Which factor does NOT influence the setting time of concrete?

The setting time of concrete is affected by various environmental and material factors that influence the chemical reactions occurring during the curing process. Among these, humidity, water-cement ratio, and temperature play significant roles.

Humidity affects the evaporation rate of water from the surface of freshly poured concrete. Higher humidity levels can slow down evaporation, thereby prolonging the setting time, while low humidity can lead to quicker evaporation and potentially faster setting times.

The water-cement ratio is crucial because it determines the amount of water available for the hydration process. A lower water-cement ratio generally results in a denser, stronger concrete, but also can lead to longer setting times due to insufficient water for hydration. Conversely, a higher water-cement ratio can expedite the setting process but may lead to weaker concrete.

Temperature directly influences the rate of chemical reactions in concrete. Warmer temperatures accelerate the hydration reactions, leading to quicker setting times, while colder temperatures slow these reactions, resulting in longer setting times.

In contrast, the type of light used does not impact the setting time of concrete. While light can have various effects in some contexts, it does not play a role in the hydration process of concrete as the other factors do. Therefore, the choice regarding the type of light is