North Carolina General Contractors Practice Exam

Which of the following factors most affects the drying time of mortar?

1. Type of sand used

2. Humidity levels

3. Temperature of the mix

4. None of the above

The correct answer is: Humidity levels

The drying time of mortar is primarily influenced by humidity levels. High humidity can slow the evaporation of moisture from the mortar, which can extend the drying time considerably. In contrast, lower humidity levels can accelerate the drying process as moisture evaporates more quickly. While factors like the type of sand used and the temperature of the mix can also play a role in the overall setting and curing processes, they have a lesser impact on drying time compared to humidity. The composition and granulometry of the sand may affect the workability and strength of the mortar but will not significantly alter the time it takes to dry. Similarly, while temperature can influence the rate of chemical reactions in the mix, making it set faster or slower, it's the ambient humidity that has the most pronounced effect on the drying duration itself. This makes understanding humidity levels critical for construction projects involving mortar.