100+ Free AZ ROC CR-21 Hardscaping & Irrigation Practice Questions

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Key Facts: AZ ROC CR-21 Hardscaping & Irrigation Exam

75 Questions

Official Question Count

PSI Content Outline

180 Minutes

Time Limit

PSI Content Outline

70%

Passing Score

Arizona Registrar of Contractors

$66

Exam Fee

PSI Services LLC

Open Book Computerized MCQ

Exam Format

PSI / AZ ROC Guidelines

100 Questions

Practice Question Bank

OpenExamPrep Practice Bank

The Arizona ROC CR-21 Hardscaping and Irrigation Systems Examination features 75 multiple-choice questions administered in a 180-minute open-book PSI testing session with a 70% passing threshold ($66 exam fee). This practice bank offers 100 high-yield, realistic questions with comprehensive technical explanations, worked hydraulics calculations, ICPI/NCMA guidelines, and code references.

Sample AZ ROC CR-21 Hardscaping & Irrigation Practice Questions

Try these sample questions to test your AZ ROC CR-21 Hardscaping & Irrigation exam readiness. Each question includes a detailed explanation. Start the interactive quiz above for the full 100+ question experience with AI tutoring.

1According to Interlocking Concrete Pavement Institute (ICPI) standards, what is the specified uniform loose, uncompacted thickness for bedding sand beneath concrete pavers prior to compaction?

A.1 inch (25 mm)

B.2 inches (50 mm)

C.1/2 inch (13 mm)

D.3 inches (75 mm)

Explanation: ICPI Tech Spec standards require a uniform nominal bedding sand thickness of 1 inch (25 mm) in a loose, uncompacted state. After pavers are placed and vibrated with a plate compactor, the sand rises into the lower joints while consolidating to approximately 3/4 inch thickness. Excessively thick bedding sand (e.g., 2 inches) leads to severe rutting and uneven settlement under traffic loads.

2Which ASTM material specification is required by ICPI for concrete paver bedding sand?

A.ASTM C33 (washed concrete sand)

B.ASTM C144 (masonry sand)

C.ASTM C330 (lightweight aggregate)

D.ASTM D2940 (graded aggregate base)

Explanation: ICPI requires washed concrete sand meeting ASTM C33 gradation for the bedding layer because its sharp, angular particles provide stability and drainage. ASTM C144 masonry sand contains too many fine particles, which trap water and degrade structural capacity under repeated loading.

3What is the minimum compaction density required for the dense-graded aggregate base layer beneath a residential paver driveway?

A.98% Standard Proctor Density (ASTM D698)

B.85% Standard Proctor Density (ASTM D698)

C.90% Modified Proctor Density (ASTM D1557)

D.75% Relative Density (ASTM D4253)

Explanation: ICPI guidelines specify that aggregate base materials for pedestrian and residential vehicular applications must be compacted to a minimum of 98% Standard Proctor Density per ASTM D698 (or 95% Modified Proctor Density per ASTM D1557). Proper compaction prevents post-construction consolidation, rutting, and paver distress.

4What is the standard recommended compacted aggregate base depth for a pedestrian paver patio versus a residential paver driveway over well-drained subgrade soil?

A.4 to 6 inches for pedestrian; 8 to 12 inches for residential driveway

B.2 inches for pedestrian; 4 inches for residential driveway

C.8 to 10 inches for pedestrian; 16 to 20 inches for residential driveway

D.6 to 8 inches for pedestrian; 6 to 8 inches for residential driveway

Explanation: ICPI Tech Specs recommend a minimum compacted aggregate base thickness of 4 to 6 inches for pedestrian walkways and patios, and 8 to 12 inches for residential driveways on well-drained subgrade. Poorly drained clay soils or freeze-thaw environments require thicker base layers.

5What is the minimum recommended surface slope for a concrete paver installation to ensure positive water drainage away from adjacent structures?

A.3/16 inch per foot (1.5% to 2.0% slope)

B.1/16 inch per foot (0.5% slope)

C.1/2 inch per foot (4.0% slope)

D.3/4 inch per foot (6.0% slope)

Explanation: ICPI guidelines specify a minimum surface slope of 3/16 inch per foot (approximately 1.5% to 2.0%) sloped away from buildings to prevent water pooling on paver surfaces and moisture intrusion into foundations.

6A contractor is preparing a material takeoff for a rectangular driveway measuring 20 feet wide by 40 feet long using standard 4-inch by 8-inch concrete pavers. Including a 10% waste factor for cutting and fitting, how many total pavers must be ordered?

A.3,960 pavers

B.3,600 pavers

C.4,320 pavers

D.2,880 pavers

Explanation: Driveway area = 20 ft x 40 ft = 800 sq ft. Each 4" x 8" paver area = (4/12) x (8/12) = 0.2222 sq ft (or 4.5 pavers per sq ft). Net pavers required = 800 x 4.5 = 3,600 pavers. Adding a 10% waste factor: 3,600 x 1.10 = 3,960 pavers.

7A contractor needs to order ASTM C33 bedding sand for a 1,200 square foot paver patio at a loose thickness of 1 inch. If washed concrete sand weighs approximately 1.4 tons per cubic yard, how many tons of sand should be ordered (rounded to the nearest tenth)?

A.5.2 tons

B.3.7 tons

C.6.8 tons

D.4.4 tons

Explanation: Calculate sand volume in cubic feet: 1,200 sq ft x (1/12) ft = 100 cu ft. Convert to cubic yards: 100 / 27 = 3.7037 cu yd. Multiply by density: 3.7037 cu yd x 1.4 tons/cu yd = 5.185 tons, which rounds to 5.2 tons.

8Per ICPI Tech Spec 2, what is the maximum recommended aspect ratio (Length divided by Thickness) for concrete pavers subjected to vehicular traffic?

A.4:1

B.6:1

C.2:1

D.8:1

Explanation: ICPI Tech Spec 2 mandates that concrete pavers used in vehicular applications have an aspect ratio (Length / Thickness) of 4:1 or less (with a maximum plan area of 100 sq in) to prevent paver cracking under wheel load bending stresses.

9When securing rigid plastic paver edge restraints into a compacted aggregate base, what is the maximum recommended spike spacing along straight runs in dense soil?

A.12 inches

B.24 inches

C.6 inches

D.36 inches

Explanation: ICPI guidelines specify driving 3/8-inch diameter steel spikes (10 to 12 inches long) every 12 inches along straight sections of edge restraint in dense, compacted base material. In loose or sandy soils, spike spacing should be reduced to 8 inches.

10What is the primary function of installing a geotextile separation fabric between fine-grained clay subgrade and the crushed stone aggregate base?

A.To prevent soil fines from migrating up into the aggregate base and preserving load capacity

B.To act as a waterproof barrier that prevents ground moisture from contacting the base

C.To replace the bedding sand layer beneath the pavers

D.To anchor edge restraints without driving metal spikes

Explanation: Geotextile fabric acts as a separation membrane that prevents weak subgrade soil particles (clays/silts) from pumping up into the crushed aggregate base under load, while allowing water to pass through. Soil contamination drastically reduces the structural bearing capacity of the base layer.

About the AZ ROC CR-21 Hardscaping & Irrigation Exam

The Arizona ROC CR-21/C-21/R-21 Hardscaping and Irrigation Systems Examination is a computer-delivered open-book trade exam administered by PSI for the Arizona Registrar of Contractors. The test covers hardscape site preparation, ICPI concrete paver specs, NCMA segmental retaining wall engineering and drainage, irrigation hydraulics, backflow prevention assemblies (RPZ, DCVA, PVB, SVB per ASSE/IPC), automatic control valves and low-voltage electrical systems, and OSHA 1926 trenching/excavation safety standards.

Questions

75 scored questions

Time Limit

180 minutes

Passing Score

70%

Exam Fee

$66 (Arizona ROC / PSI Services LLC)

AZ ROC CR-21 Hardscaping & Irrigation Exam Content Outline

20%

Irrigation Systems

15 of 75 items on the official PSI content outline. Sprinkler and drip design, hydraulics, heads, pipe sizing, valves and backflow protection.

13%

Grading and Drainage

10 of 75 items on the official PSI content outline. Site grading, slopes, surface and subsurface drainage and erosion control.

13%

Low Voltage Electricity

10 of 75 items on the official PSI content outline. Irrigation controllers, valve solenoids, low-voltage wiring, splices and landscape lighting.

Masonry

7 of 75 items on the official PSI content outline. Block and brick hardscape walls, mortar, and unit laying within the classification scope.

Plastering

7 of 75 items on the official PSI content outline. Portland cement plaster and stucco finishes applied to hardscape structures.

Concrete

7 of 75 items on the official PSI content outline. Flatwork, footings, mixes, reinforcement, jointing and curing.

Fences and Retaining Walls

6 of 75 items on the official PSI content outline. Fence layout and posts, and segmental and masonry retaining wall construction.

Rules and Regulations

5 of 75 items on the official PSI content outline. AZ ROC rules, classification scope limits, permits and Arizona 811 blue stake requirements.

General Knowledge

5 of 75 items on the official PSI content outline. Plans, layout, materials and general hardscape trade practice.

Safety

3 of 75 items on the official PSI content outline. OSHA 29 CFR 1926 excavation, trenching, equipment and jobsite safety.

How to Pass the AZ ROC CR-21 Hardscaping & Irrigation Exam

What You Need to Know

Passing score: 70%
Exam length: 75 questions
Time limit: 180 minutes
Exam fee: $66

Keys to Passing

Work through all 100 available questions
Review every answer and explanation
Track weak areas and revisit them
Use our AI tutor for tough concepts

AZ ROC CR-21 Hardscaping & Irrigation Study Tips from Top Performers

1Master irrigation hydraulics: know how to calculate precipitation rate using standard formulas PR = (96.25 x GPM) / Area (sq ft), pipe friction loss, and enforce maximum 5 feet per second flow velocity in PVC/PE pipe.

2Understand backflow assembly rules: PVB (ASSE 1020) must be installed at least 12 inches above highest downstream head/outlet; RPZ (ASSE 1013) is required for high-hazard or chemical/fertilizer injection systems.

3Memorize ICPI concrete paver standards: bedding sand thickness must be 1 inch (25 mm) uncompacted ASTM C33 sand, and sand-set pavers require rigid edge restraints nailed every 12 inches in dense soil or 8 inches in loose soil.

4Review NCMA segmental retaining wall (SRW) rules: gravity walls over 3 to 4 feet generally require engineered geogrid reinforcement, clean open-graded aggregate backfill behind blocks, and continuous 4-inch perforated drain pipe routed to daylight.

5Know OSHA 29 CFR 1926 Subpart P excavation rules: protective systems (sloping, benching, trench box) are required for trenches 5 feet or deeper, ladders spaced within 25 feet of lateral travel for trenches 4 feet or deeper, and Arizona 811 utility markout prior to digging.

Frequently Asked Questions

How many questions are on the official Arizona ROC CR-21 exam?

The official PSI CR-21 content outline lists 75 multiple-choice questions with 180 minutes allowed. PSI publishes the CR-21 content outline in both English and Spanish.

What passing score is required for the AZ ROC CR-21 exam?

A minimum passing score of 70% (53 correct out of 75 questions) is required to pass the trade examination.

Is the Arizona ROC CR-21 Hardscaping & Irrigation exam open book?

Yes, the examination is open book. Candidates may bring approved reference materials into the PSI testing center, including ICPI Tech Specs, NCMA Retaining Wall manuals, Irrigation Association manuals, and OSHA 29 CFR 1926.

What topics carry the highest weight on the exam?

Irrigation Systems is the largest area at 15 of 75 items (20%), followed by Grading and Drainage and Low Voltage Electricity at 10 items each (13%), then Masonry, Plastering and Concrete at 7 items each (9%).

Where can I schedule the AZ ROC CR-21 examination?

Examinations are scheduled online through PSI Services LLC at https://test-takers.psiexams.com/azcon or by calling PSI candidate services.

100+ Free AZ ROC CR-21 Hardscaping & Irrigation Practice Questions

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