Transcription

STANDARD SPECIFICATIONSforTRANSPORTATION MATERIALSandMETHODS OF SAMPLING AND TESTINGandPROVISIONAL STANDARDS40TH EDITIONGROUP 1 (APRIL 2020)GROUP 2 (JUNE 2020)GROUP 3 (JULY 2020)PART 1: SPECIFICATIONS AND PRACTICESPART 2: TEST METHODSPART 3: PROVISIONALSAdopted by the

ABOUT AASHTO DESIGNATION NUMBERSAnatomy of a Designation NumberComponentsT xxx - 16Standard TypeTwo-Digit Revision YearStandard NumberM xxx-12 (2016)Four-Digit Reconfirmation YearStandard TypesStandard types are represented by a one-letter abbreviation for full standards. The letter “P” is added for provisionalstandards. The standard type abbreviations are as follows: M (Materials, full)T (Test, full)R (PRactice, full) MP (Materials, provisional)TP (Test, provisional)PP (Practice, provisional)Standard NumbersStandard numbers are sequential within standard type. Thus, a provisional that is subsequently adopted as a fullstandard will receive a new number.Revised vs. Reconfirmed and Discontinued vs. DeletedA full or provisional standard is designated as revised if technical changes have been balloted and approved byAASHTO’s Highways Subcommittee on Materials. A standard is designated as reconfirmed if it has undergonetechnical review to determine that it is up to date and in use and that it does not require revision; such a review isrequired: every four years for a full standard, andevery one or two years for a provisional standard, depending on its progress through its 8-year provisionallife cycle.If a standard is no longer used, it may be discontinued by Subcommittee vote, in which case the standard headerwill be published that year with a notice saying that the standard has been discontinued and giving a briefexplanation as to why. In subsequent years, the standard will be deleted from the book, meaning that it is no longermaintained.

PART 1—STANDARD SPECIFICATIONS AND STANDARD PRACTICESSubject Sequence Table of ContentsMaster List (All Release Groups)STD. NO.TITLEGROUP(MONTH)AGGREGATESM 6-13 (2018)Fine Aggregate for Hydraulic Cement Concrete3 (July)M 17-11 (2019)Mineral Filler for Bituminous Paving Mixtures3 (July)M 29-12 (2020)Fine Aggregate for Bituminous Paving Mixtures3 (July)M 43-05 (2013)Sizes of Aggregate for Road and Bridge Construction3 (July)M 45-16 (2020)Aggregate for Masonry Mortar3 (July)M 80-13 (2017)Coarse Aggregate for Hydraulic Cement Concrete3 (July)M 195-11 (2019)Lightweight Aggregates for Structural Concrete3 (July)M 327-19Processing Additions for Use in the Manufacture of Hydraulic Cements1 AprilR 76-16 (2020)Reducing Samples of Aggregate to Testing Size3 (July)R 90-18Sampling Aggregate Products3 (July)R 91-18Determining Aggregate Source Shape Values from Digital Image Analysis Shape Properties3 (July)TITLEGROUP(MONTH)STD. NO.BITUMINOUS MATERIALSM 81-92 (2017)Cutback Asphalt (Rapid-Curing Type)3 (July)M 82-17Cutback Asphalt (Medium-Curing Type)3 (July)M 140-20Emulsified Asphalt3 (July)M 156-13 (2017)Requirements for Mixing Plants for Hot-Mixed, Hot-Laid Bituminous Paving Mixtures3 (July)M 208-18Cationic Emulsified Asphalt3 (July)M 226-80 (2017)Viscosity-Graded Asphalt Cement3 (July)M 316-18Polymer-Modified Emulsified Asphalt3 (July)M 320-17Performance-Graded Asphalt Binder3 (July)M 323-13Superpave Volumetric Mix Design3 (July)M 325-08 (2017)Stone Matrix Asphalt (SMA)3 (July)M 327-19Processing Additions for Use in the Manufacture of Hydraulic Cements1 AprilM 332-20Performance-Graded Asphalt Binder Using Multiple Stress Creep Recovery (MSCR) Test3 (July)R 5-17Selection and Use of Emulsified Asphalts3 (July)R 15-18Asphalt Additives and Modifiers3 (July)R 26-01 (2018)Certifying Suppliers of Performance-Graded Asphalt Binders3 (July)R 28-12 (2016)Accelerated Aging of Asphalt Binder Using a Pressurized Aging Vessel (PAV)3 (July)R 29-15 (2019)Grading or Verifying the Performance Grade (PG) of an Asphalt Binder3 (July)R 30-02 (2019)Mixture Conditioning of Hot Mix Asphalt (HMA)3 (July)R 35-17Superpave Volumetric Design for Asphalt Mixtures3 (July)R 46-08 (2017)Designing Stone Matrix Asphalt (SMA)3 (July)R 47-19Reducing Samples of Asphalt Mixtures to Testing Size3 (July)

STD. NO.TITLEGROUP(MONTH)BITUMINOUS MATERIALSR 49-09 (2018)Determination of Low-Temperature Performance Grade (PG) of Asphalt Binders3 (July)R 59-11 (2019)Recovery of Asphalt Binder from Solution by Abson Method3 (July)R 62-13 (2017)Developing Dynamic Modulus Master Curves for Asphalt Mixtures3 (July)R 66-16 (2020)Sampling Asphalt Materials3 (July)R 67-20Sampling Asphalt Mixtures after Compaction (Obtaining Cores)3 (July)R 68-15 (2019)Preparation of Asphalt Mixtures by Means of the Marshall Apparatus3 (July)R 77-16 (2020)Certifying Suppliers of Emulsified Asphalt3 (July)R 78-16 (2020)Recovering Residue from Emulsified Asphalt Using Low-Temperature EvaporativeTechniques3 (July)R 79-19Vacuum Drying Compacted Asphalt Specimens3 (July)R 83-17Preparation of Cylindrical Performance Test Specimens Using the Superpave GyratoryCompactor (SGC)3 (July)R 84-17Developing Dynamic Modulus Master Curves for Asphalt Mixtures Using the AsphaltMixture Performance Tester (AMPT)3 (July)R 92-18Evaluating the Elastic Behavior of Asphalt Binders Using the Multiple Stress CreepRecovery (MSCR) Test3 (July)STD. NO.TITLEGROUP(MONTH)BOX CULVERT, CULVERT PIPE, AND DRAIN TILEM 36-16 (2020)Corrugated Steel Pipe, Metallic-Coated, for Sewers and Drains2 (June)M 86M/M 86-20Nonreinforced Concrete Sewer, Storm Drain, and Culvert Pipe2 (June)M 167M/M 167-17Corrugated Steel Structural Plate, Zinc-Coated, for Field-Bolted Pipe, Pipe-Arches, andArches2 (June)M 170-20Reinforced Concrete Culvert, Storm Drain, and Sewer Pipe2 (June)M 170M-20Reinforced Concrete Culvert, Storm Drain, and Sewer Pipe [Metric]2 (June)M 175M/M 175-05 (2020)Perforated Concrete Pipe2 (June)M 176M/M 176-20Porous Concrete Pipe2 (June)M 178M/M 178-20Concrete Drain Tile2 (June)M 190-04 (2017)Asphalt-Coated Corrugated Metal Culvert Pipe and Pipe-Arches2 (June)M 196-16Corrugated Aluminum Pipe for Sewers and Drains2 (June)M 197-20Aluminum Alloy Sheet for Corrugated Aluminum Pipe2 (June)M 199M/M 199-17Precast Reinforced Concrete Manhole Sections2 (June)M 206M/M 206-20Reinforced Concrete Arch Culvert, Storm Drain, and Sewer Pipe2 (June)M 207M/M 207-20Reinforced Concrete Elliptical Culvert, Storm Drain, and Sewer Pipe2 (June)M 218-03 (2020)Steel Sheet, Zinc-Coated (Galvanized), for Corrugated Steel Pipe2 (June)M 219-92 (2017)Corrugated Aluminum Alloy Structural Plate for Field-Bolted Pipe, Pipe-Arches, andArches2 (June)M 242M/M 242-20Reinforced Concrete D-Load Culvert, Storm Drain, and Sewer Pipe2 (June)M 243-96 (2017)Field-Applied Coating of Corrugated Metal Structural Plate for Pipe, Pipe-Arches, andArches2 (June)M 245-20Corrugated Steel Pipe, Polymer-Precoated, for Sewers and Drains2 (June)

STD. NO.TITLEGROUP(MONTH)BOX CULVERT, CULVERT PIPE, AND DRAIN TILEM 246-15 (2019)Steel Sheet, Metallic-Coated and Polymer-Precoated, for Corrugated Steel Pipe2 (June)M 252-20Corrugated Polyethylene Drainage Pipe2 (June)M 259-20Precast Reinforced Concrete Box Sections for Culverts, Storm Drains, and Sewers2 (June)M 259M-17Discontinued—Precast Reinforced Concrete Box Sections for Culverts, Storm Drains, andSewers [Metric]2 (June)M 262-11 (2020)Concrete Pipe and Related Products2 (June)M 273-20Precast Reinforced Concrete Box Sections for Culverts, Storm Drains, and Sewers with LessThan 2 ft of Cover Subjected to Highway Loadings2 (June)M 273M-17Discontinued—Precast Reinforced Concrete Box Sections for Culverts, Storm Drains, andSewers with Less Than 0.6 m of Cover Subjected to Highway Loadings [Metric]2 (June)M 274-87 (2017)Steel Sheet, Aluminum-Coated (Type 2), for Corrugated Steel Pipe2 (June)M 278-15Class PS46 Poly(Vinyl Chloride) (PVC) Pipe2 (June)M 289-91 (2017)Aluminum-Zinc Alloy Coated Sheet Steel for Corrugated Steel Pipe2 (June)M 294-18Corrugated Polyethylene Pipe, 300- to 1500-mm (12- to 60-in.) Diameter2 (June)M 304-11 (2015)Poly(Vinyl Chloride) (PVC) Profile Wall Drain Pipe and Fittings Based on ControlledInside Diameter2 (June)M 306-10 (2019)Drainage, Sewer, Utility, and Related Castings2 (June)M 326-18Polyethylene (PE) Liner Pipe, 300- to 1600-mm Diameter, Based on Controlled OutsideDiameter2 (June)M 330-20Polypropylene Pipe, 300- to 1500-mm (12- to 60-in.) Diameter2 (June)M 335-19Steel-Reinforced Polyethylene (PE) Ribbed Pipe, 300- to 1500-mm (12- to 60-in.) Diameter2 (June)R 63-13 (2017)Solid Wall High-Density Polyethelene (HDPE) Conduit for Non-Pressure ApplicationsUsed for the Protection of Power and Telecommunications Cables2 (June)R 73-16 (2020)Evaluation of Precast Concrete Drainage Products2 (June)R 82-17Pipe Joint Selection for Highway Culvert and Storm Drains2 (June)R 93-19Service Life Determination of Corrugated HDPE Pipes Manufactured with RecycledContent2 (June)STD. NO.TITLEGROUP(MONTH)CONCRETE, CURING MATERIALS, AND ADMIXTURESM 154M/M 154-12 (2020)Air-Entraining Admixtures for Concrete1 (April)M 157-13 (2017)Ready-Mixed Concrete1 (April)M 182-05 (2017)Burlap Cloth Made from Jute or Kenaf and Cotton Mats1 (April)M 194M/M 194-13 (2017)Chemical Admixtures for Concrete1 (April)M 205M/M 205-11 (2019)Molds for Forming Concrete Test Cylinders Vertically1 (April)M 233-86 (2014)Boiled Linseed Oil Mixture for Treatment of Portland Cement Concrete2 (June)M 241M/M 241-13 (2017)Concrete Made by Volumetric Batching and Continuous Mixing1 (April)M 295-19Coal Fly Ash and Raw or Calcined Natural Pozzolan for Use in Concrete1 (April)M 302-19Slag Cement for Use in Concrete and Mortars1 (April)R 39-19Making and Curing Concrete Test Specimens in the Laboratory1 (April)R 60-12 (2020)Sampling Freshly Mixed Concrete1 (April)

STD. NO.TITLEGROUP(MONTH)CONCRETE, CURING MATERIALS, AND ADMIXTURESR 64-17Sampling and Fabrication of 50-mm (2-in.) Cube Specimens Using Grout (Non-Shrink) orMortar1 (April)R 70M/R 70-18Use of Apparatus for the Determination of Length Change of Hardened Cement Paste,Mortar, and Concrete1 (April)R 72-16 (2020)Match Curing of Concrete Test Specimens1 (April)R 80-17Determining the Reactivity of Concrete Aggregates and Selecting Appropriate Measures forPreventing Deleterious Expansion in New Concrete Construction1 (April)R 81-17Static Segregation of Hardened Self-Consolidating Concrete (SCC) Cylinders1 (April)STD. NO.TITLEGROUP(MONTH)ENVIRONMENTAL TESTSR 23-99 (2018)Chemical, Biological, and Physical Analysis of Water1 (April)R 24-99 (2018)Collection and Preservation of Water Samples1 (April)STD. NO.TITLEGROUP(MONTH)GUARDRAIL AND FENCINGM 180-12 (2017)Corrugated Sheet Steel Beams for Highway Guardrail2 (June)M 181-10 (2019)Chain-Link Fence2 (June)M 269-96 (2018)Turnbuckles and Shackles2 (June)M 279-14 (2018)Metallic-Coated, Steel Woven Wire Fence Fabric2 (June)M 280-20Metallic-Coated (Carbon) Steel Barbed Wire2 (June)M 281-96 (2018)Steel Fence Posts and Assemblies, Hot-Wrought2 (June)STD. NO.TITLEGROUP(MONTH)HYDRAULIC CEMENTM 85-20Portland Cement1 (April)M 240M/M 240-20Blended Hydraulic Cement1 (April)M 307-13 (2017)Silica Fume Used in Cementitious Mixtures1 (April)M 321-04 (2017)High-Reactivity Pozzolans for Use in Hydraulic-Cement Concrete, Mortar, and Grout1 (April)R 71-16 (2020)Sampling and Amount of Testing of Hydraulic Cement1 (April)STD. NO.TITLEGROUP(MONTH)JOINT FILLER AND ASPHALT PLANKM 33M/M 33-20Preformed Expansion Joint Filler for Concrete (Bituminous Type)2 (June)M 153-20Preformed Sponge Rubber, Cork, and Recycled Rubber Expansion Joint Fillers for ConcretePaving and Structural Construction2 (June)M 213-01 (2015)Preformed Expansion Joint Fillers for Concrete Paving and Structural Construction(Nonextruding and Resilient Bituminous Types)2 (June)M 251-06 (2020)Plain and Laminated Elastomeric Bridge Bearings2 (June)

STD. NO.TITLEGROUP(MONTH)JOINT FILLER AND ASPHALT PLANKM 297-10 (2015)Preformed Polychloroprene Elastomeric Joint Seals for BridgesR 50-09 (2018)Geosynthetic Reinforcement of the Aggregate Base Course of Flexible Pavement Structures2 (June)R 95-19Accelerated Aging of Hot-Poured Asphalt Crack Sealant Using a Vacuum Oven2 (June)STD. NO.TITLE2 (June)GROUP(MONTH)METALLIC MATERIALS FOR BRIDGESM 102M/M 102-06 (2016)Steel Forgings, Carbon and Alloy, for General Industrial Use2 (June)M 103M/M 103-12 (2016)Steel Castings, Carbon, for General Application2 (June)M 105-09 (2018)Gray Iron Castings2 (June)M 111M/M 111-15Zinc (Hot-Dip Galvanized) Coatings on Iron and Steel Products2 (June)M 163M/M 163-20Castings, Iron-Chromium, Iron-Chromium-Nickel, Corrosion Resistant, for GeneralApplication2 (June)M 169-20Steel Bars, Carbon and Alloy, Cold-Finished2 (June)M 202M/M 202-08 (2016)Steel Sheet Piling2 (June)M 227M/M 227-13 (2017)Steel Bars, Carbon, Merchant Quality, Mechanical Properties2 (June)M 232M/M 232-10 (2015)Zinc Coating (Hot-Dip) on Iron and Steel Hardware2 (June)M 255M/M 255-05 (2018)Steel Bars, Carbon, Hot-Wrought, Special Quality, Mechanical Properties2 (June)M 270M/M 270-20Structural Steel for Bridges2 (June)M 277-06 (2015)Wire Rope and Sockets for Movable Bridges2 (June)M 285M/M 285-11 (2015)Castings, Iron-Chromium-Nickel, Corrosion Resistant, for Severe Service2 (June)M 292M/M 292-20Carbon and Alloy Steel Nuts for Bolts for High-Pressure or High-Temperature Service, orBoth2 (June)M 314-90 (2018)Steel Anchor Bolts2 (June)M 334M/M 334-17Uncoated, Corrosion-Resistant, Deformed and Plain Chromium Alloyed, Billet-Steel Barsfor Concrete Reinforcement and Dowels2 (June)M 336M/M 336-20Steel Wire and Welded Wire, Plain and Deformed, for Concrete Reinforcement2 (June)STD. NO.TITLEGROUP(MONTH)MISCELLANEOUSM 143-14 (2018)Sodium Chloride2 (June)M 144-14 (2018)Calcium Chloride2 (June)M 230-07 (2020)Expanded and Extruded Foam Board (Polystyrene)2 (June)M 235M/M 235-13 (2018)Epoxy Resin Adhesives2 (June)M 333-20Detectable Warning Surfaces2 (June)R 8-96 (2019)Evaluation of Transportation-Related Earthborne Vibrations1 (April)STD. NO.TITLEGROUP(MONTH)PAINTING AND TRAFFIC MARKING AND SIGNINGM 224-91 (2019)Use of Protective Sealers for Portland Cement Concrete2 (June)

STD. NO.TITLEGROUP(MONTH)PAINTING AND TRAFFIC MARKING AND SIGNINGM 237-96 (2014)Epoxy Resin Adhesives for Bonding Traffic Markers to Hardened Portland Cement andAsphalt Concrete2 (June)M 247-13 (2018)Glass Beads Used in Pavement Markings2 (June)M 249-12 (2020)White and Yellow Reflective Thermoplastic Striping Material (Solid Form)2 (June)M 268-15Retroreflective Sheeting for Flat and Vertical Traffic Control Applications2 (June)M 300-03 (2017)Inorganic Zinc-Rich Primer2 (June)R 31-09 (2019)Evaluation of Protective Coating Systems for Structural Steel2 (June)R 98-20Determination of Size and Roundness of Glass Beads Used in Traffic Markings by Means ofComputerized Optical Method2 (June)STD. NO.TITLEGROUP(MONTH)PAVEMENT SURFACE AND STRUCTURE CHARACTERISTICSM 328-14 (2018)Inertial Profiler1 (April)M 331-17Smoothness of Pavement in Weigh-in-Motion (WIM) Systems1 (April)R 36-17Evaluating Faulting of Concrete Pavements1 (April)R 37-04 (2018)Application of Ground Penetrating Radar (GPR) to Highways1 (April)R 40-10 (2018)Measuring Pavement Profile Using a Rod and Level1 (April)R 43-13 (2017)Quantifying Roughness of Pavements1 (April)R 54-14 (2018)Accepting Pavement Ride Quality When Measured Using Inertial Profiling Systems1 (April)R 56-14 (2018)Certification of Inertial Profiling Systems1 (April)R 57-14 (2018)Operating Inertial Profiling Systems1 (April)R 85-18Quantifying Cracks in Asphalt Pavement Surfaces from Collected Pavement ImagesUtilizing Automated Methods1 (April)R 86-18Collecting Images of Pavement Surfaces for Distress Detection1 (April)R 87-18Determining Pavement Deformation Parameters and Cross Slope from Collected TransverseProfiles1 (April)R 88-18Collecting the Transverse Pavement Profile1 (April)STD. NO.TITLEGROUP(MONTH)QUALITY ASSURANCER 9-05 (2018)Acceptance Sampling Plans for Highway Construction1 (April)R 18-18Establishing and Implementing a Quality Management System for Construction MaterialsTesting Laboratories1 (April)R 20-99 (2017)Procedures for Measuring Highway Noise1 (April)R 38-10 (2018)Quality Assurance of Standard Manufactured Materials1 (April)R 42-06 (2020)Developing a Quality Assurance Plan for Hot Mix Asphalt (HMA)1 (April)R 61-12 (2020)Establishing Requirements for Equipment Calibrations, Standardizations, and Checks1 (April)R 65-14 (2018)Evaluating the Engineering and Environmental Suitability of Recycled Materials1 (April)

STD. NO.TITLEGROUP(MONTH)REINFORCING STEEL AND WIRE ROPEM 30-15Metallic-Coated Steel Wire Rope and Fittings for Highway Guardrail2 (June)M 31M/M 31-17Deformed and Plain Carbon and Low-Alloy Steel Bars for Concrete Reinforcement2 (June)M 54M/M 54-07 (2017)Welded Deformed Steel Bar Mats for Concrete Reinforcement2 (June)M 203M/M 203-20Steel Strand, Low-Relaxation Uncoated Seven-Wire for Concrete Reinforcement2 (June)M 204M/M 204-14 (2018)Uncoated Stress-Relieved Steel Wire for Prestressed Concrete2 (June)M 254-06 (2015)Corrosion-Resistant Coated Dowel Bars2 (June)M 275M/M 275-20Uncoated High-Strength Steel Bars for Prestressing Concrete2 (June)M 322M/M 322-10 (2015)Rail-Steel and Axle-Steel Deformed Bars for Concrete Reinforcement2 (June)M 329M/M 329-11 (2015)Stainless Clad Deformed and Plain Round Steel Bars for Concrete Reinforcement2 (June)STD. NO.TITLEGROUP(MONTH)SOILS AND STABILIZATIONM 57-80 (2017)Materials for Embankments and Subgrades3 (July)M 145-91 (2017)Classification of Soils and Soil–Aggregate Mixtures for Highway Construction Purposes3 (July)M 146-91 (2017)Terms Relating to Subgrade, Soil–Aggregate, and Fill Materials3 (July)M 147-17Materials for Aggregate and Soil–Aggregate Subbase, Base, and Surface Courses3 (July)M 216-13 (2017)Quicklime and Hydrated Lime for Soil Stabilization1 (April)M 288-17Geosynthetic Specification for Highway Applications2 (June)M 318-02 (2019)Glass Cullet Use for Soil–Aggregate Base Course3 (July)M 319-02 (2019)Reclaimed Concrete Aggregate for Unbound Soil–Aggregate Base Course3 (July)R 13-12 (2020)Conducting Geotechnical Subsurface Investigations3 (July)R 21-96 (2019)Drilling for Subsurface Investigations—Unexpectedly Encountering Suspected HazardousMaterial1 (April)R 22-97 (2015)Decommissioning Geotechnical Exploratory Boreholes1 (April)R 27-01 (2019)Assessment of Corrosion of Steel Piling for Non-Marine Applications3 (July)R 51-13 (2017)Compost for Erosion/Sediment Control (Filter Berms and Filter Socks)3 (July)R 52-10 (2019)Compost for Erosion/Sediment Control (Compost Blankets)3 (July)R 58-11 (2019)Dry Preparation of Disturbed Soil and Soil–Aggregate Samples for Test3 (July)R 69-20Determination of Long-Term Strength for Geosynthetic Reinforcement2 (June)R 74-16 (2020)Dry Preparation of Disturbed Soil and Soil–Aggregate Samples for Test3 (July)R 75-16 (2020)Developing a Family of Curves3 (July)STD. NO.TITLEGROUP(MONTH)TESTING EQUIPMENTM 152M/M 152-16 (2020)Flow Table for Use in Tests of Hydraulic Cement1 (April)M 201-15 (2020)Mixing Rooms, Moist Cabinets, Moist Rooms, and Water Storage Tanks Used in theTesting of Hydraulic Cements and Concretes1 (April)M 231-95 (2019)Weighing Devices Used in the Testing of Materials3 (July)M 261-18Rib-Tread Standard Tire for Special-Purpose Pavement Frictional-Property Tests1 (April)

STD. NO.TITLEGROUP(MONTH)TESTING EQUIPMENTM 286-18Smooth-Tread Standard Tire for Special-Purpose Pavement Frictional-Property TestsR 32-20Calibrating the Load Cell and Deflection Sensors for a Falling Weight Deflectometer1 (April)R 33-20Calibrating the Reference Load Cell Used for Reference Calibrations for a Falling WeightDeflectometer1 (April)R 45-13 (2017)Installing, Monitoring, and Processing Data of the Traveling Type Slope Inclinometer3 (July)STD. NO.TITLE1 (April)GROUP(MONTH)TIMBER AND PRESERVATIVESM 133-12 (2020)Preservatives and Pressure Treatment Processes for Timber2 (June)M 168-07 (2020)Wood Products2 (June)STD. NO.TITLEGROUP(MONTH)DELETED STANDARDSM 290-96 (2018)R 41-05 (2015)Acrylic Prismatic Reflectors and Embosse