ASVAB Practice Test

Why are spaces placed between slabs of concrete in city sidewalks?

1. Allow for expansion and contraction

2. Improve aesthetic appearance

3. Prevent water seepage

4. Reduce sidewalk maintenance cost

The correct answer is: Allow for expansion and contraction

The correct answer highlights the practical reason for spacing between slabs of concrete in sidewalks, which is to allow for expansion and contraction. Concrete, like many materials, reacts to temperature changes. When it gets hot, the material expands, and in colder temperatures, it contracts. These spaces, often referred to as expansion joints, accommodate this movement and help prevent cracking and damage to the sidewalk. While improving aesthetic appearance can be a consideration in design, it is not the primary reason for leaving gaps between slabs. Similarly, although preventing water seepage can be influenced by the design of sidewalks, the spacing itself is not directly aimed at managing water flow. Cost management is important in construction, but the primary technical function of the spaces directly addresses the physical properties of concrete under varying environmental conditions.