• dirty or contaminated;
• concrete;
• an exposed binder course following planing of an inadequate surface course; or
• an old hard, smooth asphalt surface.
• Loss of chippings
Plucking out due to lack of embedment or fretting of surface mortar.
A maintenance treatment can be designed, depending upon the mode of failure/problem exhibited. The following are typical treatments, together with the problems they solve:
The actual treatment undertaken will be determined based on all the factors involved and the time position on the life span of the asphalt surface.
Rolled asphalt is very tolerant of local patching and minor deficiencies can be easily remedied by a small patch properly executed. This would be done by hand, although anything in excess of 15 m long must be laid by machine.
5.7 ECONOMICS
The Institute of Asphalt Technology, in its video on Hot Rolled Asphalt, says that a properly specified, well-laid rolled asphalt should provide a maintenance free running surface for 15–20 years depending on traffic flows and underlying strength of pavement layers. It is against this background that the economics of using a tried and tested product must be viewed. Rolled asphalt with 35% 14 mm nominal size coarse aggregate with 20 mm pre-coated chippings having a polished stone value of 65 will typically cost £4.40/m2 at 1996 prices.
• Embedded chippings
Too much embedment at time of laying and movement of mortar around pre-coated chippings results in excess mortar at surface and low texture.
• Fretting Erosion of fines from the asphalt mortar under the actions of traffic.
Harder bitumen and higher void content may increase likelihood of fretting.
• Cracking This can take the form of crazing, transverse cracking, longitudinal cracking, edge cracking or reflection cracking at joints.
• Deformation Lost riding quality, wheel-track rutting, ponding of water or surface slippage.
• Lack of skidding
Resulting from a reduction in macro-texture of the resistance surface layer and/or micro-texture of the aggregates used.
• Visual appearance
A multi-patched surfacing, particularly with statutory undertakers’
works, may warrant treatment to restore the visual appearance.
• surface dressing—seal surface, restore skid resistance
• thin slurry—seal surface, restore skid resistance
• thick slurry—restore profile, restore skid resistance
• thin surface course—restore profile, restore skid resistance
• resurface2 (plane and replace)—remove brittle surface, restore profile, restore skid resistance
5.8 CONCLUSION
At a conference held in London in 1979 entitled The Performance of Rolled Asphalt Road Surfacing, the following summary was given:
The three themes of this Conference can be drawn together in the issues of control and specification. Each aspect demands more rigorous control of manufacture and laying. It is imperative to meet the increasing demands imposed by greater volumes of commercial traffic, in which the mean axle weight in the axle spectrum is increasing, if pavements are to fit their purpose.
The Department of Transport has increased the demands of its specification and is anxious to achieve end result drafting. However, improved control supervision is essential.
As the millennium approaches, the above statements currently apply to rolled asphalt.
Notes
5.9 REFERENCES
Annual Book of ASTM Standards. Volume 04.03, Road and Paving Materials; Pavement Management Technologies, American Society for Testing and Materials, Philadelphia.
ASTM D 2872–88, Standard Test Method for Effect of Heat and Air on a Moving film of Asphalt (Rolling Thin-film Oven Test) (ASTM D 2872).
Standard Methods for Analysis and Testing of Petroleum and Related Products, Institute of Petroleum, London. Breaking Point of Bitumen Fraass Method (IP 80)
Manual of Contract Documents for Highway Works, Her Majesty’s Stationery Office, London. Volume 1: Specification for Highway Works (MCHW 1). Volume 2: Notes for Guidance on the Specification for Highway Works (MCHW 2).
Design Manual for Roads and Bridges, Her Majesty’s Stationery Office, London. HD 26/94 Pavement Design (DMRB 7.2.3). HD 28/94 Skidding Resistance (DMRB 7.3.1).
Anon (1947) Highway Engineers’ Reference Book for County and Municipal Engineers, Civil Engineers and Contractors, George Newnes Ltd, London.
Attwooll, A.W. (1955) Rolled asphalt surfacing, Journal of the Institution of Highway Engineers 3(6), 59–75.
British Standards Institution (1928a) Single Coat Asphalt (Sand and Stone Aggregate).
BS 344:1928, British Standards Institution, London.
1. There is a proposal with the British Standards Institution to change from use of toluene to kerosene for health and safety reasons.
2. The plane and replace solution could utilize the recycling process for surface course ‘repave’.
British Standards Institution (1928b) Single Coat Asphalt (Clinker Aggregate). BS 345:
1928, British Standards Institution, London.
British Standards Institution (1928c) Two-Course Asphalt. BS 342:1928, British Standards Institution, London.
British Standards Institution (1935) Specification for Rolled Asphalt, Fluxed Lake Asphalt and Asphaltic Bitumen (Hot Process). BS 594:1935, British Standards Institution, London.
British Standards Institution (1945a) Rolled Asphalt, Asphaltic Bitumen and Fluxed Lake Asphalt (Hot Process); Part 1, Single Course. BS 594: Part 1:1945, British Standards Institution, London.
British Standards Institution (1945b) Rolled Asphalt, Asphaltic Bitumen and Fluxed Lake Asphalt (Hot Process); Part 2, Two Course. BS 594: Part 2:1945, British Standards Institution, London.
British Standards Institution (1950) Rolled Asphalt, Asphaltic Bitumen and Fluxed Lake Asphalt (Hot Process) . BS 594:1950, British Standards Institution, London.
British Standards Institution (1958) Rolled Asphalt, Asphaltic Bitumen and Fluxed Lake Asphalt (Hot Process). BS 594:1958, British Standards Institution, London.
British Standards Institution (1961) Rolled Asphalt Hot Process. BS 594:1961, British Standards Institution, London.
British Standards Institution (1973) Specification for Rolled Asphalt (Hot Process) for Roads and Other Paved Areas. BS 594:1973, British Standards Institution, London.
British Standards Institution (1983) Specification for Air-Cooled Blast-Furnace Slag Aggregate for Use in Construction. BS 1047:1983, British Standards Institution, London.
British Standards Institution (1984) Bitumen Road Emulsions (Anionic and Cationic);
Part 1, Specification for Bitumen Road Emulsions. BS 434: Part 1:1984, British Standards Institution, London.
British Standards Institution (1985a) Hot Rolled Asphalts for Roads and Other Paved Areas; Part 1, Specification for Constituent Materials and Asphalt Mixtures. BS 594 Part 1:1985, British Standards Institution, London.
British Standards Institution (1985b) Hot Rolled Asphalts for Roads and Other Paved Areas; Part 2, Specification for Transport, Laying and Compaction of Rolled Asphalt . BS 594 Part 2:1985, British Standards Institution, London.
British Standards Institution (1985c) Testing Aggregates; Part 103, Methods for the Determination of Particle Size Distribution; Section 103.1, Sieve Tests. BS 812: Part 103.1:1985, British Standards Institution, London.
British Standards Institution (1987) Road Aggregates; Part 1, Specification for Single-Sized Aggregate for General Purposes. BS 63: Part 1:1987, British Standards Institution, London.
British Standards Institution (1989a) Testing Aggregates; Part 103, Methods for the Determination of Particle Size Distribution; Section 103.2, Sedimentation Test. BS 812: Part 103.2:1989, British Standards Institution, London.
British Standards Institution (1989b) Testing Aggregates; Part 105, Methods for the Determination of Particle Shape; Section 105.1, Flakiness Index. BS 812: Part 105.1:
1989, British Standards Institution, London.
British Standards Institution (1989c) Testing Aggregates; Part 114, Method for the Determination of the Polished-Stone Value. BS 812: Part 114:1989, British Standards Institution, London.
British Standards Institution (1989d) Bitumens for Building and Civil Engineering; Part 1, Specification for Bitumens for Roads and Other Paved Areas. BS 3690: Part 1:1989, British Standards Institution, London.
British Standards Institution (1989e) Sampling and Examination of Bituminous Mixtures for Roads and Other Paved Areas; Part 102, Analytical Test Methods. BS 598: Part 102:1989, British Standards Institution, London.
British Standards Institution (1990a) Bitumens for Building and Civil Engineering; Part 3, Specification for Mixtures of Bitumen with Pitch, Tar and Trinidad Lake Asphalt. BS 3690: Part 3:1990, British Standards Institution, London.
British Standards Institution (1990b) Sampling and Examination of Bituminous Mixtures for Roads and Other Paved Areas; Part 105, Methods of Test for the Determination of Texture Depth. BS 598: Part 105:1990, British Standards Institution, London.
British Standards Institution (1990c) Sampling and Examination of Bituminous Mixtures for Roads and Other Paved Areas; Part 107, Method of Test for the Determination of the Composition of Design Wearing Course Rolled Asphalt. BS 598: Part 107:1990, British Standards Institution, London.
British Standards Institution (1990d) Sampling and Examination of Bituminous Mixtures for Roads and Other Paved Areas; Part 108, Methods for Determination of the Condition of the Binder on Coated Chippings and for Measurement of the Rate of Spread of Coated Chippings. BS 598: Part 108:1990, British Standards Institution, London.
British Standards Institution (1990e) Testing Aggregates; Part 113, Method for Determination of Aggregate Abrasion Value (AAV). BS 812: Part 113:1990, British Standards Institution, London.
British Standards Institution (1990f) Testing Aggregates; Part 111, Method for Determination of 10% Fines Value (TFV) . BS 812: Part 111:1990, British Standards Institution, London.
British Standards Institution (1992a) Hot Rolled Asphalts for Roads and Other Paved Areas; Part 1, Specification for Constituent Materials and Asphalt Mixtures. BS 594:
Part 1:1992, British Standards Institution, London.
British Standards Institution (1992b) Hot Rolled Asphalts for Roads and Other Paved Areas; Part 2, Specification for Transport, Laying and Compaction of Rolled Asphalt.
BS 594: Part 2:1992, British Standards Institution, London.
British Standards Institution (1993a) Method for Determination of the Indirect Tensile Stiffness Modulus of Bituminous Mixtures. DD 213:1993, British Standards Institution, London.
British Standards Institution (1993b) Petroleum and its Products; Part 45, Loss on Heating Bitumen and Flux Oil. BS 2000: Part 45:1993, British Standards Institution, London.
British Standards Institution (1993c) Petroleum and its Products; Part 47, Solubility of Bituminous Binders. BS 2000: Part 47:1993, British Standards Institution, London.
British Standards Institution (1993d) Petroleum and its Products; Part 49, Penetration of
Bituminous Materials. BS 2000: Part 49:1993, British Standards Institution, London.
British Standards Institution (1993e) Petroleum and its Products; Part 58, Softening Point of Bitumen (Ring and Ball) . BS 2000: Part 58:1993, British Standards Institution, London.
British Standards Institution (1993f) Petroleum and its Products; Part 72, Viscosity of Cutback Bitumen. BS 2000: Part 72:1993, British Standards Institution, London.
British Standards Institution (1995) Testing Aggregates. Part 2: Methods for Determination of Density. BS 812: Part 2:1995, British Standards Institution, London.
British Standards Institution (1996a) Sampling and Examination of Bituminous Mixtures for Roads and Other Paved Areas; Part 110, Method of Test for the Determination of Wheel-Tracking Rate. BS 598: Part 110:1996, British Standards Institution, London.
British Standards Institution (1996b) Method of Test for Determining Resistance to Permanent Deformation of Bituminous Mixtures Subject to Unconfined Dynamic Loading. DD 226:1996, British Standards Institution, London.
Cooper, K.E. and S.F.Brown (1995) Assessment of the mechanical properties of asphaltic mixes on a routine basis using simple equipment, The Asphalt Yearbook 1995, The Institute of Asphalt Technology, Staines, 35–40.
County Surveyors Society (1994) Pavement Design Manual, Eng/6–94, Wiltshire County Council.
Daines, M.E (1992) The Performance of Hot Rolled Asphalt Containing Crushed Rock Fines, A303 Mere, Department of Transport TRL Research Report 298, Transport Research Laboratory, Crowthorne.
Daines, M.E. (1995) Tests for Voids and Compacting in Rolled Asphalt Surfacing.
Department of Transport TRL Project Report 78, Transport Research Laboratory, Crowthorne.
Denning, J.H. and J.Carswell (1981) Improvements in Rolled Asphalt Surfacings by the Addition of Organic Polymers, Department of the Environment Department of Transport TRRL Laboratory Report 989, Transport and Road Research Laboratory, Crowthorne.
Energy Efficiency Office (1990) The Use of Pulverised Fuel Ash as a Bituminous Filler.
R&D Profile 52, Energy Efficiency Enquiries Bureau, Harwell.
Hill, J. (1983) Economic use of bituminous materials. Journal of the Institution of Highway Engineers, Jan.
Hunter, R.N. (ed.) (1994) Bituminous Mixtures in Road Construction, Thomas Telford, London.
Nicholls, J.C. (1994) Generic Types of Binder Modifier for Bitumen, SCI Lecture Paper No. 0035, Society of Chemical Industry, London.
Nicholls, J.C. and M.E.Daines (1993) Acceptable Weather Conditions for Laying Bituminous Materials, Department of Transport TRL Project Report 13, Transport Research Laboratory, Crowthorne.
Nunn, M.E. (1989) An investigation of reflection cracking in composite pavements in the United Kingdom. Proceedings of the Conference on Reflective Cracking in Pavements, Liege, 146–53.
Nunn, M.E. and T.Smith (1994) Evaluation of a Performance Specification in Road Construction, Department of Transport TRL Project Report 55, Transport Research Laboratory, Crowthorne.
Richardson, C. (1905) The Modern Asphalt Pavement, John Wiley & Sons Inc., New York.
Road Research Laboratory (1952) Recommendations for Bituminous Surfacings for Roads Carrying Tracked Vehicles, Department of Scientific and Industrial Research Road Note 13, Her Majesty’s Stationery Office, London.
Spielmann, P.E. and A.C.Hughes (1936) Asphalt Roads, Edward Arnold & Co. Ltd, London.
Surrey County Council (1995) Term Tender 1, Surrey County Council, Guildford.
Szatkowski, W.S. and F.A.Jacobs (1977) Dense wearing courses in Britain with high resistance to deformation, Colloquium 77, Plastic Deformability of Bituminous Mixes, Zurich, 65–7.