Slag Cement University

Question 1

True or False: A portion of portland cement can be replaced with Slag Cement to create a stronger and more durable concrete.

Answer 1

True

Question 2

True or False: In concrete, slag cement may be proportioned from 20 to 80% depending on the application.

Answer 2

True

Question 3

Why is the lower heat evolution characteristic of slag cement in the summer beneficial?

Answer 3

Because it allows more time for placing and finishing concrete

Question 4

True or False: The specific gravity of slag cement ranges from 2.85 to 2.94, depending on the source.

Answer 4

True

Question 5

______ is defined as the point in time at which penetration resistance reaches specified values.

Answer 5

Time of initial set

Question 6

True or False: At temperatures greater than 85 degrees Fahrenheit, concrete containing slag cement can have longer times of set.

Answer 6

False

Question 7

______ are an effective way to control cracking due to shrinkage.

Answer 7

Saw-cut joints

Question 8

True or False: The later the concrete can be cut without raveling, the better the chances are that concrete will not crack before saw cutting.

Answer 8

False

Question 9

A concrete mix with quartzite needs to achieve a compressive strength of nearly _____ psi more than a gravel mix before it can be safely saw cut.

Answer 9

800

Question 10

True or False: As a rough guideline, the time to saw cut is delayed approximately 30 minutes for every 20% of slag cement replacing portland cement.

Answer 10

False

Question 11

True or False: Slag cement and Portland cement are stored in a similar manner.

Answer 11

True

Question 12

Slag cement must be stored in ____ or ____ to provide protections from moisture and contamination.

Answer 12

Bins, Silos

Question 13

_____ refers to leveling, smoothing, consolidating and otherwise treating surfaces of fresh, plastic concrete to produce desired surface or appearance.

Answer 13

Finishing

Question 14

Concrete with lower permeability can generally be achieved by substituting between ______ percent slag cement for Portland cement.

Answer 14

25%-65%

Question 15

Slag cement ___ concrete permeability.

Answer 15

Reduces

Question 16

True or False: When reinforcing steel in concrete corrodes, the product of that corrosion (rust) takes up more volume.

Answer 16

True

Question 17

Sulfate attack is a common form of ______

Answer 17

Concrete deterioration

Question 18

True or False: Slag cement can give a Type I cement the sulfate resisting properties of a Type II cement.

Answer 18

True

Question 19

True or False: Slag cement can give a Type I or a Type II cement the sulfate resisting properties of a Type V cement.

Answer 19

True

Question 20

_____ is a chemical reaction between the alkalies in portland cement and certain types of silica minerals present in some aggregates.

Answer 20

Alkali-silica reaction (ASR)

Question 21

True or False: Slag cement can be used to reduce alkali loading in concrete.

Answer 21

True

Question 22

In ASR, the reaction product is _____, which absorbs moisture and swells.

Answer 22

Hygroscopic gel

Question 23

Cement hydration generates _____.

Answer 23

Heat

Question 24

Hardened concrete containing slag cement may show mottled ___ or ___ areas on the surface in the first few days after placement, which goes away within 1-2 weeks.

Answer 24

Green; blue green

Question 25

True or False: Concrete greening does not affect concrete performance.

Answer 25

True

Question 26

The blue-green color, commonly referred to as “greening”, is attributed to a complex reaction of ___________ in slag cement with other compounds in portland cement.

Answer 26

Sulfide Sulphur

Question 27

At normally specified replacement levels, concrete made with slag cement will have lower _________ than concrete made with Class F and C fly ash when tested according to ASTM C1202.

Answer 27

Permeability

Question 28

Slag cement will provide concrete with ______ reflectivity than ordinary portland cement concrete.

Answer 28

Higher

Question 29

Blended cements incorporating slag and portland cement are specified in _______.

Answer 29

ASTM C595

Question 30

ASTM C989 Specifies ________ ground granulated blast-furnace slag for use as a cementitious material in concrete and mortar.

Answer 30

Finely

Question 31

True or False: Slag cement should be used as a pound for pound replacement for a portion of the portland cement in a concrete mixture.

Answer 31

True

Question 32

True or False: If the specific slag/portland cement mixture is shown to mitigate ASR in accordance with ASTM C1778, low alkali cement is necessary.

Answer 32

False

Question 33

___________ is the non-metalic product, consisting essentially of silicates and aluminosilicates of calcium and other bases, which is developed in a molten condition simultaneously with iron in a blast furnace.

Answer 33

Blast furnace slag

Question 34

True or False: Concrete made with slag cement provides higher compressive and flexural strength compared with straight portland cement concrete

Answer 34

True

Question 35

_____ day strengths generally increase as the percentage of slag cement increases, up to about 50% slag cement as a percent of cementitious material.

Answer 35

28

Question 36

What product created from portland cement reacting with water is beneficially utilized by slag cement to improve the strength and permeability properties of concrete?

Answer 36

Calcium hydrate

Question 37

Concrete flexural strengths in excess of ______ psi are common with mixes containing slag cement.

Answer 37

1,000

Question 38

When used at ______ replacement rates, slag cement will provide _______ heat in mass concrete.

Answer 38

High, lower

Question 39

Engineers and concrete producers who have successfully incorporated slag cement in their HPC mixtures have used slag cement in ranges from ________ percent of cementitious material.

Answer 39

20 to 80

Question 40

True or False: Slag cement can improve both the plastic and hardened properties of precast and prestressed concrete.

Answer 40

True

Question 41

Slag cement _________ concrete permeability, which in turn increases resistance to chloride intrusion.

Answer 41

Reduces

Question 42

Slag cement improves the workability of concrete due to its _______ and ________ structure.

Answer 42

Fine grind, glassy

Question 43

True or False: Slag cement is not an ideal material for concrete pipe.

Answer 43

False

Question 44

Elevated curing temperatures _________ early age strength development in mixtures containing slag cement

Answer 44

Activate

Question 45

Slag cement ________ surface texture and density when used in concrete block mixtures.

Answer 45

Improves

Question 46

At ______ days, strengths are superior when concrete pipe is manufactured with slag cement.

Answer 46

28

Question 47

Block manufactured with slag cement will have a ______ finished color.

Answer 47

Lighter

Question 48

Slag cement combines with _____________ and ___________ in portland cement to reduce efflorescence.

Answer 48

Calcium hydroxide & soluble salts

Question 49

True or False: Slag cement is advantageous in decorative concrete because of its lighter color?

Answer 49

True

Question 50

Ternary concrete mixtures include ______ different cementitious materials.

Answer 50

3

Question 51

True or False: Ternary blends have performed for many years in severe conditions with no apparent loss of durability.

Answer 51

True

Question 52

Ternary mixtures can be used in ______ concrete applications.

Answer 52

Any

Question 53

Utilization of slag cement in concrete _______ the burden on landfills

Answer 53

Lessens

Question 54

In high performance and mass concrete applications slag cement can be used as a substitute up to ______ percent.

Answer 54

80%

Question 55

Slag cement requires nearly _____ percent less energy to produce than and equivalent amount of portland cement.

Answer 55

90%

Question 56

Because slag cement has a lighter color it reduces the “________” effect.

Answer 56

Heat island

Question 57

How is slag cement manufactured?

Answer 57

Slag cement is formed when molten slag, diverted from an iron blast furnace, is rapidly quenched producing glassy granules ground to cement fineness.

Question 58

Slag cement particles have a _________ structure/shape.

Answer 58

Glassy/angular

Question 59

True or False: Slag cement composition is closer to portland cement than other SCMs.

Answer 59

True

Question 60

The reaction of cement and water will produce two primary hydration products:

Answer 60

Calcium Silica Hydrate (CSH) and Calcium Hydroxide (CaOH)

Question 61

True or False: Slag cements time of set increases versus reference portland cement by ½ to 1 hour at 73 degrees Fahrenheit (23 degrees Celsius). There is little change above 85 degrees Fahrenheit.

Answer 61

True

Question 62

Slag cement ________ the total alkalis in the system, _________ the alkali-silica ratio and the potential for alkali silica reaction (ASR).

Answer 62

Reduces, reduces

Question 63

Slag cement use leads to lower heat of hydration in mass concrete by __________% compared to portland cement concrete.

Answer 63

15-50%

Question 64

True or False: Concrete made with slag cement tends to be lighter and brighter in color with more reflectivity than mix designs with only portland cement.

Answer 64

True

Question 65

What does the Life Cycle Assessment Calculator for Slag Cement do?

Answer 65

Shows comparisons of environmental impact of various mix designs with slag cement at various percentage replacement rates, based on industry wide Environmental Product Declaration information.