AZ L-27 Masonry Contractor Exam
Questions and Correct Answers
(Verified Answers) Plus Rationale 2027
Q&A| Instant Download Pdf
Section 1: Masonry Materials and Fundamentals
1. Which material is primarily responsible for binding masonry units
together in a conventional brick wall?
a. Coarse aggregate
b. Mortar
c. Roofing felt
d. Reinforcing steel
Rationale: Mortar bonds masonry units together, distributes
compressive loads across the joints, and helps seal the wall against
,water and air infiltration. Its composition and properties must be
appropriate for the masonry units and intended application.
2. What is the primary function of Portland cement in masonry
mortar?
a. To provide waterproofing exclusively
b. To replace all fine aggregate
c. To act as a hydraulic binder that contributes to strength and
cohesion
d. To prevent all mortar shrinkage
Rationale: Portland cement reacts chemically with water through
hydration, forming compounds that bind the mortar together and
contribute to strength. Cement alone does not provide all the
necessary properties of mortar, and it does not eliminate shrinkage or
guarantee waterproofing.
3. Which aggregate is most commonly used as the fine aggregate in
masonry mortar?
a. Large crushed granite
b. Pea gravel
c. Steel shot
,d. Clean, properly graded sand
Rationale: Properly graded sand provides the bulk of the mortar,
contributes to dimensional stability, and helps control workability and
shrinkage. Coarse aggregate is generally unsuitable for ordinary
mortar joints because of the limited joint thickness.
4. What is the main purpose of hydrated lime in traditional cement-
lime masonry mortar?
a. To make the mortar set instantaneously
b. To improve workability, water retention, and plasticity
c. To eliminate the need for sand
d. To prevent all efflorescence
Rationale: Hydrated lime improves the plasticity and water-retention
characteristics of mortar, helping masons spread it and maintain good
contact with masonry units. It does not eliminate efflorescence or
make mortar set instantaneously.
5. Which property is especially important when selecting mortar for
soft, historic brick?
a. Maximum possible compressive strength
b. The fastest possible setting time
, c. Compatibility with the brick, including appropriate strength and
flexibility
d. The highest possible cement content
Rationale: Mortar that is excessively strong or rigid can damage softer
historic brick by concentrating stresses and interfering with moisture
movement. Compatible mortar should accommodate movement and
allow the masonry to perform as intended. Historic masonry repairs
often require careful evaluation of the original materials.
6. What is efflorescence on a masonry wall?
a. A structural crack caused by settlement
b. A protective coating applied to brick
c. A type of reinforcing steel corrosion
d. A deposit of soluble salts left on the surface as moisture evaporates
Rationale: Efflorescence occurs when water transports soluble salts
through masonry and deposits them on the surface during
evaporation. It is often a cosmetic issue, although persistent moisture
associated with it may indicate a drainage or water-entry problem.
7. Which masonry unit is manufactured by firing clay or shale in a
kiln?
Questions and Correct Answers
(Verified Answers) Plus Rationale 2027
Q&A| Instant Download Pdf
Section 1: Masonry Materials and Fundamentals
1. Which material is primarily responsible for binding masonry units
together in a conventional brick wall?
a. Coarse aggregate
b. Mortar
c. Roofing felt
d. Reinforcing steel
Rationale: Mortar bonds masonry units together, distributes
compressive loads across the joints, and helps seal the wall against
,water and air infiltration. Its composition and properties must be
appropriate for the masonry units and intended application.
2. What is the primary function of Portland cement in masonry
mortar?
a. To provide waterproofing exclusively
b. To replace all fine aggregate
c. To act as a hydraulic binder that contributes to strength and
cohesion
d. To prevent all mortar shrinkage
Rationale: Portland cement reacts chemically with water through
hydration, forming compounds that bind the mortar together and
contribute to strength. Cement alone does not provide all the
necessary properties of mortar, and it does not eliminate shrinkage or
guarantee waterproofing.
3. Which aggregate is most commonly used as the fine aggregate in
masonry mortar?
a. Large crushed granite
b. Pea gravel
c. Steel shot
,d. Clean, properly graded sand
Rationale: Properly graded sand provides the bulk of the mortar,
contributes to dimensional stability, and helps control workability and
shrinkage. Coarse aggregate is generally unsuitable for ordinary
mortar joints because of the limited joint thickness.
4. What is the main purpose of hydrated lime in traditional cement-
lime masonry mortar?
a. To make the mortar set instantaneously
b. To improve workability, water retention, and plasticity
c. To eliminate the need for sand
d. To prevent all efflorescence
Rationale: Hydrated lime improves the plasticity and water-retention
characteristics of mortar, helping masons spread it and maintain good
contact with masonry units. It does not eliminate efflorescence or
make mortar set instantaneously.
5. Which property is especially important when selecting mortar for
soft, historic brick?
a. Maximum possible compressive strength
b. The fastest possible setting time
, c. Compatibility with the brick, including appropriate strength and
flexibility
d. The highest possible cement content
Rationale: Mortar that is excessively strong or rigid can damage softer
historic brick by concentrating stresses and interfering with moisture
movement. Compatible mortar should accommodate movement and
allow the masonry to perform as intended. Historic masonry repairs
often require careful evaluation of the original materials.
6. What is efflorescence on a masonry wall?
a. A structural crack caused by settlement
b. A protective coating applied to brick
c. A type of reinforcing steel corrosion
d. A deposit of soluble salts left on the surface as moisture evaporates
Rationale: Efflorescence occurs when water transports soluble salts
through masonry and deposits them on the surface during
evaporation. It is often a cosmetic issue, although persistent moisture
associated with it may indicate a drainage or water-entry problem.
7. Which masonry unit is manufactured by firing clay or shale in a
kiln?
