AR CM Concrete Masonry Contractor
Exam Questions and Correct Answers
(Verified Answers) Plus Rationale 2027
Q&A| Instant Download Pdf
1. What is the primary function of mortar in concrete masonry
construction?
A. To replace all reinforcement in masonry walls
B. To increase the weight of the wall
C. To bond masonry units together and distribute loads across their
bearing surfaces
D. To eliminate the need for proper foundation construction
Rationale: Mortar bonds masonry units into a cohesive assembly,
helps distribute compressive forces across the joints, and
,accommodates minor variations in unit dimensions. It also helps seal
joints against water penetration. Mortar does not replace structural
reinforcement or compensate for an inadequate foundation.
2. Which ASTM standard specifies concrete masonry units used in load-
bearing walls?
A. ASTM C150
B. ASTM C90
C. ASTM C33
D. ASTM C143
Rationale: ASTM C90 establishes requirements for load-bearing
concrete masonry units, including physical properties, dimensions, and
applicable strength and absorption requirements. ASTM C150 covers
portland cement, ASTM C33 covers concrete aggregates, and ASTM
C143 addresses the slump test for hydraulic-cement concrete.
3. What is the primary purpose of a concrete masonry wall's
foundation?
A. To provide a decorative surface
B. To prevent mortar from hardening
C. To eliminate lateral soil pressure
,D. To transfer wall loads safely to the supporting soil
Rationale: Foundations distribute structural loads to the supporting
soil without exceeding its allowable bearing capacity. Proper
foundation design also addresses settlement, frost conditions where
applicable, groundwater, and structural stability. An inadequate
foundation can cause cracking, differential settlement, and wall
failure.
4. Which material is commonly used to reinforce concrete masonry
walls vertically?
A. Wood dowels
B. Plastic rods
C. Deformed steel reinforcing bars
D. Aluminum flashing
Rationale: Deformed steel reinforcing bars are commonly placed
vertically in reinforced masonry cells and embedded in grout. Their
deformations improve bond with the surrounding grout.
Reinforcement helps resist tensile forces and bending, particularly in
walls subjected to wind, seismic, or other lateral loads.
5. What is the main purpose of grout in reinforced concrete masonry?
, A. To lubricate masonry units during installation
B. To replace all mortar joints
C. To embed reinforcement and transfer stresses between the
reinforcement and masonry assembly
D. To prevent concrete masonry units from absorbing any moisture
Rationale: Masonry grout fills designated spaces within masonry
construction, surrounds reinforcing steel, and transfers stresses
between the steel and surrounding masonry. Proper consolidation and
placement are necessary to avoid voids that could compromise
structural performance.
6. Which tool is commonly used to spread mortar onto a concrete
masonry unit?
A. Pipe wrench
B. Masonry trowel
C. Bolt cutter
D. Chalk line
Rationale: A masonry trowel is used to scoop, spread, shape, and
place mortar on bed and head joints. The mason uses it to control
Exam Questions and Correct Answers
(Verified Answers) Plus Rationale 2027
Q&A| Instant Download Pdf
1. What is the primary function of mortar in concrete masonry
construction?
A. To replace all reinforcement in masonry walls
B. To increase the weight of the wall
C. To bond masonry units together and distribute loads across their
bearing surfaces
D. To eliminate the need for proper foundation construction
Rationale: Mortar bonds masonry units into a cohesive assembly,
helps distribute compressive forces across the joints, and
,accommodates minor variations in unit dimensions. It also helps seal
joints against water penetration. Mortar does not replace structural
reinforcement or compensate for an inadequate foundation.
2. Which ASTM standard specifies concrete masonry units used in load-
bearing walls?
A. ASTM C150
B. ASTM C90
C. ASTM C33
D. ASTM C143
Rationale: ASTM C90 establishes requirements for load-bearing
concrete masonry units, including physical properties, dimensions, and
applicable strength and absorption requirements. ASTM C150 covers
portland cement, ASTM C33 covers concrete aggregates, and ASTM
C143 addresses the slump test for hydraulic-cement concrete.
3. What is the primary purpose of a concrete masonry wall's
foundation?
A. To provide a decorative surface
B. To prevent mortar from hardening
C. To eliminate lateral soil pressure
,D. To transfer wall loads safely to the supporting soil
Rationale: Foundations distribute structural loads to the supporting
soil without exceeding its allowable bearing capacity. Proper
foundation design also addresses settlement, frost conditions where
applicable, groundwater, and structural stability. An inadequate
foundation can cause cracking, differential settlement, and wall
failure.
4. Which material is commonly used to reinforce concrete masonry
walls vertically?
A. Wood dowels
B. Plastic rods
C. Deformed steel reinforcing bars
D. Aluminum flashing
Rationale: Deformed steel reinforcing bars are commonly placed
vertically in reinforced masonry cells and embedded in grout. Their
deformations improve bond with the surrounding grout.
Reinforcement helps resist tensile forces and bending, particularly in
walls subjected to wind, seismic, or other lateral loads.
5. What is the main purpose of grout in reinforced concrete masonry?
, A. To lubricate masonry units during installation
B. To replace all mortar joints
C. To embed reinforcement and transfer stresses between the
reinforcement and masonry assembly
D. To prevent concrete masonry units from absorbing any moisture
Rationale: Masonry grout fills designated spaces within masonry
construction, surrounds reinforcing steel, and transfers stresses
between the steel and surrounding masonry. Proper consolidation and
placement are necessary to avoid voids that could compromise
structural performance.
6. Which tool is commonly used to spread mortar onto a concrete
masonry unit?
A. Pipe wrench
B. Masonry trowel
C. Bolt cutter
D. Chalk line
Rationale: A masonry trowel is used to scoop, spread, shape, and
place mortar on bed and head joints. The mason uses it to control
