NICET - Highway Construction Inspection Practice Exam

What is the main reason for applying liquid membrane forming compound on concrete?

1. To enhance color

2. To prevent water loss during early curing

3. To create a rough texture

4. To promote quicker setting

The correct answer is: To prevent water loss during early curing

Applying liquid membrane forming compound on concrete is primarily done to prevent water loss during the early curing process. Proper curing is critical for achieving the desired strength and durability of the concrete. When concrete is initially poured, it contains a significant amount of water that is necessary for the hydration process, which allows it to gain strength. If the surface of the concrete loses water too quickly, it can lead to problems such as cracking, scaling, or a weakened structure. The liquid membrane forms a protective layer over the surface that helps retain moisture. This barrier minimizes evaporation by restricting the amount of water that escapes into the atmosphere. By ensuring that adequate moisture is present, the compound contributes to the optimal curing environment necessary for the concrete to solidify properly and achieve its intended performance characteristics. In contrast, enhancing color, creating a rough texture, or promoting quicker setting are not the primary purposes of a liquid membrane forming compound. While coloring agents can be added to concrete for aesthetic purposes, those are separate from the curing process. Similarly, achieving a rough texture can be done through different finishing techniques, and quick setting is typically accomplished using specific fast-setting materials rather than a curing compound.