Unit 3 Part 2

Question 1

This method covers determination of the density of hydraulic cement. Its particular usefulness is in connection with the design and control of concrete mixtures.

Answer 1

Standard Method of Test for Density of Hydraulic Cement (AASHTO T-133 / ASTM C 188)

Question 2

• is defined as the mass of a unit volume of the solids.

Answer 2

The density of hydraulic cement

Question 3

(AASHTO T-133 / ASTM C 188)

Answer 3

SPECIFIC GRAVITY

Question 4

Both_________ and _________ are influenced by fineness. Increasing the fineness substantially increase the rate of hydration.

Answer 4

FINENESS (AASHTO T-128 / ASTM C 184),strength
permeability

Question 5

To determine whether or not the hydraulic cement under test meets the air-entraining or non-air-entraining requirements of the applicable hydraulic cement specification.

Answer 5

AIR CONTENT (ASTM C 185)

Question 6

Controls the ability to withstand cycles of freezing and thawing.

Answer 6

AIR CONTENT (ASTM C 185)

Question 7

To determine the amount of water required to prepare hydraulic pastes for testing.

Answer 7

Normal Consistency (ASTM C187)

Question 8

Cement consistency generally assumed to affect concrete workability.

Answer 8

Normal Consistency (ASTM C187)

Question 9

Measures the penetration resistance of cement paste or mortar.

Answer 9

TIME SETTING Using Vicat Needle (AASHTO T-131 ASTM C 191)

Question 10

To ensure that the cement does not produce abnormal setting time or to test the reaction of cement and chemical admixture.

Answer 10

TIME SETTING Using Vicat Needle (AASHTO T-131 ASTM C 191)

Question 11

• refers to the stiffening of the cement paste or the change from plastic state to a solid state.

Answer 11

Setting

Question 12

• mainly develop by a selective hydration of tricalcium aluminate (C3A) and tricalcium silicate (C3S) and is accompanied by temperature rises in the cement paste;
  ___________ corresponds to a rapid rise and _________corresponds to the peak temperature. Initial and final sets should be distinguished from false set which sometimes occurs within a few minutes of mixing with water (ASTM C451). No heat is evolved in a _________ and the concrete can be remixed without adding water. _________ on the other hand, is characterized by the liberation of heat.

Answer 12

Setting, Initial set , final set, false set, Flash set

Question 13

Provides an index of potential delayed expansion caused by hydration of free lime (CaO)or MgO or both.

Answer 13

SOUNDNESS DETERMINATION BY AUTOCLAVE EXPANSION (AASHTO T-107 / ASTM C 151)

Question 14

• is the weight percentage lost when Portland cement is heated at 950±50°C

Answer 14

LOSS ON IGNITION (LOI) ASTM C114

Question 15

• was added in cement specification to prevent the addition of carbonate minerals such as limestone and dolomite.

Answer 15

LOSS ON IGNITION (LOI) ASTM C114

Question 16

The limits is set in order to prevent adulteration or contamination of cement with _________ and _________ components.

Answer 16

INSOLUBLE RESIDUE (IR), siliceous,
argillaceous

Question 17

All Portland cements contains IR from silicate impurities of _______(CaSO4) added during the _______ grinding process.

Answer 17

T,gypsum, final

Question 18

• regulates the initial setting and hardening reactions that take place during hydration

Answer 18

SULFUR TRIOXIDE (SO₃)

Question 19

• above a certain optimum % causes a decrease in strength and an increase in expansion.

Answer 19

SULFUR TRIOXIDE (SO₃)

Question 20

• is being limited because of concern about expansion that can occur if free MgO as periclase hydrates to form Mg(OH)₂ at room temperature.

Answer 20

MAGNESIA (MgO)