Introduction
It is hard to disagree that, in most cases, one’s repair works cannot wait for ideal circumstances, and there may be a need to use concrete in hot weather. Overall, it is essential to notice that a concrete repair can be made when it is cold or hot outside, but numerous precautious steps should be considered to ensure the efficiency of the performed work. The purpose of this paper is to outline the expected effects of heat on concrete, discuss the essence of hot weather concreting, and then list and explain special techniques for creating the mix design to use when it is hot outside.
The Effects of Temperature on Concrete
Some people may find it confusing that concrete repairs can depend on the weather, so it is important to mention the impact of high temperatures on this composite material. When referring to concrete, it is widely accepted that an ideal window is 40 °F to 60 °F, while hot weather is defined by a temperature higher than 77o F – this is when specific measures are required. The primary problem is that increased air temperatures, low humidity, and direct sunlight speed up the evaporation of the water used to cure and hydrate the cement. This process leads to the appearance of cracks and issues like weakness and shrinkage. Concrete loses its workability and has its setting time decreased. Workers face increases in water demand, plastic shrinkage, and rate of slump loss. As a result, the process itself becomes more challenging, and if specific measures are not taken into consideration when making a concrete repair in hot weather, the final result will not be effective and lasting.
Hot Weather Concreting
Overall, the steps listed further can help avoid the aforementioned issues, make the work of concrete contractors easier and faster, and ensure that there are no irritating on-site challenges or delays. One may agree that the key element in hot weather concreting is to plan and prepare ahead. Another important step is to pay attention to each precautious measure because they are effective only when used together. Thus, the first rule of hot weather concreting is to moisten the wooden forms, subgrade, and reinforcing steel prior to pouring the material to retain the water. As for the subgrade, it should not be muddy but damp, and saturating it twice (in advance and then again right before placing concrete) can have a great effect on the final result. Second, delays should be avoided, and the concrete should be shaded from direct sunlight. It is preferable that all work is carried out either early in the morning or in the evening when the air temperature is lower. Finally, over-vibration (more than fifteen seconds) is not recommended because it can lead to a decrease in strength on the concrete surface.
Special Techniques for Creating the Mix Design
Further, it is also of vital importance to discuss the particular measures that concrete contractors need to keep in mind when mixing concrete in hot weather. What one needs to remember the most is that it is not beneficial to add excessive water to the concrete mix. While it may seem effective to compensate for the quickly evaporating water, such a decision can result in lower strength of the composite material and an increase in shrinkable cracking’s rise. Instead of adding excess water, it can be efficient to use special chemical admixtures that are aimed at achieving longer setting times and better workability. At the same time, adequate amounts of water should still be used when mixing concrete, and in hot weather, the water should be cool. These are the key recommendations for creating the mix design when the air temperature is high, and humidity is low.
Special Techniques During Curing in Hot Weather
The final adjustments to the process in question refer to the curing stage. For example, aliphatic curing compounds or impermeable membranes are an integral tool when working in hot weather. Overall, curing needs to be started as soon as possible, and to make the losses of moisture lower, concrete contractors can use wet coverings. It would be ideal to build a temporary shield from wind and direct sunlight to reduce temperature fluctuations and try to keep the concrete in the most suitable conditions during curing. Noticeably, it is important to ensure continuity in curing – if an extended number of alternative techniques and tools are used, cracking may develop. As a consequence, in hot weather, concrete takes less time to strengthen but it is required from workers to prolong this process to make the final result more lasting and effective.
Conclusion
To draw a conclusion, one may say that working with concrete when the air temperature is high, wind speed is excessive, and humidity is low is challenging but still possible. Numerous precautious measures should be taken into consideration to ensure a good result, and planning ahead is the first step. When creating the mix design, pouring, and then curing concrete, contractors are expected to pay special attention to protecting concrete from wind and direct sunlight, select quality compounds and other tools, and complete all the stages quickly and with enough workforce.