Why Choose Concrete Roads vs Asphalt?

This article will answer the question “Why choose concrete roads vs asphalt?” and will cover topics such as the main difference between concrete and asphalt as a building material. The advantages and disadvantages of using concrete to roadways as well as the pros and cons of asphalt roads will also be elaborated in this blog post.

Why choose concrete roads vs asphalt?

Concrete is considered the best building material for road constructions when the requirement of the project is more durability and resistance against high compressive loading. This means that the road is expected to endure massive and heavy truck and vehicle traffic for a long period of time. In addition, concrete is usually chosen for highways when the project is not limited by any budget constraints. Compared to asphalt, concrete is more expensive and that detail should always be considered when selecting the material for large-scale projects like roads and highways. 

In other words, the selection really depends on the traffic expectation, the available resources, the required strength and durability, and the availability of alternative routes when the construction finally commences.

Concrete vs Asphalt

Concrete is a composite building material whose components are water, cement, and aggregates. The bulk of the mixture is made of high-strength aggregates which are bound together by the cement paste. Concrete mixture undergoes a curing process which is a chemical reaction that enables the structure to gain strength over time. 

This process usually lasts for about a month and requires additional effort during the curing period in order to avoid cracking damages. Plain concrete is innately strong and resistant against compressive stress, but has a very vulnerable stance against tension. For this reason, reinforcements are normally included in the design of the structure.

On the other hand, asphalt is also a composite material whose binder is bitumen. Bitumen is a dark and highly viscous substance that is a byproduct from the distillation of crude oil. Through distillation, petroleum products are separated in terms of weight and volatility wherein lighter substances like gasoline and diesel are separated from the heavier component like bitumen. Apart from being utilized as a binding agent for asphalt, bitumen is also marketed for its adhesive and waterproofing capabilities. 

Unlike concrete, the heavier aggregates of asphalt are not normally mixed with the binding agent before curing. Instead, these coarse solids are laid down the road before being poured with a mixture of bitumen and smaller solid aggregates. Typically, the aggregates used for asphalt mixtures are sand and gravel just like in concrete structures. 

The final mixture is then treated by exposing the bed mixture with a steamroller, creating a flat and relatively smooth road surface. Once the road is completely paved, the bed is cooled to normal atmospheric temperature and is now ready to be passed along by the traffic.

Concrete: Advantages 

The most reliable characteristic of concrete as a building material is its impressive resistance to compressive stress. It can withstand high loads of impact and compaction to a higher extent, so in terms of application in roads and highways, this material is a great option. Heavy traffic from the accumulated loads of trucks and automobiles could match the innate mechanical properties of concrete. While this building material is innately strong in compression, it is important to note that its strength may depend on the quality of its raw materials. More than half of the total volume of a concrete structure is made of aggregate, so the quality and grade of this raw material could significantly affect the integrity of the structure. Same goes with cement and the purity of the water used.

Furthermore, owing to its innate strength, concrete is found to have longer service life compared to its frequent alternative, asphalt. The resistance of concrete against abrasive forces, chemical attacks, and degradation from changing environmental conditions is commendable to reach an acceptable service life of about forty years.

As far as sustainability is concerned, old concrete is recyclable and qualifies to be used as coarse aggregate to a couple projects. The amount of greenhouse gases produced from the production of its raw materials, while still significantly alarming, is less than compared to its asphalt counterpart.

Concrete: Disadvantages

Concrete construction for roads and highways is definitely more expensive compared to asphalt. In construction projects, budget constraint is a great factor in the decision-making process especially when the project is just starting out. Utilizing concrete as a building material is not only expensive in the installation phase but also in maintenance and repair phase.

The repair and maintenance of concrete roads are extremely tedious. The current damages of the structure like cracks and craters cannot typically be addressed by simple patching and resurfacing. Most often than not, especially when the condition is critical and alarming, the overall slab needs to be replaced. Yes, it happens; and creating a new slab doesn’t happen overnight. The preparation of material as well as the curing of the structure last for a long time, so it is expected that a new route is prepared before starting out the repair and maintenance activities.

Asphalt: Advantages 

Compared to concrete, the cost of asphalt construction is significantly less expensive. Its irresistible price point makes it an easy alternative when the economic aspect of the project is lean and requiring budget cuts.

The installation, repair, and maintenance of roadways made from this building material are also easier and less time-consuming than concrete. Creating patches on asphalt roads is not a problem, and it does not require the entire slab to be eradicated and replaced at once. 

Even though asphalt provides a much smoother road surface compared to concrete, it still provides an acceptable and safe skid resistance that avoids unwanted slippage during rainy weather. In addition, because asphalt is black, it has the capacity to absorb light energy from the sun and convert it to heat, allowing assisted removal of moisture.

Asphalt: Disadvantages

Because the binding agent of asphalt is outsourced from crude oil which undergoes a deliberate energy-extensive distillation process to separate fractions of volatile and non-volatile compounds, the amount of greenhouse gases produced to have asphalt as a building material is disastrously affecting the environment. Although asphalt is recyclable, the melting process also releases greenhouse gases to the atmosphere.

The durability and strength of asphalt are not reliable for a long period of time. Generally, asphalt is appropriate for short-term construction projects, and it requires regular maintenance and repair within its functional life.

Conclusion

This blog post answered the question “Why choose concrete roads vs asphalt?”. It was clearly explained in this article that choosing concrete for road construction projects is the best option if the project requires high resistance against heavy loads, more durability or longer service life, and is not constrained by a limited budget. More and more pavements these days utilize asphalt because it is cheaper compared to concrete, but at the end of the day, the decision on selecting the building material depends on the purpose of the project itself.

Furthermore, it was mentioned in this blog post that both concrete and asphalt are similarly structured as a composite material. On the one hand, concrete utilizes cement paste as a binder to its components. On the other hand, asphalt makes use of bitumen as its binding agent.

The article elaborated that the main advantage of concrete is its remarkable strength and durability while its disadvantages include high construction cost as well as more difficult maintenance procedures. Meanwhile, asphalt is seen to be an attractive alternative to concrete because of its cost as well as the east of its construction and maintenance. Although, it is important to note that asphalt is weaker compared to concrete, so it requires regular repair and maintenance.

For any questions and suggestions about this article, please feel free to submit your thoughts in the comment section below.

Frequently Asked Questions (FAQs): Why Choose Concrete Roads vs Asphalt?

Which roads are better concrete or asphalt?

It depends on which side you will be looking at. If you want to consider the strength and durability of the structure, concrete is much better than asphalt in that area. If you need to select based on economic constraint, asphalt is cheaper than concrete. 

Does concrete last longer than asphalt?

Yes, concrete typically lasts twice the service life of asphalt. It is known that the strength and durability of concrete is incomparable to asphalt, so it offers longer functional life.

Why do they use concrete roads?

Concrete structure has innately remarkable compressive strength which means that it can withstand large compressive loads that are normally delivered by large heavy vehicles such as trucks and vans. The amount of vehicles in the road definitely qualifies concrete as a desirable option for road construction projects.

Is concrete used for roads?

Yes, concrete may be used for road construction projects. It offers remarkable compressive strength and durability for a long period of time. Although, commonly, roads are paved using the more inexpensive alternative, asphalt.

Why are American roads made of concrete?

Several American roads are made of concrete because it has high resistance against compressive loads and is durable for a long period of time. It is important to note that some concrete roads are typically paved with the cheaper asphalt. Concrete serves as a strong base for this purpose, and certainly the combination is widely accepted in the construction industry.

 BIBLIOGRAPHY

Henry Gage, S.L., Robertson, J.M., Donnelly, K.C. et al. Qualitative assessment of the mutagenicity of road coating asphalt. Bull. Environ. Contam. Toxicol. 47, 617–622 (1991). https://doi.org/10.1007/BF01700954

Marlof A, Neithalath N, Sell E, et al. The Influence of Aggregate Gradation on the Sound Absorption of Enhanced Porosity Concrete[J]. ACI Materials Journal, 2004,101(1):82–91

Marlof A, Neithalath N, Sell E, et al. The Influence of Aggregate Gradation on the Sound Absorption of Enhanced Porosity Concrete[J]. ACI Materials Journal, 2004,101(1):82–91

Nefedov, B.K., Gorlova, E.E. & Gorlov, E.G. Manufacturing an asphalt-rubber binder for asphalt concrete road pavement via joint thermolysis of crumb rubber with heavy petroleum residues. Soil Fuel Chem. 43, 50–54 (2009). https://doi.org/10.3103/S036152190901011X

Ondova, M., Stevulova, N. Benefits of fly ash utilization in concrete road cover. Theor Found Chem Eng 46, 713–718 (2012). https://doi.org/10.1134/S0040579512060176

Ondova, M., Stevulova, N., and Zelenakova, E., Energy Savings and Environmental Benefits of Fly Ash Utilization as Partial Cement Replacement in the Process of Pavement Building, Chem. Eng. Trans., 2011, vol. 25, p. 297.

Walcave L, Garcia G, Feldman R, Lijinsky W and Shubik P (1971) Skin tumorigenesis in mice by petroleum asphalts and coal-tar pitches of known polynuclear aromatic hydrocarbon content. Tox Appl Pharm 18:41–52.

Yang, Z., Ma, W., Shen, W. et al. The aggregate gradation for the porous concrete pervious road base material. J. Wuhan Univ. Technol.-Mat. Sci. Edit. 23, 391–394 (2008). https://doi.org/10.1007/s11595-007-3391-4

Zhelezko, E.P., Akhmetova, R.S. & Pechenyi, B.G. Service properties of asphalt concretes in relation to asphalt structure. Chem Technol Fuels Oils 10, 192–195 (1974). https://doi.org/10.1007/BF00729301

Leave a Comment