Exam Cheat Sheet · Quick Reference

Arkansas Concrete - Commercial Exam

Arkansas  ·  PSI Services Contractor

Verified, not estimated. Every figure below is drawn from the official exam structure we maintain — question counts, passing standard and topic weighting. Practice questions are grounded in the source law with statute citations. We omit any figure we can't verify rather than guess at it.
Total questions
30
Passing score
70%
Exam time
75 min
Administered by
PSI Services Contractor
Format
Reference materials allowed

Arkansas State Portion 30 questions

Estimating 3 Q · 10%
Layout and Excavation 6 Q · 20%
Formwork 4 Q · 13%
Reinforcing Steel 4 Q · 13%
General Concrete 9 Q · 30%
OSHA Safety 4 Q · 13%

Key Distinctions

Plan viewvsProfile view

Plan view is a bird's-eye overhead view showing the layout of the work area, while profile view is a horizontal cut-away (cross-section) along the alignment showing elevations, grades and depths.

Pipe and Excavation Contracting, Page 105, Chapter 3 introduction, plan view/profile view definitions
Payment bondvsPerformance bond

A payment bond guarantees all bills for labor, equipment and materials are paid and liens discharged; a performance bond guarantees completion of the work.

Pipe and Excavation Contracting, Page 47
Column (ACI 347R)vsWall (ACI 347R)

For applying ACI 347R lateral pressure formulas, a column is a vertical element with no plan dimension larger than 6.5 ft (2 m), while a wall has at least one plan dimension exceeding 6.5 ft (2 m).

Contractor's Guide to Quality Concrete Construction (4th ed.), ACI 347R, Table 5.2 (Book Page 71)
Form ties (safety factor 2:1)vsForm anchors (minimum safety factor 3)

Form ties use a usual 2:1 safety factor (working load limited to one-half ultimate tensile strength), while form anchors into previously placed concrete require a minimum safety factor of 3 including live loads and impact because the concrete may still be 'green'.

Contractor's Guide to Quality Concrete Construction (4th ed.), Page 66
Wheeled backhoevsTrack excavator

A wheeled backhoe has a minimum effective digging cycle of about 10 seconds versus about 15 seconds for a small ¾-yard trackhoe (30 to 40 seconds for larger track excavators); in the book's 1,230-ft job example the track excavator produced 50 LCY/hr vs 29 LCY/hr for the backhoe but its mobilization cost (about 10 percent of total job cost) made it unattractive.

Pipe and Excavation Contracting, Page 168
Dozers (short haul)vsScrapers, loaders/trucks, graders

Average cut-to-fill haul distance selects the equipment: dozers for a short haul, self-loading scrapers for a longer haul, loaders and trucks for long-distance hauling, and graders for very slight cuts and fills.

Pipe and Excavation Contracting, Pages 270-271
Calcium chloride acceleratorvsNon-chloride accelerator

Calcium chloride is an effective set accelerator but promotes corrosion of reinforcing steel (and is not an effective antifreeze, lowering the freezing point only a few degrees), so non-chloride accelerators are the more appropriate choice for steel-reinforced concrete.

Design and Control of Concrete Mixtures, 17th ed., Chapter 6 - Chemical Admixtures for Concrete, Page 129 (16th ed.: Pages 222-223)
Concrete with retarding admixturevsCement without retarder

A retarder delays setting and raises lateral form pressure (chemistry coefficient CC of 1.2 versus 1.0 without retarder) and requires lengthened form-stripping times because strength gain is slower.

Contractor's Guide to Quality Concrete Construction (4th ed.), Pages 72 and 82
Escalation allowancevsContingency allowance

Escalation covers anticipated increases in labor, material and equipment costs between bid submission and performance/payment, while a contingency allowance covers possible problems from uncertain conditions (e.g., no boring logs) and cushions idle equipment rental costs.

Pipe and Excavation Contracting, Page 27
Horizontal scalevsVertical scale (two-scale utility plan)

Utility site plans use two scales; in the example of 1 in. = 40 ft horizontal and 1 in. = 10 ft vertical the horizontal is 4 times (4:1) the vertical, although usually the horizontal scale is ten times the vertical.

Pipe and Excavation Contracting, Page 109
Employer with 10 or fewer employeesvsEmployer with more than 10 employees

Under §1926.35(e)(3), an employer with 10 or fewer employees may communicate the emergency action plan orally and need not maintain a written plan.

OSHA 1926 CFR 29, §1926.35(e)(3)
PPE the employer must pay forvsPPE the employer need not pay for

Per §1926.95(d)(2) the employer is not required to pay for non-specialty safety-toe protective footwear (steel-toe shoes/boots) and non-specialty prescription safety eyewear provided the employer permits them to be worn off the job site; other required PPE remains the employer's duty, and each failure to provide PPE to an employee may be a separate violation.

29 CFR 1926, Subpart E, §1926.95(d)(2)

Key Terms

Competent person OSHA 1926 CFR 29, §1926.32(f), Page 31
Per §1926.32(f), one who is capable of identifying existing and predictable hazards in the surroundings or working conditions that are unsanitary, hazardous or dangerous to employees and who has authorization to take prompt corrective measures to eliminate them; accident prevention programs require frequent and regular inspections of job sites, materials and equipment by competent persons designated by the employer (§1926.20(b)(2)).
Emergency action plan OSHA 1926 CFR 29, §1926.35(b), Page 33
Per §1926.35(b), a plan whose minimum elements are emergency escape procedures, procedures for employees remaining for critical operations, procedures to account for all employees after evacuation, rescue and medical duties, preferred means of reporting emergencies, and names/titles of contact persons — a tool and equipment inventory is not required.
Employer accident prevention responsibility 29 CFR 1926, Subpart C, §1926.20(b)(1)
Per §1926.20(b)(1), it is the employer's responsibility to initiate and maintain such programs as may be necessary to comply with Part 1926, and per §1926.20(b)(4) the employer shall permit only employees qualified by training or experience to operate equipment and machinery.
Safety training and education (§1926.21) 29 CFR 1926, Page 30, §1926.21(b)(2)
The employer shall instruct each employee in the recognition and avoidance of unsafe conditions and the regulations applicable to the work environment (§1926.21(b)(2)), instruct employees handling poisons, caustics and other harmful substances in safe handling, hazards, personal hygiene and protective measures (§1926.21(b)(3)), and instruct employees handling flammable liquids, gases or toxic materials in their safe handling and use (§1926.21(b)(5)).
Insulating equipment inspection (§1926.97) 29 CFR 1926, §1926.97(c)(2)(ii)
Insulating equipment shall be inspected for damage before each day's use and immediately after any incident suspected of causing damage, and insulating gloves shall also be given an air test; rubber insulating blankets must be electrically tested before first issue and every 12 months thereafter, when insulating value is suspect, and after repair.
Stairway/ladder access (§1926.1051(a)) 29 CFR 1926, §1926.1051(a)
A stairway or ladder shall be provided at all personnel points of access where there is a break in elevation of 19 inches (48 cm) or more and no ramp, runway, sloped embankment or personnel hoist is provided.
Expansive soil (IBC 2015 §1803.5.3) IBC 2015 Chapter 18 — Section 1803.5.3 Expansive Soil
Soil classified as expansive when it meets all four listed provisions, the first being a plasticity index of 15 or greater determined per ASTM D4318 (20 is the expansion index threshold of Item 4; 10 percent is the passing-sieve/particle-size criterion).
Lateral sliding resistance (IBC 2015 §1806.3.2) IBC 2015 Chapter 18 — Section 1806.3.2 Lateral Sliding Resistance Limit
For clay, sandy clay, silty clay, clayey silt, silt and sandy silt the resistance is computed from cohesion times contact area and in no case shall exceed one-half the dead load.
Minimum concrete cover (cast against earth) Contractor's Guide to Quality Concrete Construction (4th ed.), Page 100 (Table 6.3)
Per ACI 318 as cited in Table 6.3, concrete cast against and permanently exposed to earth, such as footings, requires a minimum cover of 3 inches (75 mm).
Prescriptive footing (one-story light-frame) Contractor's Guide to Quality Concrete Construction (4th ed.), Page 47 (Table 4.1)
Adapted from 2015 IBC Table 1809.7, a footing supporting one floor of light-frame construction requires a minimum width of 12 inches (300 mm) and minimum thickness of 6 inches (150 mm).
Exposure class w/cm limits (Table 2.5) Contractor's Guide to Quality Concrete Construction (4th ed.), Page 24 (Table 2.5)
Category F3 (freeze-thaw with frequent water plus deicing chemicals) allows a maximum w/cm of 0.40 with minimum 5000 psi; sulfate class S2 (1500–10,000 ppm dissolved sulfate) allows maximum w/cm 0.45 with minimum 4500 psi; class W1 (in contact with water, low permeability required) allows maximum w/cm 0.50 with minimum 4000 psi.
Lateral form pressure variables Contractor's Guide to Quality Concrete Construction (4th ed.), Page 70
The three most important variables influencing the lateral pressure fresh concrete exerts on formwork are concrete temperature, rate of placement, and weight of concrete (normalweight concrete about 150 lb/ft³).
Form tie setback for architectural concrete Contractor's Guide to Quality Concrete Construction (4th ed.), Page 66
Architectural specifications requiring no exposed metal at the surface often require that no metal be left closer than 1-1/2 inches (40 mm) to the concrete surface to avoid rust stains.
Camber Contractor's Guide to Quality Concrete Construction (4th ed.), Page 77
A slight upward curvature intentionally built into a structural element or form to compensate for deflection, shrinkage and creep; the common rule of thumb is 1/4 inch per 10 feet (6 mm per 3 m) of span.
Station number Pipe and Excavation Contracting, Page 111
A survey stake marking showing horizontal distance in multiples of 100 feet, with the figure left of the plus sign indicating hundreds of feet and the figure to the right additional feet (Sta 2+50 = 250 ft from Sta 0+00).
Front end loading (unbalanced bid) Pipe and Excavation Contracting, Pages 36-37
Padding markup onto bid items scheduled early in the project; if the owner reduces the quantity of those padded items the contractor loses the concentrated profit (the example shows a 50% cut in a loaded item dropping overall markup from 20% to 10%).
Mobilization cost Pipe and Excavation Contracting, Page 60
A cost that is sometimes itemized separately on the bid; if it is not, it must be included in the equipment cost calculations — and on small jobs it can be large enough (about 10 percent of total job cost in the book's example) to make a higher-production machine unattractive.
Trench box placement in unstable soil Pipe and Excavation Contracting, Page 174
The bottom of the trench box should sit higher than the pipe — 2 to 3 feet higher is usually enough; too low and pulling the box disturbs bedding and new pipe, and more than 5 feet above the pipe makes the ditch unsafe.
Bar support height tolerance Placing Reinforcing Bars (10th ed.), Chapter 10 — Bar Supports
A variation of plus or minus 1/8 inch from the specified nominal height (base to underside of bar) is the normal construction tolerance for bar supports.
Concrete (mixture proportions) Placing Reinforcing Bars (10th ed.), Chapter 3 — Concrete and Reinforced Concrete - Definitions
A mixture of one part cement, about 1½ to 2½ parts fine aggregate (usually sand), about 3 to 5 parts coarse aggregate (gravel, crushed stone or blast-furnace slag), and clean water.

Formulas to Know

Cubic yards of pipe bedding materialCY = trench length (ft) × trench width (ft) × bedding depth (ft) ÷ 27 (27 cubic feet per cubic yard)
Square yards of filter fabricSY = length (ft) × width (ft) ÷ 9; example: 250 ft × 15 ft = 3,750 SF ÷ 9 ≈ 416 SY
Cut/fill volume of a grid prism (Cross Section Method)Volume = average of the four corner cut/fill depths × prism base area; example: (2.3 + 0.9 + 0.8 + 2.3) averaged = 1.58 ft × 2,500 SF = 3,950 cubic feet
Station distance from starting pointDistance = (number left of plus sign × 100 ft) + number right of plus sign; Sta 2+50 = 250 ft from Sta 0+00
Contraction joint spacing, slab-on-ground (rule of thumb)Spacing in feet = 2-1/2 × slab thickness in inches; example: 6 in. slab → 2-1/2 × 6 = 15 ft
Minimum permitted single strength test (Criteria B)For specified f'c of 5000 psi or less, no single test may fall below f'c by more than 500 psi; example: f'c = 4000 psi → 4000 − 500 = 3500 psi minimum, below which an investigation of structural adequacy is required
Nominal maximum aggregate sizeNot more than one-third the depth of a slab and not more than one-fifth the narrowest dimension of a vertical member; example: 4 in. slab → 4 ÷ 3 ≈ 1-1/3 in. governs over 12 ÷ 5 = 2.4 in.
Formwork camber for deflectionCamber = 1/4 inch per 10 feet (6 mm per 3 m) of span
Form tie allowable working loadSafety factor 2:1 — working load of new ties limited to one-half the ultimate tensile strength (form anchors require a minimum safety factor of 3 including live loads and impact)
Lateral form pressure for high-slump concreteWhen slump exceeds 7 in. (175 mm), CCP = wh (full hydrostatic head) regardless of element type, internal vibration depth or rate of placement; w for normalweight concrete ≈ 150 lb/ft³
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