The Recycled Road

RAP has become a major focus area of environmental stewardship by the United States Department of Transportation (DOT) strategic plan. Recycled hot mix asphalt is commonly referred

Recycled Road Materials
Recycled Road Materials

to as RAP or Reclaimed Asphalt Pavement – RAP is added (at 20-25%) to hot mix asphalt to recycle old materials. This reduces the amount of aggregate and binder needed to produce new hot mix asphalt. The plan is the responsibility for environmental quality shared by all those whose actions affect the environment.

Of course there is a policy in place to keep a balance: The Federal Highway Administration (FHWA) actively promotes the use of recycled pavement and technology to preserve our natural environment, and save money. The recycling process allows for the reuse of road materials and provides the user with a quality product at a reduced cost by recovering the residual asphalt and reincorporating it into another equally quality mix – this technology is made in the construction of highways to maximize equal or improved highway road performance.

The three key requirements for asphalt pavement recycling to be successful is to be:

  1. Cost-effective
  2. Environmentally-responsible
  3. Perform well

Read more about this and the already concrete or in-place recycling tips here:

Black Gold Asphalt and Concrete Recycled Materials page or give us a call at 303-791-8300.

Why is my Driveway Cracking?

Cracks in almost every single driveway will eventually crack when the material it consists of starts to break down and the material separates. Sure this seems okay with a driveway that is a couple of decades old, but it’s puzzling and frustrating when this happens to a newer driveway.

There are ways to prevent and correct these problematic cracks, and make sure your driveway looks like it’s new for quite some time.

Concrete and Asphalt

cracked-concrete
Cracked Concrete Driveway

Let’s face it. Both asphalt and concrete make up most of the material of driveways in the United States. Also the are not immune to cracks from the same classifications of causes. Asphalt, however is usually set as one long undivided surface, and , and both can experience cracks from the same set of causes. However, because asphalt driveways are generally set up as one long, unbroken surface, it is argued that they will crack more easily than concrete surfaces, which have “controlled joints interspersed throughout“. Cracks of a remarkable size take several years to appear.

The Poorly-Constructed Base

Improper installation leads to cracks in driveways – many factors can affect the base and or poorly-constructed subbase. A good subbase is installed from crushed stone.

According to Wikipedia:

Properly curing concrete leads to increased strength and lower permeability and avoids cracking where the surface dries out prematurely. Care must also be taken to avoid freezing or overheating due to the exothermic setting of cement. Improper curing can cause scaling reduced strength, poor abrasion resistance and cracking.
(https://en.wikipedia.org/wiki/Concrete)

Despite what you may have heard, concrete doesn’t dry as it sets, but the opposite is true – damp concrete actually sets better than dry concrete. In order to gain strength, it uses water (hydraulic) and has to have the right mix in curing.

Call us at Black Gold Asphalt to find out more today! In Denver 303-791-8300 and Colorado Springs 719-694-0444.

 

Denver

303-791-8300

 

Colorado Springs

719-694-0444

 

Asphalt vs. Concrete Driveways

When it comes to hard surfaces for driveways and other similar applications you generally have two choices: asphalt or concrete. Even thought both surfaces are similar there are key differences that you should take into account before choosing one or the other.

Some of the considerations you have to take into account when it comes to asphalt vs. concrete are appearance, climate factors, cost and maintenance. Both items have pro and cons. Let’s take a look at both.

Asphalt Pros and Cons

Asphalt is one the most common materials used for driveways and roads. It is also called blacktop for it’s color. It is made from a combination of stone and sand fused together from material left over from the production of gasoline, diesel and kerosene.

Pros of asphalt

    • Relatively cheap (much cheaper than concrete).
    • Preferred in cold climates as it’s less likely to crack and snow removal is easier.
    • Because of its dark color it won’t show stains easily.
    • Repair is easy as it can be repaired or re-layered and does not need to be replaced.
    • Can be tinted.
  • Cons of asphalt
    • Somewhat short lifespan.
    • Maintenance is required every few years as it needs to be resealed.
    • Has an oily texture that softens in heat and sunlight.
    • Has rough edges.

 Concrete Pros and Cons

Concrete is another hard surface material that is commonly used in driveways and other hard surface applications. Cement is mixed with sand and gravel to create concrete.

  • Pros of concrete
    • Lasts a long time, 30-40 years.
    • Low maintenance as it does not need to be resealed, especially in warmer climates.
    • Better in warm climates as it does not soften.
    • Can be colored and scored.
  • Cons of concrete
    • Prone to cracking and is not easy to repair.
    • Salt will damage it.
    • Due to its light color, it stains very easily and shows every color.
    • Cost is very high, even twice as high as asphalt.

 

Asphalt vs. Concrete – Choose One

 

If you are looking for a hard surface application, you are going to have to generally decide between these two. So which one should you choose?

  • Even though concrete lasts somewhat longer, asphalt costs considerably less and gives more value for your money.
  • Concrete will eventually crack, even in warmer climates. Since it really can’t be repaired you may be stuck replacing a concrete surface long before its time, if the cracks are too bad.
  • Asphalt can be tinted and made to look very pleasing, similar to concrete.
  • Asphalt does not show stains as bad as concrete.
  • In areas where it snows, even occasionally, asphalt is easier to deal with.

 

Asphalt vs. Concrete – A Close Call

While both surfaces have good and bad traits to them, in northern New Jersey and the surrounding areas it’s best to choose asphalt. The benefits that asphalt gives you are just a bit better than concrete.

Concrete is not a bad choice by any means and people who use it are generally very happy with it, although it may cause you a few more issues in this area, and it costs more. Asphalt is a great choice, and you surely can’t go wrong by choosing it when you need a driveway or other hard surface applications.

The Deterioration of Asphalt Pavement and its Causes

Asphalt pavement is known for it’s durability and resilience. It’s strengths make it a highly used material for many pavement applications and the preferred material for most state and federal road projects. Like all paved surfaces however, it too is susceptible to deterioration due to the laws of mother nature. Despite the great longevity of a properly laid asphalt pavement, it can be cut short due to poor surface preparation and construction technique or simply long term exposure to the elements.

Let’s take a closer look at what causes deterioration.

Deterioration of constructed asphalt pavement is natural. It’s natural because over time  the materials that make up asphalt begin to break down and become affected by elements such as rain, sunlight and chemicals that come into contact with the pavement surface. The liquid asphalt binder that is the “glue” of the pavement begins to lose it’s natural resistance to water, allowing it to penetrate into and underneath the pavement. Once this happens, the surface can quickly fall prey to a number of different types of deterioration.

Deterioration of asphalt pavements can also be due to factors that go beyond just normal wear and tear causing premature deterioration. The premature deterioration of asphalt pavement is usually due to failures in construction – or human error. This can be due to a number of factors including:

• insufficient or improperly compacted base below the asphalt
• over or under compaction of asphalt
• improper temperature of asphalt when applied
• poor drainage

When asphalt pavement is constructed and maintained properly it wears out slowly and can last up to 25 years or more. Proper maintenance is key to protecting it from the external factors that wear it out. Factors that cause deterioration in pavement include.

Water – over time and especially without proper maintenance water penetrates the asphalt, washes out the base underneath it, causing it to crack, break down and collapse.

Sunlight – Oxidation breaks down and dries out the once flexible liquid asphalt that holds the aggregate together. This causes raveling and shrinking cracks which allow water to penetrate beneath the surface.

Chemical / petroleum exposure – the introduction of chemicals to asphalt, including gas and oil, can soften the asphalt and cause it to break down more rapidly.

The truth is no asphalt is exempt from deterioration no matter how well it is constructed. Asphalt deterioration begins immediately. Even in normal conditions substantial deterioration can begin to take place after 3 to 5 years. It is normal after this amount of time for asphalt to begin to turn gray, become brittle and start cracking. Water begins entering the cracks, freezes and thaws during the yearly cycle and causes larger cracks and potholes. Rain enters the cracks and causes base damage. These all contribute to a worn out asphalt pavement and must be stopped before it’s too late.

Below is a list of the different types of asphalt deterioration caused by the preceding factors:

Cracking – There are many different types of cracking that can occur, and believe it or not they all have names. They include: alligatoring, edge cracks, slippage (caused by improper compaction), reflection (older cracks occurring in a new overlay), edge joint, shrinkage and widening.

Distortion – Caused by improper pavement construction, deterioration of the underlying base or existing asphalt and high load factors, asphalt distortions include: channels or ruts, corrugations and shoving, grade depressions, upheaval and utility cut depressions.

Disintegration – Types of asphalt disintegration includes potholes, raveling, gas and oil spillage.

Just as you paint a new house to protect it from the elements, asphalt must also be protected to maximize its lifespan. Sealing the pavement with a quality asphalt or coal tar based sealant is the best way to protect this valuable investment. In fact, it is recommended that new asphalt be sealed within 60 to 90 days of the application (after it has cured, hardened) to begin protecting it from the elements.

Types of Asphalt Pavement

In addition to being smooth, durable, safe, and quiet, asphalt is the most versatile pavement material. Pavement structures can be designed to handle any load, from passenger cars to heavy trucks. Surface mixes can be customized to absorb noise, to reduce splash and spray during rainstorms, and even to help treat rain water.

Busy commercial airports have main runways surfaced with Asphalt. Asphalt is also used extensively on runways at general aviation airports. Asphalt’s speed of construction makes it an ideal choice for rehabilitation of busy aviation facilities.

At racetracks, asphalt pavements provide smooth driving surfaces combined with the excellent traction demanded by professional stock car racing. Of the 33 NASCAR race tracks across the country, 31 have asphalt surfaces. Of the 88 race tracks listed for the NASCAR Short Track series, 66 are asphalt, 21 are dirt or clay, and 1 is concrete.
Whether on the road, in a parking lot, or at an airport, asphalt pavements add up to the best value for the taxpayer dollar, with the lowest life cycle cost and the highest residual value.

Mix Type Selection

Pavement type selection processes are used by pavement authorities such as state highway agencies to identify the most beneficial type of pavement structure for a given set of traffic, soils, climate, and other factors. They may be as simplistic as specifying a certain type of pavement on the basis of traffic level, or they may be as complicated as assigning weighting factors to more than a dozen characteristics and evaluating the outcome through a scoring system. Whatever process is used, it should be a rational and explainable methodology in which the effects of different variables on decision making may be determined. Information used to develop the process should reflect documented historical performance and cost records.

The 1993 AASHTO Guide for the Design of Pavement Structures, published by the American Association of State Highway and Transportation Officials, outlines the considerations for pavement type selection in its Appendix B. The principal factors to be considered include traffic, soils characteristics, weather, construction considerations, recycling, and cost comparison. The secondary factors include performance of similar pavements in the area, adjacent existing pavements, conservation of materials and energy, and availability of local materials, among other issues.

The Asphalt Pavement Alliance has developed a position paper in order to discuss the primary considerations in pavement type selection as presented in the AASHTO Guide in detail, and to present the advantages available from Hot Mix Asphalt pavements in each of these. Additional considerations include the issue of tire-pavement noise generation, ride quality, and safety, and the advantages asphalt offers in these characteristics.

Perpetual Pavement

Perpetual Pavement combines the well-documented smoothness and safety advantages of asphalt with an advanced, multi-layer paving design process, that with routine maintenance, extends the useful life of a roadway. Pavements designed and constructed in accordance with the Perpetual Pavement concept will last, and last, and last.

How it works

Perpetual Pavements use multiple layers of durable asphalt to produce a safe, smooth, long-lasting road. The pavement design begins with a strong, yet flexible bottom layer that resists tensile strain caused by traffic, and thus stops cracks from forming in the bottom of the pavement. A strong intermediate layer completes the permanent structural portion, and a final layer of rut-resistant HMA yields a surface that lasts many years before scheduled restoration. A Perpetual Pavement provides a durable, safe, smooth, long-lasting roadway without expensive, time-consuming, traffic-disrupting reconstruction or major repair.

Major advantages

When scheduled surface restoration is performed, Perpetual Pavements can be maintained easily and cost-effectively without removing the road structure for reconstruction, saving time and money while keeping motorists happy.

Asphalt is recyclable, providing further cost savings and environmental benefits.

Asphalt has a proven safety record as a driving surface, offering stronger visual contrast with center stripes and other markings. Additional advantages can include reduced noise, reduced splash and spray, and greater skid resistance.

 Porous Asphalt

Porous asphalt pavements offer developers and planners a new tool in their toolbox for managing storm water. These pavements, used mostly for parking lots, allow water to drain through the pavement surface into a stone recharge bed and infiltrate into the soils below the pavement. Such pavements have been proving their worth since the mid-1970s, and recent changes in storm water regulations have prompted many consulting engineers and public works officials to seek information about them.

Quiet Pavement

In the world today, noise has become one of the most pervasive forms of environmental pollution. Noise is everywhere. It affects our lives at home, at work, and at play. Wherever people live there is noise. Noise, by definition, is any unwanted or excessive sound. It can be a nuisance, interfering with sleep, work, or recreation.

There is one type of noise that can be effectively treated at its source: road noise. By paving roads and highways with asphalt, noise experienced both inside and outside homes and businesses can be significantly reduced.

Research in the U.S. and Europe shows that resurfacing a noisy road with stone-matrix asphalt (SMA) or open-graded friction course (OGFC) mix will reduce highway noise by 3 to 5 dB(A) or more. To the average person, this reduction is the same as doubling the distance between the source of the noise and their location.

When comparing the noise reduction that is possible by choosing asphalt pavement, we see how much more practical pavement surface selection is than construction of noise barrier walls.

Warm-Mix Asphalt

Warm-mix asphalt is the generic name of technologies that allow the producers of hot-mix asphalt pavement material to lower the temperatures at which the material is mixed and placed on the road. Reductions of 50 to 100 degrees Fahrenheit have been documented. Such drastic reductions have the obvious benefits of cutting fuel consumption and decreasing the production of greenhouse gases.

Can I Pave in the Winter?

Well, it depends on whether or not the ground is frozen and how cold it is. If the ground is frozen, then the asphalt paving contractor should not be applying the asphalt. If it is applied when the ground is frozen, then it will not roll well. The asphalt is applied very hot, allowing it to roll and spread evenly. If the asphalt is poured on a frozen area, it will stiffen and harden up and will not roll smooth and evenly. If by chance the asphalt doe roll to grade when it is cold out, it will result in a poor quality driveway that does not adhere and will break down and crumble. The material of the asphalt will not be firmly packed and will result in stones quickly becoming loose.

Keep Your Asphalt in Top Condition

Driveway sealing is a great way to protect and prolong the life of your driveway. Asphalt surfaces are very susceptible to deterioration, both from weather and from car use , and the grade of asphalt commonly used on driveways is even more so. Driveway sealing at regularly gives your driveway the protection it needs to have a long life and resist cracking.

Needs Regular Maintenance
If you’re not sure about this, think about the constant maintenance that occurs on the asphalt in your area to stay in good shape. In addition,  the asphalt used on roads is generally a very high grade, make to withstand lots of heavy traffic and you can see why it’s important to keep up on regular maintenance, including asphalt sealing, in order to fend off major projects such as repaving a crumbling asphalt surface.

The Benefits
Sealing your driveway has many benefits when it comes to preserving your concrete driveway. First and foremost, a properly applied driveway sealer repels water, perhaps the single most harmful agent when it comes to deteriorating asphalt surfaces. Concrete has a natural tendency to crack if water is allowed to permeate it, and this tendency is only increased by the weight of cars regularly driving over it. Once those cracks appear, water further damages it, especially in cold climates where it expands and contracts with freezing temperatures.

Other enemies of your driveway include sunlight and oxygen. By regularly applying a quality driveway sealer to your concrete you can prevent water, sunlight, and air from permeating your asphalt and prevent these problems. As an added benefit, driveway sealing also repels oil spills and leaks and makes it much easier for you to sweep and clean your driveway surface.