CE 337 EXAM 2 – PCC QUESTIONS AND CORRECT
ANSWERS
The constituents of cement mortar include... - answers - cement, water, & sand or fine
aggregate
Which compounds (not hydration product) provides alkalis to cement? - answers - na2o,
k2o
Gypsum is inter-ground with clinker for what reasons? - answers - to supply sulfate ions
The 28 day compressive strength for normal concrete ranges between what psi? -
answers - 3000-6000psi
C3a + water + _______ -> ________ + heat - answers - c3a+water+gypsum ->
ettringinte + heat
Unit weight range of normal concrete ? - answers - 140-150 lb/ft^3
The specific gravity of portland cement ranges from...? - answers - 3.12-3.16
One way to achieve sulfate resistance in portland cement concrete is to use type ii or v
cements. Sulfate resistance is obtained by reducing (which chemical compound)? -
answers - c3a
The ideal ph for the hydration reaction to be efficient is...? - answers - 12 or higher
Curing is defined as the management of what? - answers - management of temperature
and moisture
The different void types formed as results of the hydration process include...? - answers
- csh (interparticle space), air voids, capillary voids
Initial set time for type iv cement paste is...? - answers - longer than type i
The c2s content in type iii cement is...? - answers - less than type i
The c3a content in type iv cement is....? - answers - less than type i
The c3s content in type iii cement is...? - answers - more than type i
The duration of the nucleation stage for type iv cement is...? - answers - longer than
type i
, Three characteristics of the hydration reaction - answers - -exothermic reaction
-reaction between h2o & cement
-surface reaction
-size of cement grains reduce as hydration products are formed
List two differences between csh & ch. - answers - csh-strength giver, fibrous
Ch-ph builder, crystalline
Which type of cement would one use for..."a floor slab 4' thick, 50' long & 60' wide"? -
answers - type iv, because it has a low heat of hydration
Which type of cement would one use for..."a pavement repair path (emergency
situation)"? - answers - type iii, because it has early strength gain
Which type of cement would one use for..."inside lining of a sewer tank"? - answers -
type ii, because it is sulfate resistant
Ingredients of cement paste? - answers - cement & water
Ingredients of mortar? - answers - cement, water, & fine aggregate
Ingredients of concrete? - answers - cement, water, fine aggregate, & coarse aggregate
States of concrete - answers - -fresh/plastic state (2-4 hrs)
-hardening state (4-8 hrs)
-hardened state
Will air entrained pcc mix be stronger or less strong than non-air entrain pcc? - answers
- less strong
28 day flexural strength of concrete - answers - 500-750psi
Coefficient of thermal expansion for concrete - answers - 4-6 ue/f
Permeability of concrete - answers - 10^-3 - 10^-4 mm/sec
Chemical composition of pcc - answers - main compounds: c3s, c2s, csa, c3af, gypsum
Minor compounds: magnesium oxide, titanium oxide, mangenese oxide, sodium oxide,
potassium oxide
Characteristics of c3s (tri-calcium silicate) - answers - significant impact on early
concrete strength
Characteristics of c2s (di-calcium silicate) - answers - significant impact on late term
concrete strength
ANSWERS
The constituents of cement mortar include... - answers - cement, water, & sand or fine
aggregate
Which compounds (not hydration product) provides alkalis to cement? - answers - na2o,
k2o
Gypsum is inter-ground with clinker for what reasons? - answers - to supply sulfate ions
The 28 day compressive strength for normal concrete ranges between what psi? -
answers - 3000-6000psi
C3a + water + _______ -> ________ + heat - answers - c3a+water+gypsum ->
ettringinte + heat
Unit weight range of normal concrete ? - answers - 140-150 lb/ft^3
The specific gravity of portland cement ranges from...? - answers - 3.12-3.16
One way to achieve sulfate resistance in portland cement concrete is to use type ii or v
cements. Sulfate resistance is obtained by reducing (which chemical compound)? -
answers - c3a
The ideal ph for the hydration reaction to be efficient is...? - answers - 12 or higher
Curing is defined as the management of what? - answers - management of temperature
and moisture
The different void types formed as results of the hydration process include...? - answers
- csh (interparticle space), air voids, capillary voids
Initial set time for type iv cement paste is...? - answers - longer than type i
The c2s content in type iii cement is...? - answers - less than type i
The c3a content in type iv cement is....? - answers - less than type i
The c3s content in type iii cement is...? - answers - more than type i
The duration of the nucleation stage for type iv cement is...? - answers - longer than
type i
, Three characteristics of the hydration reaction - answers - -exothermic reaction
-reaction between h2o & cement
-surface reaction
-size of cement grains reduce as hydration products are formed
List two differences between csh & ch. - answers - csh-strength giver, fibrous
Ch-ph builder, crystalline
Which type of cement would one use for..."a floor slab 4' thick, 50' long & 60' wide"? -
answers - type iv, because it has a low heat of hydration
Which type of cement would one use for..."a pavement repair path (emergency
situation)"? - answers - type iii, because it has early strength gain
Which type of cement would one use for..."inside lining of a sewer tank"? - answers -
type ii, because it is sulfate resistant
Ingredients of cement paste? - answers - cement & water
Ingredients of mortar? - answers - cement, water, & fine aggregate
Ingredients of concrete? - answers - cement, water, fine aggregate, & coarse aggregate
States of concrete - answers - -fresh/plastic state (2-4 hrs)
-hardening state (4-8 hrs)
-hardened state
Will air entrained pcc mix be stronger or less strong than non-air entrain pcc? - answers
- less strong
28 day flexural strength of concrete - answers - 500-750psi
Coefficient of thermal expansion for concrete - answers - 4-6 ue/f
Permeability of concrete - answers - 10^-3 - 10^-4 mm/sec
Chemical composition of pcc - answers - main compounds: c3s, c2s, csa, c3af, gypsum
Minor compounds: magnesium oxide, titanium oxide, mangenese oxide, sodium oxide,
potassium oxide
Characteristics of c3s (tri-calcium silicate) - answers - significant impact on early
concrete strength
Characteristics of c2s (di-calcium silicate) - answers - significant impact on late term
concrete strength
