Red Seal Concrete Finisher Practice Exam

What are the common causes of concrete cracking?

1. Improper painting techniques

2. Water exposure

3. Shrinkage, temperature changes, and improper curing

4. Incorrect mixing ratios

The correct answer is: Shrinkage, temperature changes, and improper curing

Concrete cracking is a well-known issue that can arise from several factors, with shrinkage, temperature changes, and improper curing being among the most prevalent. Shrinkage occurs as concrete dries and loses moisture content, causing the material to naturally contract. This process can lead to tensile stress within the concrete, which, if it exceeds the strength of the material, results in cracking. Temperature changes also play a significant role. As concrete is subjected to high temperatures, it expands; similarly, it contracts when temperatures drop. This continuous expansion and contraction cycle can create internal stresses. If these stresses are not managed properly, they can lead to cracks forming over time. Improper curing techniques can exacerbate these issues. Curing is essential to ensure that concrete maintains adequate moisture and temperature during the hardening process. Insufficient curing can lead to rapid moisture loss, which increases the risk of shrinkage and cracking. Knowing these causes helps in taking preventive measures, such as ensuring proper curing practices, controlling temperature exposure, and accommodating for the natural shrinkage processes in concrete design and placement.