Slag Cement University Flashcards
Study for the Slag Cement University Exam
True or False: A portion of portland cement can be replaced with Slag Cement to create a stronger and more durable concrete.
True
True or False: In concrete, slag cement may be proportioned from 20 to 80% depending on the application.
True
Why is the lower heat evolution characteristic of slag cement in the summer beneficial?
Because it allows more time for placing and finishing concrete
True or False: The specific gravity of slag cement ranges from 2.85 to 2.94, depending on the source.
True
______ is defined as the point in time at which penetration resistance reaches specified values.
Time of initial set
True or False: At temperatures greater than 85 degrees Fahrenheit, concrete containing slag cement can have longer times of set.
False
______ are an effective way to control cracking due to shrinkage.
Saw-cut joints
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.
False
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.
800
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.
False
True or False: Slag cement and Portland cement are stored in a similar manner.
True
Slag cement must be stored in ____ or ____ to provide protections from moisture and contamination.
Bins, Silos
_____ refers to leveling, smoothing, consolidating and otherwise treating surfaces of fresh, plastic concrete to produce desired surface or appearance.
Finishing
Concrete with lower permeability can generally be achieved by substituting between ______ percent slag cement for Portland cement.
25%-65%
Slag cement ___ concrete permeability.
Reduces
True or False: When reinforcing steel in concrete corrodes, the product of that corrosion (rust) takes up more volume.
True
Sulfate attack is a common form of ______
Concrete deterioration
True or False: Slag cement can give a Type I cement the sulfate resisting properties of a Type II cement.
True
True or False: Slag cement can give a Type I or a Type II cement the sulfate resisting properties of a Type V cement.
True
_____ is a chemical reaction between the alkalies in portland cement and certain types of silica minerals present in some aggregates.
Alkali-silica reaction (ASR)
True or False: Slag cement can be used to reduce alkali loading in concrete.
True
In ASR, the reaction product is _____, which absorbs moisture and swells.
Hygroscopic gel
Cement hydration generates _____.
Heat
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.
Green; blue green
True or False: Concrete greening does not affect concrete performance.
True
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.
Sulfide Sulphur
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.
Permeability
Slag cement will provide concrete with ______ reflectivity than ordinary portland cement concrete.
Higher
Blended cements incorporating slag and portland cement are specified in _______.
ASTM C595
ASTM C989 Specifies ________ ground granulated blast-furnace slag for use as a cementitious material in concrete and mortar.
Finely
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.
True
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.
False
___________ 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.
Blast furnace slag
True or False: Concrete made with slag cement provides higher compressive and flexural strength compared with straight portland cement concrete
True
_____ day strengths generally increase as the percentage of slag cement increases, up to about 50% slag cement as a percent of cementitious material.
28
What product created from portland cement reacting with water is beneficially utilized by slag cement to improve the strength and permeability properties of concrete?
Calcium hydrate
Concrete flexural strengths in excess of ______ psi are common with mixes containing slag cement.
1,000
When used at ______ replacement rates, slag cement will provide _______ heat in mass concrete.
High, lower
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.
20 to 80
True or False: Slag cement can improve both the plastic and hardened properties of precast and prestressed concrete.
True
Slag cement _________ concrete permeability, which in turn increases resistance to chloride intrusion.
Reduces
Slag cement improves the workability of concrete due to its _______ and ________ structure.
Fine grind, glassy
True or False: Slag cement is not an ideal material for concrete pipe.
False
Elevated curing temperatures _________ early age strength development in mixtures containing slag cement
Activate
Slag cement ________ surface texture and density when used in concrete block mixtures.
Improves
At ______ days, strengths are superior when concrete pipe is manufactured with slag cement.
28
Block manufactured with slag cement will have a ______ finished color.
Lighter
Slag cement combines with _____________ and ___________ in portland cement to reduce efflorescence.
Calcium hydroxide & soluble salts
True or False: Slag cement is advantageous in decorative concrete because of its lighter color?
True
Ternary concrete mixtures include ______ different cementitious materials.
3
True or False: Ternary blends have performed for many years in severe conditions with no apparent loss of durability.
True
Ternary mixtures can be used in ______ concrete applications.
Any
Utilization of slag cement in concrete _______ the burden on landfills
Lessens
In high performance and mass concrete applications slag cement can be used as a substitute up to ______ percent.
80%
Slag cement requires nearly _____ percent less energy to produce than and equivalent amount of portland cement.
90%
Because slag cement has a lighter color it reduces the “________” effect.
Heat island
How is slag cement manufactured?
Slag cement is formed when molten slag, diverted from an iron blast furnace, is rapidly quenched producing glassy granules ground to cement fineness.
Slag cement particles have a _________ structure/shape.
Glassy/angular
True or False: Slag cement composition is closer to portland cement than other SCMs.
True
The reaction of cement and water will produce two primary hydration products:
Calcium Silica Hydrate (CSH) and Calcium Hydroxide (CaOH)
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.
True
Slag cement ________ the total alkalis in the system, _________ the alkali-silica ratio and the potential for alkali silica reaction (ASR).
Reduces, reduces
Slag cement use leads to lower heat of hydration in mass concrete by __________% compared to portland cement concrete.
15-50%
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.
True
What does the Life Cycle Assessment Calculator for Slag Cement do?
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.
