Roads, parking lots, driveways: why concrete?

concrete vs asphalt

Concrete is one of the oldest and most widely used construction materials. An ancient site in northern Israel was discovered in 1982 and was deemed one of the oldest permanent villages ever found. Upon unearthing the settlement, they discovered it had a number of concrete floors. The Pantheon in Rome is another example of ancient concrete construction.

Given its long and robust history, why wouldn’t you choose a material that provides benefits to not only the client, but also the designer and the contractor?

Concrete is a durable beautiful, and affordable building solution. To understand why concrete stands out among the building materials you could use for your next project, we’ve outlined some of its benefits.

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concrete and the environment 

When it’s time to repave or replace your driveway, the most popular choices are concrete and asphalt. While many choose asphalt because it’s more affordable upfront, the two materials are now more competitive in price than ever. It’s also important to look at the long-term benefits rather than just the immediate costs.

When you start to look at the basics of concrete, it becomes clear the upfront cost is one of the only benefits of asphalt. Take a look at some of the benefits of concrete before making your choice.

no emissions or toxins

Concrete consists of naturally occurring materials, produces no emissions and needs no toxic preservatives. Concrete does not release Polycyclic Aromatic Hydrocarbons (PAHs) or Volatile Organic Compounds (VOCs), two pollutants that can have adverse effects on plant growth and the microbial communities in soil. Fortunately, the amount of CO2 produced during manufacturing and when using concrete is relatively small. Concrete actually absorbs CO2 throughout its lifetime, helping to reduce its carbon footprint.

heat islands

The “heat island” effect impacts built-up areas and causes them to become hotter than nearby rural areas. According to the EPA, “The annual mean air temperature of a city with 1 million people or more can be 1.8–5.4°F (1–3°C) warmer than its surroundings. In the evening, the difference can be as high as 22°F (12°C).” This rise in temperature can:

  • Increase summertime peak energy demands.
  • Increase air conditioning costs.
  • Increase air pollution and greenhouse gas emission.
  • Cause heat-related illness.
  • Cause water pollution.

Heat islands are caused when areas are developed with buildings, roads, and other infrastructures that replace open land and vegetation. These paved surfaces attract the sun and heat, absorbing it rather than reflecting it. Tall buildings trap the heat and reduce airflow. Concrete plays a significant role in the reduction of heat islands. Due to its lighter color, concrete absorbs less heat and reflects more light than dark-colored materials, helping it maintain a low surface temperature. Lighter surfaces make such an impact on temperatures that, through LEED programs, incentives are given to buildings that use light-colored roofing and pavements.

“Due to the large area covered by pavements in urban areas (nearly 30–45% of land cover based on an analysis of four geographically diverse cities), they are an important element to consider in heat island mitigation.”

pervious concrete  

Pervious concrete pavement is a unique and effective means to address important environmental issues and support green, sustainable growth. This special type of concrete has a high porosity and allows water to pass directly through, reducing runoff. By capturing stormwater and allowing it to seep into the ground, porous concrete is instrumental in recharging groundwater, reducing stormwater runoff, and meeting U.S. Environmental Protection Agency (EPA) stormwater regulations.

There are numerous benefits of pervious concrete. It:

  • Offers more efficient land use by eliminating the need for retention ponds, swales, and other stormwater management devices.
  • Lowers overall project costs on a first-cost basis.
  • Purifies water by breaking down pollutants and chemicals.
  • Channels more water to tree roots and landscaping so there is less need for watering.
  • Eliminates hydrocarbon pollution caused by asphalt pavement and sealers.
  • Reduces hydroplaning, tire spray, and provides easier access to those in wheelchairs.

lower energy use

Due to many of the above facts, concrete use results in lower energy consumption and costs. In fact, concrete is becoming more and more popular in the building of homes and other structures. Buildings made of concrete see lower heating and cooling bills which can, in turn, make housing costs more affordable. This small decrease in energy use from buildings can have a significant impact on the environment. According to The Concrete Initiative, “Because a large proportion of global CO2 emissions come from buildings and these buildings have long lifetimes, even a relatively small decrease in energy consumption has a significant impact.”

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aesthetics of concrete

As opposed to other commercial building materials, concrete puts you in control of your building’s appearance.

Parking lots and areas within a city or community play a much larger role in that community’s appearance than many might think. According to a report from the American Planning Association, parking lots have the potential to become “huge wastes of bulging, shiny, monstrously colored vegetation 5 feet high.”

Parking lots are necessary but can be unsafe blights on a neighborhood rather than simply serving their purpose. For businesses, they play an important role in making first impressions as they are often the first and last experience a customer will have with a building or business. Your parking lot doesn’t have to be a vast, gray, crumbling ocean of monotony; with concrete, your paved business lot, city lot, or driveway can be transformed to meet the aesthetics of the surrounding areas.

Here are some design options for your concrete driveway or lot that show the versatility of concrete.

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stamped concrete

Once your concrete is placed, it can be stamped to create the look of natural stone, pavers, slate, or flagstone. Stamped concrete lets you achieve the look of more expensive stone options without the investment.

colored and stained concrete

There are a wide variety of colors available for concrete. You can use colors to match other elements around your home or business to create a look that leaves a lasting first impression.

Engraved concrete

Concrete engraving is a great way to update the look of your current paved surface as it’s often done on existing driveways. Add circles, beautiful designs, or engravings on your driveway or lot to recreate the look of brick.

Concrete is a versatile material that can help you create a parking lot or entryway that fits your establishment’s persona or your personal taste. It provides the chance for both architectural expression and structural integrity.

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Concrete Durability and Longevity

Some concrete structures built over 100 years ago, indeed as long ago as the Romans, are still in active service today. While that timeline is not common, on average asphalt lasts 15-30 years, while concrete lasts 20-40 years. Some concrete pavements have required little or no maintenance for over 40 years.

One of the main benefits associated with the durability of concrete is its ability to prevent potholes. While concrete may crack, it will not break into pieces. The secret to concrete durability is the chemical reaction that occurs when the materials are mixed.

CONCRETE's CHEMICAL Reaction

When concrete is mixed, a chemical reaction occurs between the water and cement. This reaction is called hydration and not only holds the materials together but also bonds the aggregate. Asphalt does not have this chemical reaction. This reaction prevents concrete from crumbling, breaking apart, or pitting and prevents the potholes that could become a safety hazard for drivers on the road or patrons using a paved lot.

Concrete is less prone to:

  • Rutting.
  • Cracking.
  • Loss of texture.
  • Potholes.

A lack of rutting is a significant advantage as these grooves can fill with water which will hasten the breakdown of the material.

Concrete Highways

Federally funded studies show that concrete Interstate highways around the U.S. last about 2.5 times longer on average than asphalt Interstate highways. New Minnesota concrete pavement designs are expected to last for 60+ years with minimal maintenance. This means no disruption to routes from road construction and less money spent on upkeep. In a state where the construction season immediately follows winter, this is an appealing prospect. 

There are also new techniques in concrete construction that are expected to extend the life of concrete highways even more.  

Dowel Retrofitting: This retrofitting technique involves cutting slots across pavement joints, inserting bars, patching the slots with fast-track concrete mixes, and then diamond-grinding the road to obtain a smooth surface. Washington is one of the first states to undertake this technique and they expect to extend the life of some of their 30-year-old concrete roads by 10 to 15 years. 

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Concrete safety

A highway filled with potholes, grooves, and cracks is unsafe for those driving on it. In icy conditions, a single bump can send you skidding. The durability of concrete and the fact that it is less prone to wear and tear than concrete makes it the safer choice for roads, highways, and even driveways. Here are a few more ways concrete can provide a safe driving surface. 

concrete improves Traction

Concrete's rigid surface provides better traction than many other materials and new techniques when laying concrete are increasing that traction. 

Tining

Tining is a technique where a steel rake is dragged across a slab of wet concrete producing a macro-texture. This texture improves skid-resistance by providing escape channels for water so it doesn't sit on top of the concrete. Water trapped under a vehicle tire can lead to skidding, this technique keeps water off the concrete. 

Concrete Reduces Noise Pollution

Through the use of appropriate placement and texturing, concrete pavements can also achieve noise levels comparable to those of its major competitors. Tining doesn't only produce superior traction under adverse conditions but can also aid in the control ambient tire noise.

Why is noise pollution a big deal?

  • Noise pollution can cause "Noise Induced Hearing Loss."
  • Exposure to loud noises can raise blood pressure and cause heart disease. 
  • Children who live near noisy airports or roads suffer from stress and low attention levels. 
  • Noise pollution has a negative impact on nearby wildlife. 

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When a road is quiet, it not only helps reduce noise pollution, but it also makes for a more pleasant driving experience. 

Concrete's comparable quietness and superior skid resistance, make it a safer choice for major highways than asphalt. 

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cost of concrete 

Not only is the price of the base material higher (and growing) for asphalt pavements, there are also some inherent costs that few people consider. For example, asphalt has to be repaired and replaced far more frequently than concrete.

Because asphalt is a byproduct of oil, its price fluctuates with the price of oil. Asphalt is created when companies make gasoline and diesel fuel from crude oil. The higher oil prices are, the higher the price of asphalt.

Concrete is made from primarily naturally occurring ingredients (water, rocks, Portland cement). While it does tend to be more expensive than asphalt, that is due to the high demand for a material that provides numerous benefits and can often last almost lifetime in many instances.

Upfront, it’s common to pay more for a concrete parking lot, but for those that choose concrete for roads, maintenance costs have often been reduced by as much as 75%. With each one of these maintenance, repair, and reconstruction cycles, there are energy costs. Those energy costs include:

  • The price of gasoline.
  • The price of diesel fuel.
  • The price of other, oil-based products required to heat the asphalt.
  • The cost to operate construction vehicles.

future costs and demands

Conventional wisdom holds that strong, worldwide demand and domestic capacity issues in North America are driving oil prices increasingly higher. This means there are more high-grade products and fewer low-grade materials, such as asphalt, being extracted from a barrel of oil. This also means that higher oil prices and strong demand could lead to a short supply of asphalt materials in the future.

Today, the costs of asphalt and concrete are comparable, even on an initial cost basis.

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If you’re beginning a paving project and still asking yourself, “Why should I choose concrete?” consider the durability, low impact on the environment, and versatility of creating your road, lot, or driveway out of concrete. Have more questions about concrete? Give us a call. 

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