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  • Rehabilitation | Washington Asphalt Pavement Association
    existing pavement wearing course Because of this they contribute very little to the pavement structure and are generally assumed to provide no additional structural support Because most agencies consider non structural overlays to be maintenance items they are discussed on the Maintenance page Hot in place recycling HIR Covered in the Pavement Types section Cold in place recycling CIR Covered in the Pavement Types section Full depth reclamation FDR is considered reconstruction Figures 1 Pavement Rehabilitation Figures 2 Pavement Rehabilitation WAPA Pavement Note on Rehabilitation A wholesale replacement of the entire pavement structure is considered reconstruction rather than rehabilitation since it follows new pavement construction methods Structural Overlays Structural overlays are used to increase pavement structural capacity Therefore they are considered rehabilitation although they typically have some maintenance type benefits as well Asphalt concrete structural overlay design can be broadly categorized into the following modified after Monismith and Finn 1984 Engineering judgment This approach to overlay design selects an overlay thickness and the associated materials based on local knowledge of existing conditions which can result in cost effective solutions however local expertise is fragile and subject to retirements agency reorganizations etc This method is highly subjective and can be heavily influenced by political and budget constraints Currently more agencies appear to be relying on quantifiable overlay design approaches but tempered with local expertise Component analysis This approach to overlay design essentially requires that the total pavement structure be developed as a new design for the specified service conditions and then compared to the existing pavement structure taking into account pavement condition type and thickness of the pavement layers Current component design procedures require substantial judgment to effectively use them This judgment is mainly associated with selection of weighting factors to use in evaluating the structural adequacy of the existing pavement

    Original URL path: http://www.asphaltwa.com/2010/09/17/rehabilitation/ (2016-04-26)
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  • Residential Streets | Washington Asphalt Pavement Association
    loadings Truck traffic is limited to those vehicles that provide residential services such as garbage trucks delivery trucks and the occasional moving van Vehicle Type Vehicles per day Vehicles per year ESALs per year Cars and Light Trucks 500 200 000 140 Medium Trucks and Buses 10 4 000 80 Heavy Trucks and Buses negligible negligible negligible Totals 510 204 000 220 Design Considerations If buses school or public transit use or are anticipated to use the residential street on a regular basis the street should be designed using an approved design procedure Construction Considerations If the residential street is fully paved before the surrounding homes are built the pavement may be damaged by heavy construction traffic such as loaded dump trucks material delivery vehicles and construction equipment In most cases it is advantageous to pave a residential street in two stages First before home construction beings a layer of ATB in accordance with site paving thicknesses creates a paved street that allows construction vehicles to access the site without tracking mud or damaging the subgrade It also allows potential buyers the opportunity to see their homes in a cleaner environment Recommended References American Association of State Highway and Transportation

    Original URL path: http://www.asphaltwa.com/2010/09/17/residential-streets-2/ (2016-04-26)
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  • Collector Streets | Washington Asphalt Pavement Association
    Events Home Collector Streets Collector Streets Collector Streets Collector streets connect the residential streets with arterial routes They may have significant truck and bus traffic and their closure for paving could create substantial commuter delays Figures 1 Collector Streets Figures 2 Collector Streets Assumed Traffic Low to intermediate speed moderate traffic volume and some heavy loadings Truck traffic can often include substantial amounts of delivery vehicles school buses and sometimes public transit buses Vehicle Type Vehicles per day Vehicles per year ESALs per year Cars and Light Trucks 3 500 1 300 000 900 Medium Trucks and Buses 100 36 500 9 000 Heavy Trucks and Buses 20 7 000 10 000 Totals 3 620 1 343 500 19 900 Design Considerations Collector street traffic loading can vary widely High traffic streets specifically those with substantially higher heavy truck and bus traffic levels than those listed above should be designed using an approved structural design procedure Construction Considerations Consideration should be given to paving in two separate lifts to allow street use with only minimal delays during construction Any localized failures in the first lift can be repaired before final lift placement Recommended References American Association of State Highway and

    Original URL path: http://www.asphaltwa.com/2010/09/17/collector-streets-2/ (2016-04-26)
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  • Rural Roads | Washington Asphalt Pavement Association
    traffic Speeds vary but in many locations they can approach highway speeds Figure 1 Rural Road in Grandview Assumed Traffic Low to high speed low traffic volume and some heavy loadings Heavy truck traffic is usually limited to those involved with local services and delivery or farm machinery Vehicle Type Vehicles per day Vehicles per year ESALs per year Cars and Light Trucks 1 500 500 000 300 Medium Trucks and Buses 20 7 000 1 800 Heavy Trucks and Buses occasional 50 50 Totals 1 520 507 050 2 150 Design Considerations Rural road loading can vary widely Roads that are part of bus routes or are commonly used by heavy trucks such as roads next to a gravel quarry should be designed using an approved procedure Construction Considerations Rural roads are often been built on minimally prepared subgrade which can lead to subgrade failure resulting in fatigue cracking and depressions see Figures 1 and 2 Special attention should be paid to questionable subgrade areas and nearby fill embankments than may erode causing an edge depression or failure A construction geotextile can be used to help stabilize roadways with early signs of subgrade failure or extensive cracking However extensive

    Original URL path: http://www.asphaltwa.com/2010/09/17/rural-roads-2/ (2016-04-26)
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  • Arterials & Highways | Washington Asphalt Pavement Association
    Paving Awards Winners How To Apply Calendar Industry Events WAPA Events Home Arterials Highways Arterials Highways Arterials Highways Arterials roads provide service to large areas and usually connect with other arterial roads or highways They are generally characterized by high traffic volume heavy loading and widely varying speeds Highways are roads that provide primary transportation routes between geographic locations such as cities and towns They are characterized by varying traffic volume heavy loading and widely varying speeds Figure 1 Aurora Avenue Figure 2 US 97 South of Blewett Pass Assumed Traffic Due to its extremely varied nature it is not possible to provide a simple generalization of arterial and highway traffic Some highways such as I 5 in Tacoma may experience as many as 100 million ESALs during their design life while others may experience less than 1 million ESALs Design Considerations Arterials and highways require special design considerations These pavements should only be designed using an approved structural design procedure well reasoned mix type selection and proper mix design Construction Considerations Each arterial and highway construction project requires project specific considerations Recommended References American Association of State Highway and Transportation Officials AASHTO 1993 AASHTO Guide for Design of Pavement

    Original URL path: http://www.asphaltwa.com/2010/09/17/arterials-highways/ (2016-04-26)
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  • Design Catalog | Washington Asphalt Pavement Association
    Heavy Industrial Facilities Airfields Site Paving Awards Winners How To Apply Calendar Industry Events WAPA Events Home Design Catalog Parking Lots Parking lots are paved areas intended for vehicle parking and can vary widely in size function and design This page gives some general guidance when designing at grade parking lot pavements Read More Residential Driveways Residential driveways are small pavement sections intended for automobile use and parking with only an occasional medium truck Read More Pathways Bicycle walking and golf cart paths are specifically intended for bicycles golf carts pedestrians and other non vehicular traffic They are generally thinner than vehicular pavement and usually have a very smooth surface Read More Recreational Facilities Recreational facilities include playgrounds tennis courts basketball courts and just about any other surface intended primarily for pedestrian use Read More Heavy Industrial Facilities Heavy industrial facilities encompasses any facility for use with heavily loaded vehicles such as industrial drives truck parking bus terminals warehouse loading areas log storage areas and container lots HMA is a durable high strength pavement material that is entirely appropriate for industrial facilities Read More Airfields Airfield pavements are intended primarily for airplane traffic in stationary taxiing and takeoff landing modes

    Original URL path: http://www.asphaltwa.com/category/7/page/2/ (2016-04-26)
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  • Parking Lots | Washington Asphalt Pavement Association
    pedestrian friendly and easily maintainable for a minimal cost Specific considerations are Heavy truck traffic Most parking lots will experience at least some heavy truck traffic related to goods delivery and pick up If possible heavy truck travel should be restricted to designated areas and then only these areas should be designed to accommodate heavy truck loading Thus pavements are made thicker where heavy trucks are likely to travel e g to and from the loading dock and are made thinner where only passenger cars and light trucks are expected e g in the individual parking stalls Design parking lot geometry to minimize handwork and maximize long straight paver pulls Handwork the placement of HMA by hand shoveling and raking is more expensive and results in a rougher surface texture than pavement placed by a paver Although these areas should last just as long as the rest of the parking lot they often do not look as good and their roughness may be unpleasant to walk on or roll a shopping cart across In short the less handwork the better Additionally the highest quality pavement is generally placed by a continuously moving paver that does not have to repeatedly stop and start Specific guidance follows Design parking plans should allow for long uninterrupted straight paver pulls Unusual non square geometry and odd shaped islands make for short paver pulls and create portions of the parking lot inaccessible to the paver that have to be paved by hand Minimize the use of planter islands in the middle of the parking lot Lots of planter islands result in shorter paver pulls and more paver inaccessible areas requiring handwork As an alternative consider placing planters around the parking lot perimeter or paving the parking lot then sawcutting out areas to be built into planters Drains should follow straight lines so the paver can parallel these lines during laydown Since only a fixed contour can be laid in one pass of an asphalt paver designs calling for a meandering gutter or valley require hand placing Drain lines that parallel the long dimension of the parking lot allow for longer paver pulls Drainage Well drained parking lots last significantly longer than poorly drained parking lots To ensure adequate drainage Design parking lots with a minimum slope of 2 percent 0 25 inches per foot Slopes less than this are difficult to construct and may not prevent pooling of water during wet weather It is extremely difficult to prevent pooling in parking lots sloped less than 1 5 percent especially when the lot is newly paved Where parking lot geometry necessitates hand placed pavement an increase in minimum slope to 4 percent 0 5 inches per foot should be considered Fine grade control is more difficult with hand placement than with machine placement Parking lots placed in cut areas are more susceptible to moisture problems When placing a parking lot in a large cut area cannot be avoided take extra care in developing a good drainage

    Original URL path: http://www.asphaltwa.com/2010/09/17/parking-lots-2/ (2016-04-26)
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  • Residential Driveways | Washington Asphalt Pavement Association
    Rice density Lower levels of compaction may result in driveways that will significantly compact under a parked car load or scuff as a result of turning an automobile s wheels while it remains parked Driveways should be constructed with HMA and not cold mix asphalt Cold mix asphalt is typically used for emergency repairs and will often not stand up to even light automobile loads on hot days Turning an automobile s wheels while it remains parked can considerably scuff cold mix asphalt Where there is the possibility of recurrent vegetation growth a quality commercial grade herbicide should be used WAPA Pavement Note on Driveway Paving Scams Unfortunately salesmen going door to door offering to pave driveways at very low cost is a common home construction scam The typical scenario but by no means the only scenario begins with a salesman at a customer s door offering to pave their driveway for a very low cost because they have some left over mix from another close by job If the customer agrees to the work the scam artist will often request payment up front or in cash They then either do a poor job using inferior equipment and materials do an incomplete job and leave or just leave without doing any work These scams typically result in unsatisfied consumers who end up paying for inferior work that often must be replaced A driveway paving project should be treated like any other major home improvement project The Attorney General of Washington Consumer Protection Division has some basic guidelines for contractor selection Some of the driveway paving scam warning signs are Selling door to door Reputable HMA contractors will rarely if ever sell their product door to door Claiming they have left over mix Often a scam artist will claim they have

    Original URL path: http://www.asphaltwa.com/2010/09/17/residential-driveways-2/ (2016-04-26)
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