National Occupational Competency Testing Institute (NOCTI) Carpentry Practice Exam

For what purpose is Sand used in concrete preparation?

1. For aesthetic purposes

2. To enhance strength and durability

3. To promote better curing

4. For thermal insulation

The correct answer is: To enhance strength and durability

Sand is a crucial ingredient in concrete preparation primarily because it enhances the strength and durability of the final product. When mixed with cement and water, sand acts as an aggregate that fills voids and contributes to the overall structural integrity of the concrete. The cohesive properties of sand, when combined with cement, help bind the components together, resulting in a more robust material that can better withstand pressure and environmental factors. In terms of durability, sand helps to ensure that the concrete can resist cracking and shrinkage as it cures, making it essential for long-lasting construction. While sand might have minimal aesthetic implications, its primary role in strengthening concrete is vital for construction projects. Other choices refer to features that are not the main purpose of sand in concrete preparation.