Concrete Final (1,2,3,4

The letter "P" in Type IP(15) cement" stands for _______

Pozzolan

What type of admixture is suitable for the situation below. Workers are pouring a large concrete slab in a hot summer day. The concrete would set too fast before they can finish the work.

Set retarder

Which of the following SCMs has a negative effect on the workability of freshly mixed concrete?

Silica fume

Which of the following SCMs has the smallest average particle size?

Silica fume

Match the SCM with the source

Silica fume - by product of the production of silicon metals and ferrosilicon alloys Slag cement - by product from the production of iron used in steel making fly ash - by product of the combustion of pulverized coal in electric power generating plants

Which statement is correct about using site water as mixing water in concrete?

Site water containing significant amount of suspended particles should be tested before use

Write down the full term of acronym "SCM"

Supplementary Cementitious Materials

Almost any water that is drinkable and has no pronounced taste or order can be used as mixing water in concrete

True

Initial setting time is the time that elapses from the moment water is added until the paste ceases to be fluid and plastic

True

The majority of SCMs typically have a lower heat of hydration than Portland cement. They can be used to make low-heat blend cement

True

The use of SCMs will generally increased the setting time of concrete

True

Which of the following cements is most suitable for building a foundation slab in a high-sulfate soil?

Type V

Besides using accelerator, what else can be done to increase the early strength of concrete?

Use blended cement IS

Besides using air-entrainer, what else can be done to increase entrained air content in concrete?

Use fly ash in the mix design

Besides using water reducer, what else can be done to improve the workability of freshly mixed concrete without increasing w/cm

Use fly ash in the mix design

When silica fume is used to make high-strength concrete, what is the best way to solvate problem of reduced workability of the mixture?

Use high-range water reducer admixture

Why did Joseph Aspdin name his patented product as "Portland Cement"?

When set, the cement resembled the color of the natural limestone quarried on the Isle of Portland

A pozzolan is a siliceous or aluminosiliceous material that, in finely divided form and in the presence of moisture, chemically reacts with the _________ to form calcium silicate hydrate and other cementitious compounds

calcium hydroxide

The main reason to increase the amount of entrained air in concrete is to improve __________ of concrete

durability under freezing/thawing

The air entraining (such as Type IIA) cements are usually used to

improve the structure's resistance to freezing and thawing

Calculate the water-to-cement ratio (w/c) for the mix design below:

water/cement = 280/600 = 0.4666 = 46.67%

ASTM C 94, Standard Specification for Ready-Mixed Concrete required the concrete be delivered and placed

within 90 minutes after the addition of water

LEED v4 gives one point credit for "heat island reduction". To achieve this point, one of the options is to use material with a initial solar reflectance of 0.33 or above. What is the typical initial solar reflectance of newly placed concrete?

0.35-0.45

List four advantages of concrete as a structure material compared to steel and timber

1. Compressive strength 2. Tensile strength 3. Fire resistance 4. Durability 5. Mold-ability 6. Low maintenance 7. Rigidity

Read textbook Page 68, the typical dosage of Class F fly ash used in concrete is ______ by mass of cementitious material

15% to 25%

According to ASTM C the required average 7-day compression strength for Type I Portland cement mortar cube sample?

19 MPa

What is the % of slag in Type IS(30) cement?

30

Seawater containing up to ________ of dissolved salts is generally suitable for making concrete that does not contain reinforcing steel

35,000

What is the % of Portland cement in Type IT(S35)(P15) cement?

50

list the Materials used in concrete by absolute volume from large to small

Aggregates (1) Water (2) Cement (3) Air (4)

According to ASTM 1602, what are the criteria to accept a questionable water source?

All of the above

which statement is correct about the impact of air-entrainer on the properties of concrete?

All of the above (it increases the air content of concrete, it improves free/thaw resistance of concrete, it reduces the long-term strength of concrete)

What can we expect if Class F fly ash is used as SCM in the concrete?

All of the above (lower early strength, higher sulfate resistance, lower permeability of hardened concrete)

Which statement is correct?

As the water-to-cement ratio increases, the strength of the concrete reduces

Which phase of cement is responsible more for the long term strength (after four weeks of placement) of concrete?

C2S

Sulfate resistant cements usually have a lower percentage of ______ in it

C3A

The shorthand form of tricalcium aluminate is

C3A

What is most abundant phase in Portland cement?

C3S

Which hydration product of cement bonds the aggregates together and provide the great strength in concrete?

CSH

Which of these is NOT a raw material needed for manufacture of Portland cement?

Carbon

Which statement is correct about set accelerators

Chloride based accelerators are not suitable for use in reinforced concrete

Which class of fly ash has both cementitious and pozzolanic properties?

Class C

Which of the following SCMs has the most profound effect on reducing bleeding of freshly mixed concrete?

Class C fly ash

In a cement plant, the granular product coming out of the rotary kiln (after burning) is called _______ .

Clinker

Why is seawater with high chloride content not suitable for use in steel reinforced concrete?

Corrosion to reinforcement

Which of the following is not a typical component in making concrete?

Dirt

What is the speciality of Type III cement?

Early strength

Portland cement is not a hydraulic cement because it is very stable underwater after set

False

Supplementary cementing materials generally reduces the required amount of air-entraining admixture necessary because the hydration of SCMs generates a lot of tiny air bubbles

False

The setting time of concrete generally increases at higher air temperature

False

What is the most widely used SCM in concrete?

Fly ash

Which SCM has the most beneficial effect on water demand?

Fly ash

what is the speciality of Type GU cement?

General use

In cement plant, ______ is added to clinker before the final grinding to regulate the setting time of cement.

Gypsum

What type of admixture is suitable for the situation below. A project calls for 2" thick concrete overlay on a existing pavement

High-range water reducer

what can we expect if grade 100 slag cement is used as SCM in the concrete?

Higher long term strength

Based on Table 3-3 in the textbook, which of the following blended cement can be used in place of Type IV Portland cement?

IT (P25)(S15)