4 – Designing Concrete Mixes

Which of the following is NOT an objective of concrete-mix design?

Which of the following is a characteristic of workable fresh concrete?

Which of the following is a characteristic of quality hardened concrete?

Which of the following is a characteristic of an economical concrete mix?

State steps in determining optimum concrete-mix design. Choose the word or words that correctly completes the following statements.

________ are determined.

State steps in determining optimum concrete-mix design. Choose the word or words that correctly completes the following statements.

________ design factors are determined to meet job requirements.

State steps in determining optimum concrete-mix design. Choose the word or words that correctly completes the following statements.

________ are mixed to determine optimum mix design.

Which of the following are requirements that must be determined before a concrete mix is designed?

Name concrete-mix design factors determined to meet job requirements. Each of the items below is a concrete-mix design factor determined to meet job requirements. Choose the letter of the word that goes in each blank.

Maximum permissible water/________ ratio

Name concrete-mix design factors determined to meet job requirements. Each of the items below is a concrete-mix design factor determined to meet job requirements. Choose the letter of the word that goes in each blank.

Maximum coarse ________ size

Name concrete-mix design factors determined to meet job requirements. Each of the items below is a concrete-mix design factor determined to meet job requirements. Choose the letter of the word that goes in each blank.

Total ________ content

Name concrete-mix design factors determined to meet job requirements. Each of the items below is a concrete-mix design factor determined to meet job requirements. Choose the letter of the word that goes in each blank.

Range of ________

Maximum course aggregate size should NOT exceed ________ of the minimum dimension of the member to be constructed.

Maximum course aggregate size should NOT exceed ________ of the clear space between reinforcing bars or between reinforcement bars and forms.

Maximum course aggregate size should NOT exceed ________ of the thickness of unreinforced slabs.

Which of the following are NOT methods to determine optimum mix proportions?

What is the main benefit of air-entrained concrete?

What is one way of introducing air into the concrete mixture?

Air-entrained concrete should be finished

The amount of air in air-entrained concrete is

State types of mix designs and their definitions. Match the type of mix design with its definition.

Mix containing a high proportion of cement

tate types of mix designs and their definitions. Match the type of mix design with its definition.

Mix containing a low proportion of cement

Which of the following types of concrete has a unit weight of 90 to 115 pounds per cubic foot?

Which of the following is an insulating type of concrete made with aggregates of expanded materials such as perlite or vermiculite?

Which of the following types of concrete has a unit weight of approximately 150 pounds per cubic foot?

Which of the following types of concrete is made with aggregates such as barite, ferrophosphorous, goethite, hematite, ilmenite, limonite, magnetite, steel punchings, and steel shots?

Which of the following is NOT a factor used in selecting aggregate for heavyweight concrete?

Lightweight, group II concrete is used in making light but strong structural members such as those needed in high rise buildings.

Heavyweight concrete is used in standard concrete construction.

Lightweight, group I concrete is used for insulating members such as roofs, fire walls, and conduit linings.

Mixing requirements for stationary mixers are for ________ minute(s).

Mixing requirements for truck mixers are for ________ to ________ revolutions at mixing speed designated by the mixer manufacturer.

Standard discharge time for a stationary mixer is within ________ after the introduction of water into the tank.

Admixtures modify the properties of hardened concrete.

Admixtures can create emergencies or difficult construction situations.

Admixtures can help improve the appearance of the concrete over time.

Accelerating admixtures are used during ________ weather to speed up the setting process and early strength development.

Air-entraining admixtures introduce tiny air cells into the concrete to improve ________ resistance.

Plasticizers/superplasticizers are used to greatly reduce the amount of mix water needed and to increase ________.

Retarding admixtures are used to offset the accelerating effects of ________ weather on the setting process.

Specialty admixtures are used for specific functions, such as to reduce ALL BUT WHICH of the following:

Water-reducing admixtures are used to reduce the amount of ________ needed for a given consistency.