Longer Service Life of Pavement

Transcription

1 Technical Seminar on Road Transportation Infrastructure for ASEAN Integration Pavement session Longer Service Life of Pavement - From Design up to Maintenance - Satoshi MIZUNO Group Manager Department of International June 13th, 2016

2 Profile of Satoshi MIZUNO Professional Engineer (Japan) in Civil Engineering (Road Planning) Engaged in road and highway design Graduated from Civil Engineering Course of Meijo University, Japan, in 1989 Experience of Consultant engineer for 27 years Major Projects: Nairobi Viaduct and Road Construction Project (PM) Nacala Corridor Road Improvement Project (320km) (PM) Basic Research on the Pavement Design & Construction (PM) Kampala Flyover Improvement Project (D/PM) Mazār-e Sharīf Road Improvement Project (Road Design) East coast area Road Rehabilitation in Sri Lanka (Highway Design) Page 2

3 Contents of Presentation 1. Our Experience 2. Quality Assurance 3. Applicable New Technology 4. Trend of Pavement Design Method Page 3

4 1. Our Experience (Premature Failure & Distress) Flow Rutting & Corrugation (Mountainous Area) Flow Rutting & Pothole (Urban Area) Page 4

5 1. Our Experience (Premature Failure & Distress) Flow Rutting & Bleeding (Rural Area) Others Slipping Distress on cemented base Uneven Page 5

6 1. Our Experience (Premature Failure & Distress) What causes these unexpected damage? Pavement Composition Subgrade Capacity (e.g. CBR) It arises from an imbalance in these structure Expected Axle load Page 6

7 1. Our Experience (Premature Failure & Distress) What is happening at Site? Pavement structure design and mix-design don t balance (unmatching) with site condition. Specifically The most considerable points: Climate condition Traffic condition Material quality and procurement condition Page 7

8 1. Our Experience (Premature Failure & Distress) HOT-MIX ASPHALT TROUBLE SHOOTING GUIDE in South Africa SABITA (Southern African Bitumen. Association) has been publishing Ttrouble Shooting Guide for prevention of a trouble on hot-mix asphalt at site. PROBLEM POSSIBLE CAUSES Pr. Im. SUGGESTED SOLUTIONS Rutting: Deformation in wheel tracks under traffic (often accompanied by bleeding). 1. Bitumen: 1. Bitumen: a. Too soft for the application. M H a. Use correct grade or modify for ambient temps and traffic. b. Contaminated, causing softening. L H b. Check properties of samples from mixing plant. c. Compositional balance of c. Check for compliance with specs, but note that spec tolerances are wide. bitumen. L H Can be big differences in properties of bitumen of same penetration grades. 2. Asphalt Design: 2. Asphalt Design: Note: Any mix revisions suggested below must ensure that design requirements for the job are still met. a. Bitumen content too high. H H a. Revise design for stiffer mix. b. Very rounded aggregates. L M b. Change aggregate source if possible and practical. c. Grading close to maximum density line. d. High filler content acting as a bitumen extender. (causing excess mastic). e. Filler/binder ratio too low, causing tender mix. M M M M c. Revise grading curve to achieve a harsher mix. H d. Check filler properties; redesign mix with reduced filler and suitable VIM's. (But see 2e below for the opposite effect of another type of filler). H e. Increase filler content but don't make mix uncompactable. Note: This filler is doing the opposite of fillet in 2d above. Page 8

9 1. Our Experience (Premature Failure & Distress) Rutting: Deformation in wheel tracks under traffic (often accompanied by bleeding). 3. Asphalt mixing and transport: 3. Asphalt mixing and transport: a. Contamination in plant (unburnt fuel etc). L H a. Check temperatures, air feed, burners, nozzles, fuel quality. b. Excess release agent in hot bins. L M b. Consider use ofnon oil-based release agent. c. Excess release agent (diesel?) on trucks. L M c. Consider use ofnon oil-based release agent. 4. Construction: 4. Construction: a. Excessive release agent (diesel?) in paver hopper. L L a. Consider use of non oil-based release agent. b. Over-compaction (only if mix VIM's are too low). L H b. Rather revise the mix design than reduce compaction effort. c. Very high ambient temperatures. H H c. Consider using a stiffer or modified bitumen. 5. General: 5. General: a. Heavy traffic or a. Re-design a rut resistant mix (maybe with stiffer or modified accelerating/decelerating traffic H H bitumen) but make sure it is still compactable. (at intersections). b. Fuel and/or oil spills from traffic H M b. Repair. Note that EVA modified asphalt is resistant to these spills. The Probability (Pr) of the problem's occurrence is indicated in the central column, with probability rated High (H), Medium (M), Low (L). The Impact (lm) on final product is shown in the central column, evaluated as High (H), Medium (M), or Low (L). HOT-MIX ASPHALT TROUBLE SHOOTING GUIDE: Society for Asphalt Technology April 2005 Page 9

10 2. Quality Assurance How do we ensure pavement quality? Quality control during the construction phase is generally based on a dual control system where both the contractor, and the supervising consulting engineer, have specific responsibilities and contractual obligations. Quality Management (Contractor) Prevents problems Does the right thing Controls activity Involves all people in the organization Places responsibility for quality with the people who do the work Quality Control (Engineer) Reacts to problems Does the right thing Provides end inspection Places reliance on quality control specialist Client supervision Page 10

11 2. Quality Assurance The various phases of quality control are summarized as follows: Component materials Conformance to standards Materials design: Laboratory Material quality Design parameters Design verification: Trial section Construction processes Material quality Design parameters Constructed layer control Construction process Material quality Design parameters Page 11

12 2. Quality Assurance The responsibilities of the consultant engineers cover a wide range of activities, including aspects such as: Knowledge of project requirements and specifications Evaluate of raw materials properties Materials selection and utilisation Assess of materials design properties and sensitivity to changes and variations Suitability of construction plant Appropriateness and consistency of construction processes and techniques Adhere to prescribed environmental limitations, e.g., weather and temperature Visually inspect completed elements Test materials properties in place Level, width and layer thickness control Smoothness and surface finish Report results and final assessment of completed work Knowledge of laboratory quality and auditing procedures Page 12

13 3. Applicable New Technology Why is a longer service life of pavement required? Social requirement and pressure in JAPAN Increase of infrastructures stock Increase of rehabilitation & maintenance cost Strong requirement to a longer service life using new technology such as recycling Waste disposal Rationalized construction works Economical construction works Efficient use of existing resources A longer service life is strongly required together with development of new technology such as recycling. Page 13

14 3. Applicable New Technology Why is a tough pavement required? Change of traffic conditions in ASEAN - Economic growth, - Higher traffic volumes, - Higher axle loads, - Higher tyre pressures, - Need for sustainable use of resources, - Conventional design concepts still suitable? How do we realize a longer service life of pavement and a tough pavement? Page 14

15 3. Applicable New Technology Utilization of modified binders or anti-rutting additive is the most easy way. It is especially developed to resist the rutting of hot mix asphalt wearing course. It has the advantages of high temperature stability, fatigue resistance performance, water stability and the low temperature crack resistance. It can be applied to various of asphalt mixture and greatly improve the performance of asphalt mixture. Modified binders tends to be significantly more expensive than neat, or unmodified, asphalts. Material costs alone could be 25 to 100% higher than conventional asphalts. Construction costs could also be increased due to the need for higher temperatures, additional equipment and other special handling requirements. These additional costs made it harder to justify the use of modified binders without reliable performance histories. The need for innovation Page 15

16 3. Applicable New Technology 3-1. HiMA(High modulus asphalt) Origin: France early 90s, Enrobés à Module Elevé (EME) Typical characteristics: High binder content 6% by mass of aggregate, Hard binder: Pen 10-25, Low air voids content, High Modulus High resistance against permanent deformation, Good fatigue resistance, Impermeable, Increased mixing temperature. Average base layer thickness reduction of 30% Less maintenance = less road user delays, Less emissions & less us of non-renewable materials Page 16

17 3. Applicable New Technology 3-3. Recycling Technology Outline In-situ Base course Recycle The cold stabilization method using cement and/or asphalt is applied to all parts of the world. It is excellent for saving energy and natural resources. The stabilization method using cement and/or asphalt mainly is applied to recycling base course in-situ. Aggregate Recycling Aggregate recycling will reduces the demand for virgin aggregates from pits and quarries. And it also reduces the amount of waste going to landfill due to reusing aggregates. In addition, in many cases, recycled aggregates cost is less than virgin aggregates. Engineering When it was compacted by rolling equipment, strength in the mechanism rises. Hence, it will keep good stability and durability. Quality of pavement will depend on quality of recycling aggregates. If quality is low, premature failures will be occurred. Environmental Construction It contributes to saving construction material resources and energy and reducing CO2 emissions. Hence it is environmentally acceptable. Period of the pavement works is the shortest among these. Hence impact to traffic during construction will be alleviated. It contributes to saving construction material resources and energy and reducing CO2 emissions. Hence it is environmentally acceptable. Period of the pavement works will be same as reconstruction work. Page 17

18 3. Applicable New Technology 3-3. Stabilising with Foamed Asphalt (recycling on site) Cement stabilization and asphalt stabilization with cement are used as major recycling method in-situ. CFA (Cement Foamed Asphalt) is one of new technology for the asphalt stabilization with cement. CFA utilizes formed asphalt (normal asphalt with or of penetration grade). Strength of CFA is higher than other methods as below. And the asphalt stabilization base has a high resistibility against water because aggregate and soil are solidly bound by cement and asphalt. So CFA is more suitable for existing road rehabilitation. Asphalt Layer (as a reference) Cement Stabilization Granular (CBR>80) CFA Structure Number Page 18

19 3. Applicable New Technology 3-3. Stabilising with Foamed Asphalt Page 19

20 3. Applicable New Technology 3-4. Asset Management Pavement management systems take on a variety of forms, with varying complexity. An essential element of a modern PMS is a well-integrated database in which to store the road definitions and the related data. Software for PMS World Bank: HDM-4 (world standard, Pavement plan and analysis) ADB: RoSy (Pavement plan and analysis together with GIS + Data base) In Japan Each local government developed own PMS System. Kyoto Model is representative of PMS in Japan. Kyoto Model has high affinity with PDCA(PLAN DO Check - Action) cycle for pavement management. Page 20

21 3. Applicable New Technology 3-4. Asset Management Whole Structure of Kyoto Model Pavement Management System Source: Estimation for Pavement Performance Curve based on Kyoto Model : A Case Study for Highway in the State of Sao Paulo Page 21

22 3. Applicable New Technology 3-4. Asset Management Example of Integrated PMS showing Map and Individual Data in South Africa Page 22

23 3. Applicable New Technology 3-4. Asset Management Surveillance Devices Integrated Surveillance Device Under Development It is possible to obtain necessary data with high-speed (80km/h or more) Page 23

24 3. Applicable New Technology 3-5. Weigh-in-motion Weigh-in-motion (WIM) devices are set to capture and record truck axle weights and gross vehicle weights as they drive over a sensor. Gross vehicle and axle weight monitoring is useful for weight measurement and classification. Example of an Axle Load Histogram Page 24

25 3. Applicable New Technology 3-6. Conventional and novel method (BAILEY METHOD) Current asphalt mix design methods lack guidance in: Selection of design aggregate structure Relationship between aggregate structure and mixture volumetric properties What does it take? Rut Resistance Coarse aggregate skeleton locked together with strong fine aggregate and high stiffness binder. Fatigue Resistance Thick stiff layer with sufficient asphalt binder Durability Low air voids in moisture resistant mixture Page 25

26 3. Applicable New Technology 3-6. Conventional and novel method (BAILEY METHOD) Page 26

27 4. Trend of Pavement Design Method Major pavement design methods Methods Logic Representative Empirical methods (Over-design, over-spec) based on observations of the performance of pavements. JP Standard (T A Method) AASHTO 1993 (Still major) Mechanistic methods which analyse the pavement as a mechanism, and link mechanistic parameters to the structural capacity. Austroads (Trunk road) Mechanistic-empirical methods Catalogues (Over-design, over-spec) which analyse the pavement as a mechanism, and link mechanistic parameters to the structural capacity through empirical observations of performance. with standard designs for general conditions. These are developed either empirically or using ME methods, or a combination of both. MEPD (AASHTO) SAMDM (South Africa) JP Standard TRH4 SATCC Road Note Austroads (low volume) Performance based which specify the pavement performance such as noise reduction, etc. JP Standard Page 27

28 4. Trend of Pavement Design Method Empirical-theoretical pavement design Item Japan Republic of South Africa Design Method multi-layer elasticity theory SA Mechanistic Pavement Design Method Software GAMEs + Excel MePAD (MeGAMEs, December 2016) Input Distress Formula Specialty Remarks Resilient modulus, Tyre Pressure Hot mix asphalt fatigue Fatigue of surfacing layers Fatigue of base layers Subgrade permanent deformation Modified AI formula (consideration of JP experience) Refection of temperature to resilient modulus of asphalt layer Resilient modulus, Tyre Pressure, Climate (wet/dry) Traffic Class Hot mix asphalt fatigue Fatigue of thin (< 50 mm thick) surfacing layers: continuously and gap-graded Fatigue of thick (> 75 mm thick) base layers Subgrade permanent deformation Unbound granular base and subbase layer Permanent deformation Cemented base and subbase layers Crushing failure Effective fatigue Permanent deformation Mechanistic design method become major player instead of empirical method i.e. AASHTO In the USA, a mechanistic-empirical design guide has been developed by AASHTO for all typical pavement types. The method is also known as NCHRP 1-37, and was published in The method is complex, and needs to be calibrated for climatic areas and specific projects. The method utilises a recursive procedure, to calculate the deterioration over the life of the pavement. Page 28

29 4. Trend of Pavement Design Method Empirical-theoretical pavement design Analysis Positions for Critical Parameters Page 29

30 4. Trend of Pavement Design Method Next Stage on Pavement Design Methods Description Reliability Empirical methods Mechanistic-empirical methods Mechanistic-empirical - probability methods Over-spec/over-design and not fit to material resource and quality High-cost Introduce of Material elastic modulus, Poisson ratio Climate (temperature, wet/dry) Traffic (Tyre pressure, traffic class) Output engineering parameters such as stresses and strains Number of axle or wheel up to Fatigue failure Introduce of: Viscoelastic logic Deterioration model based on obtained actual data Tyre s shape (single wide tyre) Traffic axle load spectrum from weigh-in-motion system Output Pavement composition with recommended material Asphalt mix Pavement performance curve Economic evaluation High Middle (Input data for material model is insufficient) Unknown Page 30

31 4. Trend of Pavement Design Method What is pavement structure design? The key for selection of materials and decision of layer thickness is to consider balance. (e.g. cemented sub-base performs as good construction platform, but it depends on material quality.) CSIR Dr. Morris De Beer The most important things to the pavement structure design and asphalt mixdesign are to pay attention to environmental (climate and material) condition and traffic condition. Pretoria University Dr. James Maina Page 31

32 Thank you for your kind attention Please contact me if there are any question! Satoshi MIZUNO Department of International Page End