APA Precast Concrete Batch Plant Operator
Questions And Answers 2023
Concrete is a mixture of _____, ______, and ______. ...ANSWER...cement, water, and aggregates.
The most commonly used concrete for structural purposes is: ...ANSWER...Normal weight concrete.
Normal weight concrete weighs approximately: ...ANSWER...140 lb/ft^3
Lightweight structural concrete may weigh from _____ to ______ lb/ft^3. ...ANSWER...90, 100
Heavyweight concrete may weigh ______. ...ANSWER...200 lb/ft^3 or more.
Most concrete today is made with: ...ANSWER...Portland Cement
Concrete is usually referred to as a mixture of two components; ______ and
_______. ...ANSWER...aggregate, paste
The hardening process of the paste is a chemical reaction called _________. ...ANSWER...Hydration
_______ is developed in the hydration process. It may peak up to _______
degrees. ...ANSWER...heat;130 F
Concrete does hardens and cures by drying. True or False ...ANSWER...False ; Concrete does not harden
or cure by drying, because cement needs moisture to hydrate and gain strength. When concrete dries
fully, hydration stops, and it no longer gains strength.
, A mixture of cement and water is called: ...ANSWER...paste
When sand is added to paste it is called: ...ANSWER...mortar or grout
When coarse aggregate is added to mortar, the combination is called ______. ...ANSWER...concrete
________ make up about 60 to 75% of the volume of concrete ...ANSWER...Aggregates
The particle size distribution or combined coarse and fine aggregate gradation should have all sizes
present in adequate amounts. True or False ...ANSWER...True. If the gradation is evenly distributed
adequately the void content to be filled by the cement paste is minimized. This process produces a
concrete that will hold together without segregating and will minimize the need for cement or
cementitious content.
Minimizing the cement in the mixture also benefits ________ stability, _______ development, and
_________. ...ANSWER...volume, heat, durability
There are primarily two types of aggregates, _______ or ________. ...ANSWER...crushed, natural
Crushed aggregates can be either coarse or fine. True or False ...ANSWER...True
Crushed aggregates were naturally formed and then _______ and _______. ...ANSWER...mined, crushed
Crushed aggregates are also referred to as ________ aggregates ...ANSWER...manufactured aggregates
Natural aggregates can be coarse or fine. True or False ...ANSWER...True
Natural aggregates are those that are used in concrete in the state they exist in
________. ...ANSWER...nature
Questions And Answers 2023
Concrete is a mixture of _____, ______, and ______. ...ANSWER...cement, water, and aggregates.
The most commonly used concrete for structural purposes is: ...ANSWER...Normal weight concrete.
Normal weight concrete weighs approximately: ...ANSWER...140 lb/ft^3
Lightweight structural concrete may weigh from _____ to ______ lb/ft^3. ...ANSWER...90, 100
Heavyweight concrete may weigh ______. ...ANSWER...200 lb/ft^3 or more.
Most concrete today is made with: ...ANSWER...Portland Cement
Concrete is usually referred to as a mixture of two components; ______ and
_______. ...ANSWER...aggregate, paste
The hardening process of the paste is a chemical reaction called _________. ...ANSWER...Hydration
_______ is developed in the hydration process. It may peak up to _______
degrees. ...ANSWER...heat;130 F
Concrete does hardens and cures by drying. True or False ...ANSWER...False ; Concrete does not harden
or cure by drying, because cement needs moisture to hydrate and gain strength. When concrete dries
fully, hydration stops, and it no longer gains strength.
, A mixture of cement and water is called: ...ANSWER...paste
When sand is added to paste it is called: ...ANSWER...mortar or grout
When coarse aggregate is added to mortar, the combination is called ______. ...ANSWER...concrete
________ make up about 60 to 75% of the volume of concrete ...ANSWER...Aggregates
The particle size distribution or combined coarse and fine aggregate gradation should have all sizes
present in adequate amounts. True or False ...ANSWER...True. If the gradation is evenly distributed
adequately the void content to be filled by the cement paste is minimized. This process produces a
concrete that will hold together without segregating and will minimize the need for cement or
cementitious content.
Minimizing the cement in the mixture also benefits ________ stability, _______ development, and
_________. ...ANSWER...volume, heat, durability
There are primarily two types of aggregates, _______ or ________. ...ANSWER...crushed, natural
Crushed aggregates can be either coarse or fine. True or False ...ANSWER...True
Crushed aggregates were naturally formed and then _______ and _______. ...ANSWER...mined, crushed
Crushed aggregates are also referred to as ________ aggregates ...ANSWER...manufactured aggregates
Natural aggregates can be coarse or fine. True or False ...ANSWER...True
Natural aggregates are those that are used in concrete in the state they exist in
________. ...ANSWER...nature
