Construction Practice of Flexible and Concrete Pavements Including Modern Materials and Methods || Highway Engineering || #18

Construction practice has seen a lot of changes over the years, especially in the field of pavements. Two common types of pavement are flexible pavements and concrete pavements. The former is mainly used for roads with lower traffic volume and is constructed using asphalt concrete, while the latter is used for high-volume roads and airports and is made using Portland cement. This blog post will provide a comprehensive overview of the construction practices of flexible and concrete pavements, including modern materials and methods.

Construction of Flexible Pavements

Flexible pavements are built using asphalt concrete, which is made of a mixture of asphalt and aggregate. This type of pavement is typically found in roads with lower traffic volume. The construction process of flexible pavements is straightforward, and it can be completed within a relatively short time.

The first step in constructing flexible pavements is to prepare the subgrade. The subgrade must be well-compacted, and any organic materials should be removed. This is to ensure that the pavement will have a stable foundation.

Next, the asphalt concrete is laid on the subgrade. The asphalt is heated to a temperature that makes it easier to work with, and it is then spread over the subgrade using an asphalt paver. The aggregate is then spread over the asphalt. The mixture is then compacted using a roller.

In some cases, a second layer of asphalt is added. This layer is usually called the "wear course" and is the layer that will come into direct contact with the tires of vehicles. The wear course is usually made up of a fine aggregate, and it is added to provide a smooth and durable surface for vehicles.

Construction of Concrete Pavements

Concrete pavements are typically used for high-volume roads, airports, and other applications that require a strong and durable pavement. The construction process of concrete pavements is more complex than that of flexible pavements, but it is also more durable and long-lasting.

The first step in constructing concrete pavements is to prepare the subgrade. As with flexible pavements, the subgrade must be well-compacted and free of organic materials. A concrete base course is then added to the subgrade. The base course provides a stable foundation for the concrete pavement and helps to distribute the weight of vehicles evenly over the subgrade.

The next step is to lay the concrete pavement. The concrete is mixed on site and poured into forms. The forms help to shape the pavement and keep it in place until it sets. Once the concrete has set, the forms are removed, and the surface is smoothed.

In some cases, a concrete overlay is added to the surface of the pavement. This overlay provides an extra layer of protection against weathering and wear and tear.

Modern Materials and Methods

In recent years, there have been many advances in the materials and methods used in the construction of pavements. For example, many modern flexible pavements are now made using "warm-mix" asphalt. This type of asphalt is heated to a lower temperature than traditional asphalt, which makes it easier to work with and reduces emissions.

In the case of concrete pavements, advances in materials and methods have made it possible to build more durable and long-lasting pavements. For example, many modern concrete pavements now use "self-consolidating concrete." This type of concrete is designed to flow more easily and fill any voids in the pavement without the need for additional compaction.

Conclusion

In conclusion, the construction of flexible and concrete pavements has come a long way in recent years, and modern materials and methods have made it possible to build stronger, more durable, and more long life.