Mix design considerations for asphalt wearing courses with high reclaimed asphalt content conference paper pdf available june 2015 with 2,141 reads how we measure reads. Ultra thin bonded wearing course the maryland asphalt. From the operational standpoint, the asphalt surface provides a wearing course to prevent material loss or dislodging e. Hot mix asphalt may be referred to by several names. Bonded wearing courses are constructed using polymermodified or rubber binders and gapgraded or opengraded aggregates. A proposal for asphalt wearing course specification in palestine. While a wearing course of surface dressing has been. Jan 23, 20 the department will designate the mixture for asphalt mixtures in accordance with the following.
Mastic asphalt is a mixture of bitumen, limestone, sand and coarse aggregate which are heated together in a sequential manner to form a homogeneous suspended composite material and laid on as desired. Asphalt wearing course compaction principle static pressure and dynamic energy key parameters static linear load vibrating mass amplitude frequency. Figures 3 and 4 illustrate two course and three course surface treatments respectively. Draft trh8 design and use of hot mix asphalt in pavements 1987. Ogfc, stone matrix asphalt sma, and ultrathin bonded wearing course utbwc. E geotextile type a on all subgrades chapter 8 rigid pavement design. Hma pavement mix type selection guide transportation.
The bonded wearing course consists of a warm polymer modified asphalt emulsion bond coat followed immediately with an ultrathin hot mix asphalt wearing course. In rigid pavements the upper layer is a portland cement concrete slab. The scope of work of this method statement is to describe the responsibilities of personnel involved, execution procedure, safety factors and documents to be recorded for asphalt paving works. Asphalt surface treatment, mat and seal square yard 24 section 661 25 ultrathin bonded wearing course 26 6611 description 27 produce and place an ultrathin bonded wearing course ubwc, including an application 28 of a warm polymermodified emulsion membrane pmem followed immediately with 29 an ubwc hot mix asphalt overlay. Mix design considerations for asphalt wearing courses with. Design scene chapter 10 paving page 2 revised 120817 tabulation sheet type sp 9. Bao1e1704 gravelsand vibratory compaction single drum rollers with circular exciter system application thin layers. While a wearing course of surface dressing has been known for its durability all over the world on.
The wearing course shall be evenly placed by mechanical spreader on a clean base in a manner that it does not become segregated. What is the density of asphalt wearing course answers. Densegraded mixtures utilized for thin lift overlays are often called no. The wearing course is the upper layer in roadway, airfield, and dockyard construction. Hot mix asphalt hma is a type of asphalt mixture commonly used as flexible pavement material. The other type uses a portland cement concrete wearing surface over a 7. Pdf durable wearing course for bituminous pavements. Design and construction guide for surface treatments over. Asphalt materials and paving mixtures asphalt materials. Asphalt concrete wearing course mixture specification free download as word doc. In most situations a dense asphalt concrete binder course will be the best choice. Pdf performance of asphalt concrete wearing course acwc. Asphalt rubber applications asphalt rubber is the process of adding recycled, crumb rubber to hot mix asphalt called dry process or the asphalt binder called wet process to modify the final mixture difficult to use in densegraded mixtures due to residual crumb rubber best used in gapgraded type mixtures sma and ogfc.
Pdf demands on natural aggregate materials for road pavement can be reduced by utilizing reclaimed asphalt pavement rap. Pdf a good wearing course is necessary for the protection of flexible pavement to make it durable. A one course surface treatment wearing surface is incapable of effectively servicing a roadway for an extended period. Introduction background the use of hotmix asphalt in south africa dates back to the 1920s when the larger cities felt the need for more durable surfacing materials to. Almost all state highway departments now allow the use of rap. A bonded wearing course bwc is a gap graded, ultra thin hotmix asphalt hma mixture applied over a thick polymer modified asphalt emulsion membrane. This pavement design guide,prepared by the pennsylvania asphalt pavement association papa, is provided for the practitioner architect, municipal and township engineer, and developer who to some extent is involved with the design of hotmix asphalt hma pavements of various types constructed in pennsylvania. Optimizing gradation design for ultrathin wearing course asphalt. Does tmr wish to permit the use of wma in heavy duty pavements. The need for an asphalt layer is mainly dictated by operational and structural considerations. Scope this work shall consist of constructing a single layer of mastic asphalt wearing course for road pavements and bridge decks. Module f lesson 5 hot mix asphalt mixtures and design concepts. Stone matrix asphalt open graded friction course dense mix. Erdcgsl tr1127 minimum thickness requirements for asphalt.
The supply and laying of open graded porous asphalt ogpa. Aggregate performancerelated properties for asphalt concrete. The asphalt institute strongly endorses the use of rap in asphalt mixtures. This idea is an enhancement of the compact asphalt pavement method, which is usually applied to build binder course and wearing course by a single paver. Highway agencies and asphalt industry groups have different. Asphalt wearing course asphalt base course static compaction single drum and tandem rollers applications surface compaction wet cohesive soils in thin layer applications applications. The supply and laying of textured high stress resistant type asphalts, such as. Pdf mix design considerations for asphalt wearing courses. Asphalt wearing course optimization for road traffic noise reduction. Conventional mixture design, construction of plantmixed plantmixed asphalt courses ms0310 fbmodified bituminous paving course ms0311 fb3 modified bituminous wearing course ms0321 bituminous wearing course fb2 ms0322 bituminous binder course fb2 ms0331 bituminous wearing course fb1 ms0332.
Wearing course page 4075 has the following statement. Performance based specification for hotmix asphalt wearing. To achieve a combination of both high strength and durability, eme2. Hma pavement mix type selection guide national asphalt pavement association 5100 forbes blvd. Method statement for asphalt paving works civil engineering.
It is similar to full depth asphalt except that a layer of granular material is placed on the subgrade first. In different sections of the state it may also be referred to as bituminous concrete,hot plant mix, asphalt concrete, blacktop or superpave. Fine gap graded asphalt wearing course foot traffic and residential streets 7, 10 open graded asphalt wearing course highways and freeways ultra thin asphalt urban and rural arterials 10, 14 10 intermediate, regulation and base course mixes dense graded asphalt intermediate course 10, 14, 20 dense graded asphalt regulating or levelling course. Therefore, multiple course surface treatments such as two course and three course surface treatments are typically used in wearing surfaces. The tack coat is spray applied immediately prior to the application of the wearing course to produce a durable wearing surface that can be opened to traffic. Method statement for asphalt paving works asphalt concrete. Chapter 11bonded wearing course november 21, 2007 11. The specifying agency or owner will set the limit for rap content. The structural concrete deck in a two course deck system uses epoxycoated or galvanized reinforcement. The binder course is a very important layer in the road structure as it experiences high stress and is at risk of exposure to water. The term surface course is sometimes used, however this term is slightly different as it can be used to describe very thin surface layers such as chip seal.
The construction managerproject engineer is responsible for the asphalt paving works. Scope this specification sets out the performance requirements for the following types of asphalt as wearing courses. Asphalt wearing course optimization for road traffic noise. Method statement for asphalt paving works are given below. The tack coat is spray applied immediately prior to the application of the wearing course to produce a durable wearing surface that. However, hma has weaknesses in terms of high mixing and compaction temperature, resulting in high co2 and greenhouse gas ghg emissions which have a. The high binder content seals the underlying road thereby protecting it from water infiltration and slows down the aging process. Hot mix asphalt is composed of aggregate bound together into a solid mass by asphalt cement. Wearing course shall be placed in one layer above the bituninous base course and one coat of tack coat shall be applied between bituminous base course and wearing course. Hotmix asphalt, mix design, design criteria, surfacing, base layer, levelling course, aggregate. The performance of warm mix for the asphalt concrete wearing. Asphalt concrete wearing course mixture specification scribd. Introduction background the use of hotmix asphalt in south africa dates back to the 1920s when the larger cities felt the need for more durable surfacing materials to pave their increasingly heavily trafficked streets. Design of longlife flexible pavements for heavy traffic.