CLA CLA Hardscape & Materials

Question 1

What is the recommended minimum thickness for a concrete pedestrian walkway slab in a residential landscape setting?

Accepted Answer

4 inches

Answer

A 4-inch thick concrete slab is standard for residential pedestrian areas; vehicular areas typically require 6 inches or more.

Question 2

Which paving pattern for rectangular brick or concrete pavers provides the greatest interlocking structural strength for vehicular areas?

Accepted Answer

Herringbone (45° or 90°)

Answer

A herringbone pattern creates maximum interlock between pavers, distributing loads laterally and resisting creep under vehicular traffic.

Question 3

What material is a 'geo-grid' used for in landscape and hardscape construction?

Accepted Answer

Soil reinforcement in retaining walls and base courses

Answer

Geogrid is a polymer mesh embedded in soil or aggregate base layers to reinforce retaining walls and stabilize road or pavement base courses.

Question 4

Which type of retaining wall system uses interlocking concrete blocks with no mortar and relies on mass and batter for stability?

Accepted Answer

Segmental retaining wall (SRW)

Answer

Segmental retaining walls (SRWs) use dry-stacked interlocking concrete units that rely on mass, batter (backward lean), and often geogrid reinforcement for stability.

Question 5

What is 'batter' in the context of retaining wall design?

Accepted Answer

The inward lean of a wall face from vertical to improve stability

Answer

Batter is the intentional backward lean of a retaining wall face toward the retained soil, which shifts the wall's center of gravity and improves overturning resistance.

(CLA) Certified Landscape Architect Practice Test

(CLA) Certified Landscape Architect Practice Test

CLA CLA Hardscape & Materials