Asphalt mix design 2 australian asphalt pavement association 2012 2 design process asphalt mix design involves the following basic steps that are similar in concept, regardless of the actual tests and procedures used. About course author paul guyer is a registered mechanical engineer, civil engineer, fire protection engineer and architect with over 35 years experience in the design of buildings and related infrastructure. Note 9when using warm mix asphalt wma additives in the mixture design, verify. The marshall mixture design method shall not be used unless approved by the engineer. Properties considered in mix design superpave mix design method. Pavement materials and construction techniques laboratory records submission date. Properties considered in mix design superpave mix design. The site is a repository for encyclopedic articles, news, and information on all topics related to pavements. Optimized mix design approach national asphalt pavement. Overview the sample is heated in a furnace at 538c f or less. Pdf stripping is the separation of the asphalt binder film from the aggregate surface due to the. This procedure covers the determination of asphalt binder content of hot mix asphalt hma by ignition of the binder in accordance with aashto t 30810.
The mix design serves as an initial job mix formula, the same as in hot mix asphalt hma construction. Add mix sample to beaker, maintain boil for 10 m 30 s. The mix components as listed on this design were used to perform our work. Practical approaches to hotmix asphalt mix design and. Mixtures with high vma are preferred because of the following advantages. Calculate the bearing capacity for each asphalt content. A manual for design of hotmix asphalt with commentary incorporates the many advances in materials characterization and hotmix asphalt hma mix design technology developed since the conclusion of the strategic highway research program shrp. Mix design project vb 0114104 the mix design was optimized using four asphalt contents 4. Ensure that you collect enough material for section 5. Procedures for sampling asphalt mixturesdensity cores and. Figure 3 sample preparation and capture of highresolution images by sem.
High vma values allow enough asphalt to be incorporated into the mix to obtain maximum durability without the mix flushing. Equations for the above calculations follow in this text and their application may be expedited by use of the appropriate worksheet figure 1. All in all, about two million tons of hotmix asphalt are used annually in south africa. Density is important because proper density in the finished product is essential for lasting pavement performance.
There is also research underway to adopt superpave technology to cr mixtures. This method also addresses the treatment of reclaimed asphalt pavement rap for mix design purposes section 7. Pavement interactive is a free online knowledge base for the paving industry. Key words asphalt, segregation, binder, sampling location, sample reduction, asphalt content 18. A local asphalt mix producers 19 mm, e1 mix design was used to incorporate the glass aggregates into and to provide a standard asphalt mix to which mix properties could be compared. Pavements task force 38 contains mix design procedures for both marshall and hveem equipment and many states use it or modified marshall or hveem. The first article covering the early design practices through the marshall and hveem systems was published in the spring 20 issue of asphalt magazine. Draft trh8 design and use of hot mix asphalt in pavements 1987. The mix design for hot mix asphalt pavement hma shall conform to the criteria of design and production tables below. Method b this method samples the asphalt mixture from behind the paver using a shovel after placement of the asphalt mat and prior to compaction. This is an introduction to the methods and materials employed in hot mix asphalt pavement design and construction. These hot mix asphalt mixtures are particularly suitable for airfield pavements, roads and streets, and storage areas. History of asphalt mix design in north america, part 1.
National center for asphalt technology ncat 1996 hotmix asphalt materials, mixture design and construction, napa, lanham, md, 585 pp. Note 9when using warm mix asphalt wma additives in. Group 1 20cez8070 priyansh singh 20cep2073 aayush kumar 20cep2074 anjaneyulu chinthireddy 20cep2080 leeza malik 20cep2083 munesh kumar meena 20cep2778 yohannes legessedadi 20cep2086 saubhagya dixit. The report presents special mixture design considerations and methods used with warm mix asphalt. The engineer and contractor will select sampling locations using a random selection method. Although astm was the main home of the marshall method d1889, the method was a reflection of ms2.
The asphalt institute 1997 mix design methods for asphalt concrete and other hotmix types ms2, 6th ed. The final mix design should be workable and contain the most suitable gradation and amount of asphalt binder to produce a mix that embodies the best possible combination of all parameters. It serves as a resource for contractors, government agencies, consultants, and others in the transportation infrastructure industry. Pdf evaluation the effect of asphalt film thickness on stripping.
All in all, about two million tons of hot mix asphalt are used annually in south africa. Chapter 2 design and control of bituminous mixtures using a. Other characteristics durable ages well with time rheology or deformation with temperature too warmtoo much flow can cause rutting too coldtoo little flow can cause cracking purity pure bitumen most current asphalt pavement design approach is based. Prepare g of mix, cool at room temp for 24 2 hrs bring oil bath to between 325 and 350of obtain a 200 g representative sample of the mix fill 2000 ml beaker about halfway with distilled water and heat to boiling add mix sample to beaker, maintain boil for 10 m 30 s remove beaker and skim asphalt from water surface. Asphalt mix design free download as powerpoint presentation.
The table below lists the mix properties at the optimum asphalt content chosen 5. Required quality lowest cost for required quality manageable risk level an optimized design approach should yield a mix which meets the mix design and production goals. Evaluation of vma and film thickness requirements in hot. A manual for design of hotmix asphalt with commentary the. Marshall mix design select and test aggregate select and test asphalt cement establish mixing and compaction temperatures develop trial blends heat and mix asphalt cement and aggregates compact specimen 102 mm diameter bit. An introduction to hot mix asphalt for pavement a pdh. The purpose of this guidance note is to ensure that a standardized method is applied to the design procedure.
This document is not a report of the national research council or. Hot mix asphalt mixtures consist of mineral aggregate and asphalt cement. This study indicates that there is no statistically significant difference in asphalt content of the allowed cdot sampling locations. Develop an economical blend of aggregates and asphalt that meet design requirements historical mix design methods marshall hveem new superpave gyratory for more info log on to patcivil. Obtaining the correct air void content is critical in both mix design and the inservice performance of a pavement. Practical approaches to hotmix asphalt mix design and production. Mix design for hma recycling national asphalt pavement. These hotmix asphalt mixtures are particularly suitable for airfield pavements, roads and streets, and storage areas. National center for asphalt technology ncat 1996 hot mix asphalt materials, mixture design and construction, napa, lanham, md, 585 pp. A manual for design of hotmix asphalt with commentary.
The optimum percent asphalt cement content shall be chosen in accordance with asphalt institute manual ms2. T c is a derived asphalt binder property that has been gaining attention for the last decade. Conduct tests on mixtures of aggregate and asphalt using marshall apparatus as described in kansas test method kt14, and plot the resulting data on kdot form no. Pg 6422 asphalt conoco phillips, wood river, il december 6, 2012 discussion.
In january 2012, trb released an errata to nchrp report 673. Calculate the limiting asphalt content at the tentative design asphalt content. Asphalt mix design guide aapa australian asphalt pavement. Page 41, table 47, and page 123, table 810, respectively, should be replaced with a new table. Evaluation of vma and film thickness requirements in hotmix. The purpose of this document is to provide a guide to the asphalt mix design process. Pdf validity of asphalt binder film thickness concept in hotmix. The sampling locations are to be marked prior to rolling and the samples taken after the paving train. History of asphalt mix design in north america, part 2. Pdf despite the possible benefits of implementing asphalt binder film thickness into current specifications to address durability problems, most of.
Including the vfa requirement in a mix design helps prevent the design of hma with marginally acceptable vma. The 7 th edition of ms2 asphalt mix design methods marks the 56 th year of continuous publication of an asphalt institute mix design manual. Superpave mix design was developed as part of the strategic highway research program shrp from 1987 to 1993. This webinar provides the student with a detailed overview of the process for conducting an asphalt mix design using rap. Group 1 20cez8070 priyansh singh 20cep2073 aayush kumar 20cep2074 anjaneyulu chinthireddy 20cep2080 leeza malik. Asphalt concrete mix design video presentation youtube. 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. Asphalt rubber methods of adding rubber to asphalt wet process rubber is added to the liquid asphalt binder before being mixed at the hot mix asphalt plant i. This study suggests that no changes are needed to cp41 for sampling all hot mix asphalt. Since a thick binder film on the aggregate particles results in. The contractor is required to design the asphalt mix and to obtain an approved job mix formula jmf issued by the department. Voids filled with asphalt vfa are the void spaces that exist between the aggregate particles in the compacted paving hma that are filled with binder.
Method a this method samples the asphalt mixture from behind the paver using a plate placed on the roadway prior to placement of the asphalt mat. Marshall method of mix design the basic concepts of the marshall mix design method were originally developed by bruce marshall of the mississippi highway department around 1939 and then refined by the u. At present, hot mix asphalt is used extensively for bases and surfacings for new construction, as well as for overlays in the maintenance and rehabilitation of existing pavements. Component diagram of compacted sample of hot mix asphalt bulk specific gravity or density the density of the compacted mix is the unit weight of the mixture the weight of a specific volume of hma. Asphalt institute ms2 7th edition 2014 asphalt mix design methods ingilizce orijinal. May 17, 2017 asphalt concrete mix design basics dragos andrei.
The asphalt institute 1997 mix design methods for asphalt concrete and other hot mix types ms2, 6th ed. Mix design considerations include virgin asphalt binder grade selection, testing of rap materials, laboratory handling, and analysis procedures needed to conduct a successful asphalt mix design using rap. For example, variation in the specific gravity or absorption of an aggregate source from. The ac properties do agree with the specifications of the ministry of. Vfa is expressed as a percentage of the vma that contains binder. This is the second of two articles on the history of mix design. Asphalt qms manual 04 asphalt mix design and job mix. At present, hotmix asphalt is used extensively for bases and surfacings for new construction, as well as for overlays in the maintenance and rehabilitation of existing pavements. Effective asphalt content pbe is defined as the total asphalt content of a paving mixture minus the portion of asphalt absorbed into the aggregate particles see fig.
Pdf development of a new asphalt mix design manual for. The manual is a practical guide based on proven technologies, incorporating the most current information available at the time of writing. Asphalt mix design manual for south africa, provisional working document november 2014. Verification of design properties on samples of manufactured asphalt. Additionally, such mixes have the following advantages compared to low vma mixes. A copyof the mix design report is included in appendix b. Optimized mix design mix design and production goals mix design goals stability. Monitor and coordinate the progress of other team members involved in the design process. Bibliography the asphalt institute 2001 superpave mix design sp2, 128 pp. Read a manual for design of hotmix asphalt with commentary. The marshall stability of the mix design is defined as a maximum load carried by a compacted specimen at a standard temperature of 60 oc. It has become a topic of focus to both researchers in the asphalt binder technical community and user agencies seeking physical property parameters that will improve hot mix asphalt pavement performance. This test method is for use with mixtures containing penetration and viscosity or performance grade asphalt cements and aggregate up to 25 mm maximum size.
Complete the documentation of the asphalt mix design. In general, from 3 to 6 percent asphalt is required for asphalt base or intermediate courses, 4 to 7. Hotmix asphalt mixtures consist of mineral aggregate and asphalt cement. When a sample of asphalt mixture is prepared in the laboratory, the asphalt mixture is analyzed to. Special mixture design considerations and methods for wma nchrp 943 products nchrp report 691 recommended draft appendix to aashto r35, special mixture design considerations and methods for warm mix asphalt wma commentary to the draft appendix training materials for the draft appendix nhi webcourse september 2011. Trbs national cooperative highway research program nchrp report 673.