ASPHALT PAVEMENT RESEARCH PAPER 30
AsphaltPavement Research Paper
Thispaper highlights possible solutions for the commonly encounteredproblems in asphalt pavements. Asphalt pavement has been the cheapestand easily available option for construction of dependable surfacesfor on-foot pedestrians as well as wheeled traffic all over theworld. Though asphalt pavement is known for its flexibility, theflexibility is pegged on several factors. This flexibility increaseswith temperature, meaning that an asphalt pavement inhigh-temperature areas is likely to move and be distorted under load.A similar pavement in a lower temperature area may hold up the sameload without much distortion.
Themain problem with asphalt pavement is that its quality and lifedepends on both what is done before its construction and itsmaintenance after construction. A surface may be constructed usingthe correct amounts of raw materials and necessary additives but ifit is not maintained well, all these efforts will not amount to much(Ceylan,et al, 2009).Similarly, if the at the point of construction the mixture is notdone in the correct proportions, the resulting surface is prone todistortion regardless of the maintenance efforts that might be put inplace.
However,these two-fold asphalt pavement problem can be addressed well toensure asphalt pavements are safe, cheap and meet customerexpectations. Problems such as cracking, oxidation, raveling and manymore can all be addressed by implementing a preventive strategy earlyenough. Since all the possible problem causes are known, overcomingthese problems only calls for an understanding of them and coming upwith a timely informed solution. The suggestion this paper presentsis that a clear well-thought strategy on how to deal withenvironmental, quality and load issues before, during and aftersurface construction is the ultimate solution to asphalt pavementproblems.
Potholes,shoving, delamination and depression are among asphalt pavementdistresses that are hazardous to motorists. It is not unusual to findvehicles colliding on one way roads while one motorist was navigatinga pothole. Uneven roads as a result of depression and shoving cancause drivers to lose control and cause an accident. These areextreme, but actual problems associated with asphalt pavement.
Wherethere is no accident involved, damaged asphalt surfaces cause cardamages and become an expense to the surface users. In addition,there is an inconvenience on time when one is forced to drive at alower speed by the condition of the road surface. There is also theloss of aesthetic value when a surface is damaged whether it is aroad, a walk path or a parking lot. These reasons warrant researchinto what can be done, and at what time to ensure these problems areavoided or easily addressed when they occur.
Theconventional way of addressing problems once they occur is costly andinconveniencing. Various avenues can be used to avert these problemsinstead of waiting for potholes to show in order to patch thesurface. At that point, the surface will still have lost itsaesthetic value. The best solution is a wholesome approach thatincorporates preventive measures at the design stage, constructionand maintenance phases.
Executive summary 2
1. Problem Statement 4
1.1 Overview of Asphalt Pavement 4
1.2 Types of Asphalt Pavement Mixes 4
1.3 Comparison between Asphalt Pavement and Concrete 7
1.4 Three Top Problems of Asphalt Pavement 8
1.5 Possible Solutions 18
1.6 Proposed Solution 19
1.7 Implications of Collective Effort 22
1.8 Summary 24
1. Problem Statement 1.1Introduction and Analysis
Asphaltis a mixture of an oil component known as bitumen and rock aggregateenhanced with emulsifiers, polymers and cut back agents (AsphaltInstitute, 1997).Therefore, an asphalt pavement is a structure resulting from thismixture being compacted over a base course. A base course is a layerof various sizes of gravel that are meant to interlock and providesupport to the asphalt surface. The mixture may vary depending on thesurface being constructed, environmental reasons or expected loads,but the basic foundation of an asphalt surface lying over a basecourse remains (Stroup-Gardiner,et al, 2000).
Whatthe government or a private constructor is looking for whileselecting a pavement method is cost effectiveness, long life, andsustainability. The surface user expects a smooth, quiet, safe, anduser-friendly surface. Asphalt pavements are capable of deliveringall these qualities to meet customer expectations. This makes asphaltpavement the most desirable pavement because of its versatility(Ceylan,et al, 2009).
Typesof asphalt pavement mixes
Variationsin mixtures include hot mix, warm mix, cold mix, cut-back, mastic andnatural asphalt (AsphaltInstitute, 1997).Each is used for a different surface or function. Various asphaltmixtures deliver different surfaces and performance characteristicssuch as braking efficiency, tire noise, and surface durability (Lee,et al 2006).
Theyare named so because the aggregate used to formulate the mix is notheated or dried in the process of producing this asphalt mixture(Lee,et al 2006).In cold mixes, a cutback asphalt or an asphalt emulsion is used as abinder to the mineral aggregate in the cold mix asphalt mixture. Thecold mix is prepared at ambient temperature. Cold mix asphalt iscommonly used as patching material or for construction of pavementswith less traffic (AsphaltInstitute, 1997).
Tomake hot mix asphalt, aggregates of different sizes are mixed withasphalt cement in a mixing plant at temperatures ranging between 120ºC and 160 ºC (White,2002).Once the aggregates and the hot asphalt cement have blendedperfectly, the mixture is channeled to trucks which then haul it intomechanical spreaders. The workability of hot mix asphalt depends onheat (UnitedStates, 1991).Therefore, it must be compacted before the temperatures cool to below85 ºC to 65 ºC. Hot mix asphalt commonly abbreviated as HMAC, isideal for high traffic driveways such as highways, racetracks, andairfields (Stroup-Gardiner,et al, 2000).
Producingwarm mix requires heat as well. However, the distinction between warmand hot mix is that warm mix requires much lower temperatures duringmixing and laying (UnitedStates, 1991).Zeolites, wax, asphalt emulsions, and even water are added to theasphalt binder before being placed in the mixing plant(Stroup-Gardiner,et al, 2000).The fact that warm mix requires lower temperatures means that it usesless fossil fuels in the production and laying process (AsphaltInstitute, 1997).Less usage of fossil fuel also translates into less carbon dioxide,vapor and other aerosols (Lee,et al 2006).This aspect of environmental friendliness has made the production andusage of warm mix escalate because it suffices for most of thesurfaces that require hot mix. (Stroup-Gardiner,et al, 2000)
Comparisonwith other pavement options
Pavingcan be done using different methodologies that utilize varying rawmaterials. The cheapest is gravel and on the high end of the scalestands brick pavements. However, the two most commonly used pavingmaterial is concrete and asphalt (Ceylan,et al, 2009).Concrete loses the battle to asphalt because asphalt pavements areless expensive to install than concrete pavements. Although concretepavements are more durable than asphalt ones, repairing asphaltsurfaces is far easier than repairing a concrete surface.
Asphaltpavements also deal better with weather changes than concretepavements do (Ruth& American Society for Testing and Materials, 1985).Asphalt surfaces can expand and shrink with changes in temperaturewhile concrete surfaces simply crack under extreme pressure (AsphaltInstitute, 1997).The difference in cost of material averages between 7USD to 10USD persquare foot, with asphalt being the cheaper option (Ceylan,et al, 2009).
Thiseconomic bargain causes individuals, cities and states to chooseasphalt for various surfaces. There are additional advantagesincluding the fact that one can use an asphalt driveway immediatelyafter installation as opposed to a concrete one where one has to waitfor seven days. Asphalt pavements also have greater brakingefficiency than concrete surfaces (AsphaltInstitute, 1997).
Toolsand equipment used in asphalt pavement
Asphaltpavement like any other paving exercise is an equipment intensiveprocess. Besides the general equipment needed for paving such asmaterial-hauling trucks, there are certain equipment specific forasphalt handling. The paver is a massive machine that is used tospread asphalt on the surface being installed (Asphalt Institute,1997). The paver has a heating chamber so as to keep the scree hot.It is also installed with an auger that keeps churning the materialas it goes into the channel.
Thechannel leads to a hopper at the front of the road paver. Thematerial is spread in a wide line by the hopper, and the weight ofthe paver passes over it thus flattening it. The road crew followsbehind shortly after this process to inspect the work and identifyany spots that need correction.
Rollersvary in size and design. There are steel wheel, vibratory andpneumatic rollers (Asphalt Institute, 1997). They are compactiondevices, usually with a drum or two that are driven over HMA.Sometimes the drums are filled with sand or water to add on theirweight, which increases their compaction effort. Asphalt bindersticks on steel wheels. To avoid this, steel wheel rollers aresprayed with water, both at the wheels and the drums to prevent HMAfrom sticking. However, this measure has a negative effect since thewater lowers the temperature of HMA thus reducing the time availablefor compaction (Ceylan, et al, 2009).
Millingmachines are the primary way of removing old HMA on a damaged asphaltpavement to give way for an overlay (Asphalt Institute, 1997). Incase the subgrade of the pavement being replaced is dirt or gravel,graders are used instead of milling machines because graders’blades have a larger surface area to pick up asphalt (Hopper &Smith, 2007).
Batchplants are chambers where asphalt ingredients are placed and heatedto produce HMA in individual batches (Asphalt Institute, 1997). Onebatch can produce 1.5 to 5 tons of HMA within a minute. Drum plants,which became popular in the 1970’s, produce HMA in a continuousmanner (Hopper & Smith, 2007). Depending on drum design, they canproduce up to 900tons per hour. This makes drum plants more efficientthan batch plants and lower in cost as well (Ceylan, et al, 2009).
Asphaltpaving also requires sweepers, which are trucks fitted with partsthat clean the road surface ahead of the overlay (Asphalt Institute,1997). Cleaning the surface is necessary in order to remove large andsmall debris, and also dust. Large debris can cause non-uniformity,while excessive debris and dust can reduce the adhesiveness betweenthe base course and the asphalt (Hopper & Smith, 2007).
Thethree top problems of asphalt pavement
Pavementsare designed in consideration of the geographical location and theprevailing weather conditions in that area. There are certain asphaltpavement damages that are directly attributable to environmentalfactors.
Potholesare noted to form mostly in late winter and early spring. This is asa result of the freeze thaw cycles that characterize this season. Icemelts during the day and settles in cracks small holes on thepavement (Ruth& American Society for Testing and Materials, 1985).At night there are lower temperatures that cause the snow and ice tofreeze. The force exerted by frozen ice is great enough to fractureasphalt. Pieces of asphalt break away, and ultimately a potholeforms.
Potholescan be caused by a thin asphalt surface, poor soils, poor pavementmaintenance, poor compaction or poor drainage (Martono,2008).An area with alligator cracks can become a pothole overnight.
Overtime, an asphalt pavement loses its black color and takes on a grayappearance. This is as a result of oxidation (Martono,2008).Asphalt has an oil component (bitumen). Ultraviolet (UV) radiationaccelerates the rate at which asphalt reacts with oxygen at amolecular level.
Whenthe oil suffers accelerated oxidation, its glue-like characteristicsdiminish continually. Since the binder is no longer able to hold therock, sand and aggregates together, it gives way for further damagessuch as raveling. Oxidation also causes the color of asphalt to fadefrom black to gray.
Treeroots grow to the surface in search of moisture. If the potential ofthe roots growth was carefully considered at the time of the pavementinstallation, the roots are likely to wreak havoc by creating crackson the surface (Martono,2008).
Waterhas effects both from the surface and underground. From the surface,heavy water flow pulls fine aggregates through friction of theflowing water, and ends up eroding the surface over time. Water witha PH higher than 7 has the capability to break down asphalt moleculesinto smaller pieces, which reduces its adhesive qualities paving wayfor other damages (Ruth& American Society for Testing and Materials, 1985).
Undergroundwater causes damage to the base course reducing its ability tosupport the pavement (Ruth& American Society for Testing and Materials, 1985).This structural damage of the foundation means that the pavement’sability to carry traffic and their loads reduces. It makes thepavement prone to cracks, potholes and other damages related toexcess pressure.
Mostof the damages asphalt surfaces face can be addressed adequately byproper design and maintenance (Ceylan,et al, 2009).This places a huge bulk of responsibility on the construction andmaintenance. A typical asphalt pavement should last between 15-20years before getting damage, as long as it was properly designed forits location, and factors such as drainage and car loads have beenmanaged (AsphaltInstitute, 1997).Therefore, extreme damages occurring before the stipulated life timeputs the expertise of the construction company into question.
Surface age and usage
Naturally,an asphalt surface is likely to become prone to damage with thepassage of time. The reason is that with the passage of time comesexposure to various factors that exhaust its useful life gradually(Hopper& Smith, 2007).Each surface is installed with an abstract traffic load capacity. Ifthis capacity is exceeded continually, the surface will suffer theexcess use and show signs of overuse eventually. Besides age, thereare other factors related to usage that contribute to the damage ofasphalt pavements (Martono,2008).
Heavyvehicles have a higher Equivalent Single Axle Loads (ESALs) thanlight weight cars. Interestingly, the relationship between avehicle’s weight and its impact on asphalt is exponential notlinear (Ceylan,et al, 2009).For instance, a typical car has 0.0006ESALs while a garbage ordelivery truck has 1.4ESALs. Translated into the impact on asphalt,the truck has the effect of 2000 cars or more! The truck causesfurther damage by travelling slowly, which happens as the truck slowsdown in the collection and drop off areas.
Oilspillages are especially common in parking areas. When otherderivatives of crude oil besides bitumen come into contact withasphalt, they cause it to break down since its molecular structure isrelatively weak (Martono,2008).The molecules become unchained pieces that can no longer hold therocks together effectively.
Mostasphalt pavement damages are not attributable to one precise factor.Rather, they are hybrid problems where a contributing factor (such asa heavy truck) found a vulnerable surface that is compromised byanother factor (such as underground water damage) (Ceylan,et al, 2009).In other cases, the construction company fails to do a comprehensivestudy of the region and end up installing a surface thatenvironmental factors are going to gnaw away easily.
Hereare the most common asphalt pavement damages caused by a hybrid offactors:
Crackingis commonly caused by exceeding the load limits the surface wasdesigned for (Ceylan,et al, 2009).They can also be caused by improper installation of the base courseand compaction during the initial construction of the surface. Waterpenetration can also cause cracks because it causes softening of theasphalt components making them disintegrate (Ruth& American Society for Testing and Materials, 1985).
Coldtemperatures cause asphalt to crack when it contracts, while hightemperatures soften the asphalt binder giving way for heavy loadscause ruts on the pavement. There are various types of cracks, eachtype related to a certain factor. Crackscould be an indication of several factors. It could be that thepavement laid was thinner than what was required, the pavementmaterial were of poor quality, poor drainage or excess traffic loadthan what the pavement was designed for (Martono,2008).
Repeated traffic overloads cause fatigue failure on the asphalt pavement (Martono, 2008). Large deflections that take place under heavy traffic cause the pavement to bend and unbend until it ultimately cracks. The resultant cracks are interconnected to form a pattern that resembles a wire mesh or an alligator’s skin.
Transverse cracks are principally perpendicular to the pavement centerline (Martono, 2008). The most probable cause of transverse cracking is thermal expansion and contraction. When the pavement contracts due to low temperatures, asphalt is unable to relieve the stress, and it cracks. The ability of a pavement to withstand thermal cycling purely depends on the asphalt properties.
Ruts are longitudinal depressions on the pavement (White, 2002). They develop mostly long the wheel path and are associated with transverse displacement of the flexible pavement aggregates.
Shoving is a longitudinal displacement of an exact area on the asphalt pavement (Martono, 2008). This displacement results in corrugations that look like ripples across the pavement surface. It is mostly found on curved points of the pavement, hills or intersections (White, 2002). It occurs as a result of braking or acceleration by vehicles.
This is when a large area of the pavement surface is lost and the separation between the pavement surface and the layer below is clear (Martono, 2008). Delamination may occur as a result of poor bonding between the adhesive layers. When water gets between the base and the pavement surface, the bond between the overlay and the base course is broken (Ruth & American Society for Testing and Materials, 1985).
This occurs when the surface of high-quality hot mix asphalt wears away progressively (White, 2002). This could happen as a result of dislodging of the asphalt aggregates or loss of the adhesive binder as a result of the effect of unfavorable environmental factors (Martono, 2008). Raveling is caused by the presence of air voids in the HMAC, which could be a result of poor compaction or late season paving.
Bleeding, also known as flushing, happens when asphalt moves to the surface of the pavement (Martono, 2008). As a result, the surface becomes black, smooth, and has a shiny appearance. In hot weather, the bleeding surface is sticky. When wet, the bleeding surface becomes very smooth and slippery and becomes a serious hazard because it occurs along the wheel paths, which means a vehicle can skid very easily.
Sometimes utility lines that lie below a pavement surface need to be repaired, or a new line needs to pass across a pavement (Martono, 2008). Either of the situation causes the pavement to be cut out and repaired after the utility issue has been sorted. Depending on how well the utility cut is repaired, that point could become a point of weakness on that pavement.
Typically, damages on asphalt pavements are handles as they come. This means giving each problem an individualized solution. For instance, for the above-named damages, the solutions would be as follows:
Repairing cracks and small potholes early enough before they cave in. Patching already formed potholes
Apply layers of sealcoat to protect the surface from UV light depending on exposure pavement dressing
Cutting roots and filling up damaged areas on the surface. In some cases, a phased tree cutting program may be carried out.
Sealing the surface to prevent damage from alkaline water and enhancing drainage to handle heavy rain water flow (Ruth & American Society for Testing and Materials, 1985).
Fill up cracks to prevent further damage
Seal the area with an oil spot treatment, preferably latex-based because latex does not dissolve easily.
Sealing cracks to prevent them from expanding
Rutting, shoving and delamination
The best treatment for these damages is to cut out the damaged portion of the pavement and pave it afresh micro surfacing fog or chip seals.
Seal coating for small damage patching for extensive damage.
Applying sand on flushed areas removing excess asphalt using a milling machine using high-float emulsion in the initial paving
The Proposed Solution
The solutions highlighted above are to a large extent reactive measures. The implication is that a lot of damages will have been incurred by the time these remedies are being implemented. The proposed solution is a comprehensive address of all the asphalt pavement possible distresses. It is a proactive engagement process involving all the stakeholders at every point of the asphalt pavement design, installation and maintenance process.
The advantage of a proactive approach to dealing with asphalt pavement problems is that most of the damages can be foreseen and averted (Ceylan, et al, 2009). Therefore, an individual, city or state will end up saving a lot on maintenance costs, and the inconveniences caused in the process of repairing the damaged surface.
Often, a damage will exhibit the contributions of the quality of construction material, environmental factors, and traffic loads. The proposed proactive approach begins with the work of designers. This involves measuring traffic to determine the expected traffic load on the prospective surface. They should pay distinctive attention to trucks and buses because of their exponential Equivalent Single Axle Loads capacity (Ceylan, et al, 2009).
The second step is to examine the subsoil. The soil properties to look out for include permeability, plasticity, frost susceptibility and capillarity. This will be helpful to determine how much load the surface can withstand and how much the pavement thickness should be. The designers will determine whether the pavement needs geogrids to reinforce the base course in order to withstand the expected weight load. The pavement will be designed with those elements in mind.
The design work should deliver three aspects to be actualized by the construction company. The first is the assurance of stability. If the prospective pavement is a repair or upgrade of an existing one, the design objective will be to strengthen the existing base and subgrade. In case of a new pavement, the design should target a stable base and sufficient sub base layers. Apart from engineers, architects and landscapers, the design team should also have an arborist (Hopper & Smith, 2007). The arborist provides expertise on the best way to handle the trees and other plantation that may exist along the pavement.
The second design goal would be to provide adequate drainage both for rain water and below the surface water (Ruth & American Society for Testing and Materials, 1985). This is to ensure all water flow is properly channeled off the pavement to avoid weakening the pavement. The third design objective would be to specify the expected traffic load and the time the pavement is expected to last if these traffic load limit is observed strictly.
The construction company’s objective will be to deliver a pavement that corresponds exactly with the design provided (Hopper & Smith, 2007). It is their responsibility to determine ensure proper mixing of the asphalt mixture and ensuring that they conduct the appropriate compaction for that mixture (Lee, et al 2006). Also, their timing for compaction should be correct to avoid thermal cracks soon after the pavement is completed.
Once the pavement is completed, responsibility shifts to the entity responsible for maintenance. This phase takes a longer time than the other two. Therefore, the entity responsible should be well informed and equipped to take care of the pavement handed over to it by the design and construction team. To attain their objective of keeping the pavement in good condition, the pavement maintenance team will need to assess the state of the pavement continuously.
To be timely in preventing damages and correcting them at an early stage, the maintenance team needs to have reliable means of assessing the pavement condition (Lee, et al 2006). There is sufficient technology that can be used to complement mechanical methods of assessment (Ceylan, et al, 2009). Technology such as sophisticated cameras with software that record the condition of a pavement from miles away can be used together with conventional heavy weight deflectometer to deliver a reliable assessment (International Civil and Infrastructure Engineering Conference, et al, 2013).
The maintenance team should take action based on the results from the assessment. There are four pavement treatments, which are a mix of proactive and reactive measures that the maintenance team should have on their schedule. The first is preventive maintenance. This treatment is primarily for minor defects and is intended to prevent the pavement from deteriorating further. Preventive maintenance does not have the capacity to add structural strength. Rather, it is only meant to improve the surface for ease of use(Hopper & Smith, 2007).
The second treatment is corrective maintenance. This treatment goes beyond correcting existing defects to addressing deficiencies in the original overlay (Hopper & Smith, 2007). It could involve changing the original pavement course from say 1 to 1 ½ inches. Hot in-place asphalt recycling, and mill and fill overlays are other examples of corrective maintenance (Symposium on Quality Management & Decker, 2011).
The third treatment is pavement rehabilitation. Pavement rehabilitation primarily intends to address serious pavement failures (Hopper & Smith, 2007). The treatment is expected to restore a condition that guarantees the pavement a normal useful life of between 10 to 20 years when maintained normally. The fourth treatment, pavement reconstruction, is essentially beginning to rebuild the pavement from scratch (Hopper & Smith, 2007). This is usually warranted when the pavement has depreciated to such an extent that it is no longer usable, and assessment suggests that all the other treatment methods are not cost effective for that case.
Implications of collective effort
As earlier discussed, the reason asphalt is a popular option is because of its cost friendliness and its ease of maintenance. However, when it is plagued by all the distresses outlined, bleeding, cracking, rutting and so on, the cumulative cost of maintenance may beat the logic of choosing asphalt on economic grounds. This cost effectiveness argument needs to be defended. Apart from cost, all the stakeholders from the pavement users to the funding entity be it the city, state or individual need to be satisfied. The only way to gratify them is by delivering a pavement of high quality, sustainable, and with aesthetic value (International Civil and Infrastructure Engineering Conference, et al, 2013).
When responsibilities for the various phases of the asphalt pavement construction are segregated, chances of achieving the goals of cost friendliness, quality and sustainability all at once decrease. When the entire process is aforethought, it is easy to link the design, construction and maintenance team to achieve the desired result. The proposed solution, therefore, is an Integration of a business concept in this vastly mechanical field.
The concept of strategic planning is beneficial in diverse fields and is almost indispensable in any project that has a cost consideration. The ideal solution to make work easier would be to consult a company that has the capability to offer all the services of the various pavement installation and maintenance phases (International Civil and Infrastructure Engineering Conference, et al, 2013). Usually, a paving project involves a paving contractor, material supplier, and an inspection authority.
Since collaboration of all the entities involved in the various phases has been found to be paramount for the achievement of the three goals, it would be perfect if one would find one entity that does it all. That would ensure seamless transitions from the design phase to actual construction. As for maintenance, it is easy to take care of a structure that one constructed as opposed to one merely handed down to them.
The process begins with the company or individual in need of an asphalt pavement presenting clear and precise specifications about the structure they need. With these specifications, the entity can go ahead and call for companies to bid for the paving materials, the paving work or both. Once the bid has been awarded, the owner should call a pre-paving meeting (Symposium on Quality Management & Decker, 2011). This is to make sure each party understands their responsibility. It is also to ensure that everyone is familiar with equipment, materials and procedures to be used in the process.
Before actual paving begins, samples of all the aggregates that intend to be used by for the pavement should be analyzed (Symposium on Quality Management & Decker, 2011). The samples should conform to the mix provided by the design contractor. An inspection should also be done on all equipment to ensure they are in good form, and that they are properly calibrated. Also, soil samples with gradation certificates for the paving area should be produced for examination (Symposium on Quality Management & Decker, 2011).
During construction, random samples should be taken from the aggregate and analyzed to check for consistency with design and specifications (Symposium on Quality Management & Decker, 2011). Loads of asphalt emulsion should be sampled every day and analyzed. The owner should be closely involved in this process to guarantee its authenticity. The analyzed samples should be labeled and stored well for the owner external inspectors to review.
Asphalt pavement has been used extensively in all sorts of surfaces from domestic driveways to airfields. Asphalt pavements can indeed guarantee both cost effectiveness and quality (Symposium on Quality Management & Decker, 2011). All that is needed for the goals to be met is good management of the paving process. One even has the option of consulting with pavement experts before undertaking the project.
For instance, the Asphalt Pavement Association is a consortium of pavement professionals qualified and with a wealth of experience. Such is an opportune group that a pavement owner, designer, engineer or inspector can contact at any stage of the paving process for guidelines and benchmarks.
To support the overall cost effectiveness of asphalt pavement is the fact that almost 100% of asphalt concrete is recyclable (International Civil and Infrastructure Engineering Conference, et al, 2013). This explains why the asphalt raw materials are more affordable than concrete and other paving raw materials. Recycling can be done either on large scale or on an on-site small scale. Recycled asphalt is considered very effective for patching potholes and utility cuts (International Civil and Infrastructure Engineering Conference, et al, 2013).
Once priority shifts from preventive to proactive pavement management system, full benefits of asphalt pavement are realized. The quality of a pavement can be enhanced, and its life can be prolonged by a good design, and appropriate construction and maintenance procedures (Ceylan, et al, 2009). The cost of maintaining a road in good condition is far less than that of repairing it once it breaks down. Proactive plans are therefore delivering value to both owners and pavement contactors.
Since the things that take a toll on asphalt pavement are known, mainly harsh weather conditions, and heavy traffic, efforts have been made over time to mitigate such effects (Ceylan, et al, 2009). One of the results of such efforts is the development of porous asphalt. Porous asphalt has been widely used in construction of parking lots because it allows water to through the asphalt pavement naturally (International Civil and Infrastructure Engineering Conference, et al, 2013).
One of the most intriguing research going on around asphalt pavement is exploring how nanoclays can be used in asphalt pavement (Gopalakrishnan, et al, 2011). A research on the effect of adding a little amount of nanoclay on asphalt pavement was conducted in Michigan Technological University (Lee, et al 2006). The results were a stronger asphalt pavement. That means the pavement is less prone to developing potholes, ruts and other common deformities (Gopalakrishnan, et al, 2011). The research group is further investigating how the asphalt pavement strengthened with nanoclay can stand against changing temperatures and other weather related challenges (Lee, et al 2006). Such improvements on asphalt pavement will make it even more favorable for users than it is already.
Some city governments have made efforts to maintain the asphalt pavements in their jurisdiction at their best. Some of the efforts include encouraging residents to report any observation of a damage on a pavement. Cities like Omaha and New York even have online channels of doing so (International Civil and Infrastructure Engineering Conference, et al, 2013). Such alerts from residents coupled with continuous assessment by the maintenance department ensures prompt repairs of damaged spots (White, 2002). Collaborative effort always delivers more.
In conclusion, saying that choosing asphalt pavements is a wise decision for a contractor is correct. Though it has a number of possible damages, a number of which can be extremely costly to repair, there are equally good measures to prevent them from happening. Technological advancements and research are further supporting asphalt pavements by coming up with new ways of making them stronger to prevent damage. With this assurance, users and owners can look forward to the continued use of this paving technique whose history can be traced to as way back in 625 B.C in the Babylonian reign.
The presence of a wide range of asphalt pavement experts that can be consulted is a comforting factor. It also supports increases the probability of success for the proposed solution, whose key to success is collaboration of various pavement experts. Institutions such as the Asphalt Institute and the National Asphalt Pavement Association have already made an effort to compile information, bring individual experts together as well as companies that deal with. With all that already done, the remaining part is for new pavement owners to harness these collaboration and have a durable asphalt surface installed at the best price possible.
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