Asphalt plays a major role in road construction. It is a very dense, petroleum-based liquid. Asphalt is black in colour and extremely sticky to the touch. When laying what is called asphalt concrete, road workers use asphalt as the binder. Asphalt concrete is chiefly comprised of crushed gravel, old concrete that has been recycled, and sand. Asphalt is also used to waterproof roofing felt. It is used on flat roofs, such as those designed for sheds and garages.
Depending on the weather
For the most part, asphalt is laid during the hot, dry, summer months. In some cases, however, asphalt can be laid in cooler temperatures. It can also be laid while it is raining. It all depends, however, upon the type of asphalt that is being used by the construction crew. There is a science to laying asphalt. It is vital that certain steps are followed when it comes to laying asphalt in rainy weather.
The most widely used kind of asphalt is termed hot-mix asphalt. This is the type of asphalt that is laid during warm, rain-free weather. Typically, a minimum temperature of 60 degrees Fahrenheit (15.5 C) is required to lay hot-mix asphalt. If it rains, and the skies are cloudy, the temperature drops. This causes hot-mix asphalt to cool rapidly. The result is that it solidifies too soon and becomes unworkable. For that reason, hot-mix asphalt must not be laid during cool, rainy weather.
Aggregate and rain
It is very important that the base materials over which the asphalt is applied are not wet. Collectively, the crushed gravel, recycled concrete, and sand is known as aggregate. If the aggregate has been subjected to heavy rain, it does not mix together in smooth, uniform fashion. Rather, the rain causes hollow pockets to develop in the aggregate. If asphalt is laid over non-uniform aggregate, it will increase the chances of pot-holes developing.
Asphalt and rainy weather
There is one kind of asphalt that, under certain circumstances, can be laid when the weather is rainy. It is termed cold-mix asphalt. Unlike the hot-mix variety, cold-mix asphalt does not require high temperatures to prevent it from solidifying too quickly. Cold-mix asphalt contains a large amount of water. This makes it highly flexible and workable. It can be laid in light rain. If exposed to heavy rain, however, cold-mix asphalt becomes too saturated. Its consistency then breaks down and it becomes unusable. It is, therefore, always advisable to lay asphalt in warm, dry temperatures.