LOUISIANA (LA) HIGHWAY, STREET & BRIDGE CONSTRUCTION PROFESSIONAL CERTIFICATION EXAM QUESTIONS AND FULLY CORRECT ANSWERS

1. Q: What is the minimum compressive strength required for concrete
used in bridge decks in Louisiana? ANSWER 4,000 psi (27.6 MPa) at 28
days
2. Q: What is the standard lane width for Louisiana state highways?
ANSWER 12 feet (3.66 m)
3. Q: What is the minimum thickness for asphalt concrete surface course
on primary highways? ANSWER 1.5 inches (38 mm)
4. Q: What is the maximum allowable moisture content for subgrade soil
compaction? ANSWER Within 2% of optimum moisture content
5. Q: What is the minimum compaction requirement for embankment fill?
ANSWER 95% of Standard Proctor maximum dry density
6. Q: What is the standard superelevation rate for curves on Louisiana
highways? ANSWER Maximum 6% for rural highways, 4% for urban areas
7. Q: What is the minimum clear zone width for a 70 mph highway?
ANSWER 30 feet (9.1 m)
8. Q: What is the maximum gradient allowed for interstate highways in
Louisiana? ANSWER 5% in mountainous terrain, 4% in rolling terrain, 3% in
flat terrain
9. Q: What is the minimum radius for horizontal curves at 55 mph design
speed? ANSWER 1,020 feet (311 m)
10. Q: What is the standard depth for aggregate base course? ANSWER 6
inches (150 mm) minimum
11. Q: What is the maximum allowable deflection for bridge beams under
live load? ANSWER L/800 where L is the span length
12. Q: What is the minimum concrete cover for reinforcing steel in bridge
decks? ANSWER 2.5 inches (64 mm) top, 1 inch (25 mm) bottom

,13. Q: What is the standard width for concrete barriers on bridges?
ANSWER 2 feet (610 mm) at base
14. Q: What is the minimum design life for bridge structures in Louisiana?
ANSWER 75 years
15. Q: What is the maximum water-cement ratio for bridge deck concrete?
ANSWER 0.45
16. Q: What is the minimum curing time for concrete before form
removal? ANSWER 7 days for vertical surfaces, 14 days for horizontal load-
bearing surfaces
17. Q: What is the standard truck loading for bridge design (HL-93)?
ANSWER HS-20 truck plus lane load of 0.64 klf plus 25% impact
18. Q: What is the minimum sight distance for stopping on a 65 mph
highway? ANSWER 645 feet (197 m)
19. Q: What is the maximum allowable settlement for bridge foundations?
ANSWER 1 inch (25 mm) total, 0.5 inch (13 mm) differential
20. Q: What is the standard crown for concrete pavements? ANSWER 1/8
inch per foot (1.04%) from centerline to edge
21. Q: What is the minimum temperature for asphalt paving operations?
ANSWER 40°F (4°C) ambient temperature
22. Q: What is the maximum lift thickness for asphalt concrete placement?
ANSWER 4 inches (100 mm) before compaction
23. Q: What is the minimum overlap for longitudinal construction joints in
asphalt? ANSWER 6 inches (150 mm)
24. Q: What is the standard testing frequency for concrete cylinder breaks?
ANSWER One set per 150 cubic yards or per day of placement
25. Q: What is the minimum age of aggregate stockpiles before use?
ANSWER 48 hours after final placement
26. Q: What is the maximum allowable air content in concrete? ANSWER
6% ± 1.5% for normal exposure
27. Q: What is the minimum width for construction work zones?
ANSWER 12 feet (3.66 m) for through traffic
28. Q: What is the standard height for guardrail installation? ANSWER 31
inches (787 mm) from ground to top of rail

, 29. Q: What is the minimum depth for driven piles in bridge foundations?
ANSWER 20 feet (6.1 m) or to bearing stratum
30. Q: What is the maximum allowable chloride content in concrete mix?
ANSWER 0.15% by weight of cement for reinforced concrete
31. Q: What is the standard frequency for nuclear density testing?
ANSWER Every 500 square yards (418 m²) or as specified
32. Q: What is the minimum temperature for concrete placement?
ANSWER 40°F (4°C) and rising
33. Q: What is the maximum time between concrete mixing and
placement? ANSWER 90 minutes or before initial set
34. Q: What is the standard slope for cut sections in clay soil? ANSWER
1:1 (45 degrees) maximum
35. Q: What is the minimum width for median strips on divided highways?
ANSWER 4 feet (1.2 m) for urban, 26 feet (7.9 m) for rural
36. Q: What is the maximum allowable void ratio in compacted aggregate
base? ANSWER 8% maximum
37. Q: What is the standard frequency for soil density testing? ANSWER
Every 2,000 square feet (186 m²) per lift
38. Q: What is the minimum clearance height for highway overpasses?
ANSWER 16 feet (4.9 m) on interstates, 14 feet (4.3 m) on other routes
39. Q: What is the maximum allowable deviation from design grade?
ANSWER ±0.02 feet (±6 mm) for pavement surfaces
40. Q: What is the standard width for highway shoulders? ANSWER 8 feet
(2.4 m) for rural interstates, 4 feet (1.2 m) for other highways
41. Q: What is the minimum reinforcement ratio for concrete bridge
decks? ANSWER 0.6% of gross concrete area each direction
42. Q: What is the maximum allowable crack width in concrete structures?
ANSWER 0.007 inches (0.18 mm) for severe exposure
43. Q: What is the standard testing temperature for asphalt binder?
ANSWER 77°F (25°C) for penetration testing
44. Q: What is the minimum spacing between expansion joints in concrete
pavements? ANSWER 15 feet (4.6 m) for unreinforced concrete