Toggle Off
  • Read
    Toggle On
    Toggle Off

Card Range To Study



Play button


Play button




Click to flip

Use LEFT and RIGHT arrow keys to navigate between flashcards;

Use UP and DOWN arrow keys to flip the card;

H to show hint;

A reads text to speech;

68 Cards in this Set

  • Front
  • Back

What is durability? (In terms of material life)

ability to last for the servce life without unacceptable performance related to materials

Durability of materials contributes to the environment by:

conserving natural resources, reducing green house gases

What is the number one cause of concrete deterioration?

Corrosion of rebar in concrete

What is carbonation induced corrosion?

Atmospheric CO2 diffuses the concrete, reacting with Ca(OH)2, lowering the pH

Why does entrained air limit freeze-thaw damage?

lets water expand into entrained air voids and/or eliminating saturation with water

What is acid attack of concrete?

corrosion through H2SO4 bacteria in sewage. H2S emission

What is sulphate attack of concrete?

sulphur from groundwater reacts with aluminate phases- creates softening, expansion and cracking

What is Akali Aggregate Reaction (AAR)?

Akali aggregates exposed to atmosphere reacts to create spalling and cracks

What are general solutions to improve durability in concrete?

low w/c by using super-P



proper placement and curing practices

Name five types of targeted solutions to a specific problem:

Air entrainment (freeze thaw)

cement/aggregate selection (AAR)

Shrinkage reduction (crack reduction)

absorption reduction (surface properties)

coatings, cathodic protection (steel corrosion)

What are the design criteria for proportioning concrete mixtures?

strength, durability, workability, sustainability, economy, appearance

What are the exposure classes of CSA A23.1

C1- strucural concrete with or without freeze thaw conditons; exposed to chlorides

C2- non-structural, freeze thaw, exposed to chloride

F1- freeze thaw, saturated, no chloride

F2- freeze thaw, unsaturated, no chloride

What are the three phases of concrete?

aggregate, cement paste, ITZ

Why is concrete weaker than the aggregate and cement paste separately?

ITZ is in concrete. creates weak points for cracks to propogate

Why is load control testing less effective than displacement control?

load control only gets a portion of a displacement curve (stops at failure), as displacement control goes past failure load.

What are main differences between ITZ and bulk paste?


- less hydrated cement

- higher porosity

- less CSH

- more ettringite

Explain the weakness of the ITZ.

the mortar and aggregate have different responses

Describe the relationship between strength and W/C

as w/c increases, strength decreases

Describe the relationship between permeability and W/C

as w/c increases, coefficient of permeability exponentially increases

What is mortar volume fraction?

(Volume of cement, water, fine aggregate, and sometimes air)/ Total volume (1m3)

What are the main primary strength producing minerals of clinker?

C3S and C2S

What are the hydration reactions of C3S and C2S?

Hydrates with water to create CSH

What are the elements in cement?

Oxygen, Si, Ca, Al, Fe

What is the nature of CSH?

"glue" that provides strength (from VDW forces)

- poorly crystallized, porous

What does Calcium Hydroxide provide to concrete

- large crystal structure, however has a low strength

- forms around ITZ

reacts with pozzolanic SCM to form more CSH

Why is gypsum added to cement?

to avoid flash set (stiffening and loss of workability)

Why is limestone added to cement?

reduce greenhouse gases

What does fineness of cement mean in regards to creating concrete?

increasing fineness, increase rate of reaction

give off more heat earlier in hydration

How is HE concrete achieved?

increasing fineness

increasing C3S

How is HS cement achieved?

reduced C3A content

blend SCM

What is blended cement?

mixture of portland cement and:

fly ash



natural pozzolan


What are pozzolans?

Common name for several SCMs containing amorphous silica

What is slag?

waste slag from iron ore

- increases durability

-decreases permeability

-slow reaction

What is fly ash?

waste ash from burning of coal

(reacts with Ca(OH)2 to produce additional CSH

- increases durability

-decreases permeability-slow reaction

** used to reduce heat of hydration in large structures such as dams, raft foundations, and bridges

What does air entrainer do?

- Improves workability

- Lowers comp. strength

- Provide durability in terms of freeze thaw

Whatis a water reducer? How does it work?

- Absorbs on surface of cement particle (negativecharge)

- Lets particles slide easier

- To get to a certain slump

Whatis superplasticizer?

- High range water reducer

- Can create flowing concrete without segregation

What is retarder?

- Delay setting or hardening rate

- For long delivery times

Whatis accelerator?

- Early hydration (setting)

- Early strength gain

What is corrosion inhibitor? How does it work?

- Delays time to corrode steel reinforcement- Increases chloride threshold of steel surface

How does shrinkage-reducing admixtures work?

- Reducing the surface tension of the watermeniscus, reducing internal attractive forces with the pores

Howdoes waterproofing admixtures work?

- Reduces permeability

- Reduces absorption

How does central plant mixing work?

- Ingredients mixed in central mixer and wetconcrete added into truck

Howdoes transit plant mixing work?

Ingredientsadded separately in truck and mixed with truck’s drum

What are three different types of curing methods?

- Early protection (misting, evaporation retarder,wind screens

- Continuous moist curing (wet burlap andsprinkler, white fabric for reflection of sun)

- Curing compounds (polymer film on surface,reflects sunlight)

List 5 factors that affect workability?

- Water content

- Aggregate characteristics

- Air temp

- Concrete temp

- Fineness of cementing materials

What are advantages of reducing water content?

- Increase strength

- Lower permeability

- Increased durability

- Better bond between concrete and rebar - - Reduced cracking

What are the three different models to predict elastic modulus in concrete?


Parallel model - predicts high upper bound solution

Series model - predicts lower bound solution

Describe the stress strain curves of aggregate, cement paste, and concrete

Aggregate curve very steep (high stress, low strain)

Cement paste has much higher strain for a given stress (depends on porosity)

Concrete curve is in between (much more non-linear)

Typical E values for aggregate, concrete, and paste?

45-85 GPa for Aggregate

30-50 GPa for concrete

10GPa for paste

What are capillary pores?

a residue of originally filled water spaces in fresh concrete (significantly reduce strength)

concrete permeability comes from what factors?

capillary pores, transition zone porosity (high influence from SCM), and microcracks

Three types of tests to type permeability:

thru-put water permeability

absorption tests

gas permeability

chloride diffusion



strength of concrete is a function of:

strength of the paste, nature of the paste aggregate interface, nature of the microcracks, aggregate and cement characteristics, CM content, rate of loading, porosity

What does rate of loading have on concrete strength?

High rate of loading yields an overestimate of the concrete strength. Normal and slow rates of loading allow microcracks to develop and rearrange the matrix

What increases the amount of creep in concrete?

- high loads combined with drying

- lower cement paste content

**relative humidity also affects creep

What are 5 different crack types in concrete?


Autogenous and chemical



Load induced

When does chemical shrinkage occur? How about Autogenous shrinkage?

chemical shrinkage happens when the volume of products is less than the volume of reactants

Autogenous shrinkage is a component of chemical shrinkage; results in external volume change (results in cracking, particularly for high cement content mixes)

What is plastic shrinkage?

evaporative loss when concrete is in plastic state

water goes into tension creating tensile stress in concrete (at surface)

When does plastic shrinkage occur?

hot, dry, or windy conditions

works with autogenous shrinkage to make cracking worse

What can plastic and autogenous shrinkage result in?

reduced durability of structure

aesthetic problems

How is plastic and autogenous shrinkage mitigated?

early moist curing

slowing rate of reaction

less cement in mix

What is drying shrinkage?

time dependent strain due to loss or gain of water

How are thermal cracks made?

heat generated during cement hydration

differential thermal expansion between interior and exterior of element

Name three different types of concrete cracks?

surface cracks, shallow v-shaped (plastic) , deep (drying, thermal, load)

What are the benefits of silica fume?

high strength

low water permeability

improved cohesion or stickiness

high chemical resistance

What are the main steps to the cement making process?

Pre heating, dewatering, calcination (Ca(OH)2 converted to CaO)

Sintering in kiln to produce clinker

Grinding to fine powder, and adding gypsum, limestone, and possible SCM

Which elements lower kiln temperature?

Al and Fe