ACI Decorative Concrete & Stamping 4

Question 1

When using a liquid release agent for stamped concrete, when should it be applied?

Accepted Answer

Sprayed onto the stamp tool and/or slab surface just before stamping

Answer

Liquid release agent is applied to the stamp tools and/or fresh concrete surface immediately before each stamping pass to prevent adhesion.

Question 2

What is the main advantage of using a dry-shake color hardener over integral color in decorative flatwork?

Accepted Answer

It produces a harder, more abrasion-resistant surface with intense surface color

Answer

Dry-shake color hardener densifies the concrete surface layer, increasing wear resistance while delivering vibrant color concentration at the surface where it is most visible.

Question 3

Which of the following is a recommended practice to prevent color fade in sealed stamped concrete exposed to UV light?

Accepted Answer

Select a UV-resistant sealer formulated with UV stabilizers

Answer

UV-resistant sealers contain stabilizers that slow photodegradation of the sealer film and help preserve the underlying color from sun bleaching.

Question 4

What is the purpose of running a chisel or margin trowel along the edge of a stamp pattern near a wall or curb?

Accepted Answer

To define and sharpen the pattern detail where full stamp tools cannot reach

Answer

At edges and tight areas where large stamp mats cannot be fully pressed, hand tools are used to trace and define the pattern detail to match the rest of the slab.

Question 5

What is 'efflorescence' and why is it a concern on decorative concrete?

Accepted Answer

White mineral deposits that migrate to the surface and mar the decorative appearance

Answer

Efflorescence is soluble salt deposits carried to the surface by moisture that, when dry, leave white hazy stains that diminish the look of decorative work.

(ACI) American Concrete Institute Concrete Finisher Practice Test

(ACI) American Concrete Institute Concrete Finisher Practice Test

ACI Decorative Concrete & Stamping 4