AZ L-87 Shotcrete Contractor Exam
Questions and Correct Answers (Verified
Answers) Plus Rationale 2027 Q&A|
Instant Download Pdf
1. What is the primary purpose of shotcrete in concrete
construction?
a. To replace all structural reinforcement
b. To provide a pneumatically applied concrete or mortar material for
construction, repair, or stabilization
c. To eliminate the need for surface preparation
d. To reduce the need for curing
Answer: b. To provide a pneumatically applied concrete or mortar
material for construction, repair, or stabilization
Rationale: Shotcrete is concrete or mortar conveyed through a hose
and pneumatically projected onto a surface. Its versatility makes it
useful for structural construction, slope stabilization, tunnel support,
,swimming pools, repairs, and other applications. It does not eliminate
reinforcement, surface preparation, or curing requirements.
2. Which two principal methods are commonly used to apply
shotcrete?
a. Gravity feed and immersion
b. Wet-mix and dry-mix
c. Roller-compacted and cast-in-place
d. Precast and prestressed
Answer: b. Wet-mix and dry-mix
Rationale: Wet-mix shotcrete has most or all of the mixing water
incorporated before the material enters the delivery hose. Dry-mix
shotcrete conveys predominantly dry ingredients through the hose,
with water added at the nozzle. Both systems can produce high-
quality shotcrete when properly proportioned, mixed, conveyed, and
applied.
3. In wet-mix shotcrete, when is water generally introduced into the
mixture?
,a. Only after the material reaches the nozzle
b. During batching or mixing before pneumatic delivery
c. After the shotcrete has hardened
d. During final finishing only
Answer: b. During batching or mixing before pneumatic delivery
Rationale: Wet-mix shotcrete is mixed with water before being
pumped through the delivery system. The nozzle primarily controls air
velocity and projection rather than serving as the location where all
mixing water is introduced. Proper water control is important for
strength, workability, and durability.
4. In dry-mix shotcrete, what is primarily adjusted at the nozzle?
a. Aggregate gradation
b. Cement type
c. Water addition
d. Reinforcement spacing
Answer: c. Water addition
Rationale: Dry-mix shotcrete carries the dry ingredients through the
hose, and the nozzle operator introduces and adjusts water at the
nozzle. Proper water control requires experienced nozzle personnel
, because too little water can cause excessive rebound and poor
consolidation, while too much water can reduce quality and
contribute to sagging or excessive shrinkage.
5. What is rebound in shotcrete application?
a. Hardened concrete that expands after curing
b. Material that ricochets or fails to adhere to the receiving surface
during placement
c. Water that evaporates from fresh concrete
d. Reinforcement that moves during shooting
Answer: b. Material that ricochets or fails to adhere to the receiving
surface during placement
Rationale: Rebound consists primarily of aggregate and other
particles that do not become incorporated into the placed shotcrete
and instead bounce away from the surface. Rebound should not
normally be collected and incorporated back into structural shotcrete
because its composition and contamination may be uncontrolled.
6. Which factor has a major effect on rebound?
Questions and Correct Answers (Verified
Answers) Plus Rationale 2027 Q&A|
Instant Download Pdf
1. What is the primary purpose of shotcrete in concrete
construction?
a. To replace all structural reinforcement
b. To provide a pneumatically applied concrete or mortar material for
construction, repair, or stabilization
c. To eliminate the need for surface preparation
d. To reduce the need for curing
Answer: b. To provide a pneumatically applied concrete or mortar
material for construction, repair, or stabilization
Rationale: Shotcrete is concrete or mortar conveyed through a hose
and pneumatically projected onto a surface. Its versatility makes it
useful for structural construction, slope stabilization, tunnel support,
,swimming pools, repairs, and other applications. It does not eliminate
reinforcement, surface preparation, or curing requirements.
2. Which two principal methods are commonly used to apply
shotcrete?
a. Gravity feed and immersion
b. Wet-mix and dry-mix
c. Roller-compacted and cast-in-place
d. Precast and prestressed
Answer: b. Wet-mix and dry-mix
Rationale: Wet-mix shotcrete has most or all of the mixing water
incorporated before the material enters the delivery hose. Dry-mix
shotcrete conveys predominantly dry ingredients through the hose,
with water added at the nozzle. Both systems can produce high-
quality shotcrete when properly proportioned, mixed, conveyed, and
applied.
3. In wet-mix shotcrete, when is water generally introduced into the
mixture?
,a. Only after the material reaches the nozzle
b. During batching or mixing before pneumatic delivery
c. After the shotcrete has hardened
d. During final finishing only
Answer: b. During batching or mixing before pneumatic delivery
Rationale: Wet-mix shotcrete is mixed with water before being
pumped through the delivery system. The nozzle primarily controls air
velocity and projection rather than serving as the location where all
mixing water is introduced. Proper water control is important for
strength, workability, and durability.
4. In dry-mix shotcrete, what is primarily adjusted at the nozzle?
a. Aggregate gradation
b. Cement type
c. Water addition
d. Reinforcement spacing
Answer: c. Water addition
Rationale: Dry-mix shotcrete carries the dry ingredients through the
hose, and the nozzle operator introduces and adjusts water at the
nozzle. Proper water control requires experienced nozzle personnel
, because too little water can cause excessive rebound and poor
consolidation, while too much water can reduce quality and
contribute to sagging or excessive shrinkage.
5. What is rebound in shotcrete application?
a. Hardened concrete that expands after curing
b. Material that ricochets or fails to adhere to the receiving surface
during placement
c. Water that evaporates from fresh concrete
d. Reinforcement that moves during shooting
Answer: b. Material that ricochets or fails to adhere to the receiving
surface during placement
Rationale: Rebound consists primarily of aggregate and other
particles that do not become incorporated into the placed shotcrete
and instead bounce away from the surface. Rebound should not
normally be collected and incorporated back into structural shotcrete
because its composition and contamination may be uncontrolled.
6. Which factor has a major effect on rebound?
