ACI Surface Preparation & Finishing Techniques

Question 1

What is the purpose of surface preparation in concrete finishing?

Accepted Answer

To ensure adhesion and cleanliness

Answer

Surface preparation in concrete finishing is critical to ensure proper adhesion of subsequent coatings, toppings, or repair materials. It involves cleaning the surface, removing contaminants, and sometimes roughening it to create a profile that allows for a strong mechanical bond. This step is essential for the longevity and performance of the finished product.

Question 2

Which tool is commonly used for initial surface leveling?

Accepted Answer

Screed

Answer

A screed is a long, straightedge tool used for the initial leveling and striking off of freshly placed concrete. It removes excess concrete and brings the surface to the desired elevation and flatness, preparing it for subsequent finishing operations like floating and troweling.

Question 3

What does a broom finish provide?

Accepted Answer

Slip resistance

Answer

A broom finish is created by dragging a stiff-bristled broom across the surface of fresh concrete after floating. This process creates a textured, non-slip surface, which is particularly important for exterior concrete slabs like sidewalks, driveways, and ramps to enhance safety, especially when wet.

Question 4

When should final troweling be done?

Accepted Answer

After surface has set slightly

Answer

Final troweling should be performed after the concrete surface has stiffened sufficiently, typically when the bleed water has evaporated and the concrete can support the weight of a finisher without leaving deep indentations. Troweling too early can bring excess water and fine particles to the surface, weakening it, while troweling too late makes it difficult to achieve a smooth finish.

Question 5

What tool is used to create edges on concrete slabs?

Accepted Answer

Edger

Answer

An edger is a specialized tool used to create a smooth, rounded, or beveled edge on concrete slabs. This process helps prevent chipping and spalling of the slab edges, improving both the durability and aesthetic appearance of the concrete. It's typically used after the initial floating.

(ACI) American Concrete Institute Concrete Finisher Practice Test

(ACI) American Concrete Institute Concrete Finisher Practice Test

ACI Surface Preparation & Finishing Techniques