What action is NOT permissible when placing a concrete slab in hot, windy conditions?

Adding field water for desired consistency is not permissible when placing a concrete slab in hot, windy conditions because it can lead to inconsistencies in the concrete mix. During such challenging conditions, maintaining the correct water-to-cement ratio is crucial for achieving the desired strength and durability of the concrete. If additional water is introduced to adjust the consistency on site, it may inadvertently alter this ratio, leading to an increase in porosity and reduced strength once the concrete cures.

In hot, windy conditions, the risk of rapid evaporation can already be a concern, and any unplanned changes to the mix can exacerbate this problem. The proper addition of water should always be done in a controlled environment before the mixing process occurs, ensuring that the integrity of the mix design is preserved. Other methods, such as keeping mix water cool and aggregates moist, spraying surfaces, or moistening forms and reinforcements, are all strategies to mitigate the effects of temperature and wind on the curing process and maintain the quality of the concrete.