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Slide 1 of 34 By Shahin Shabani Transportation Research Institute (TRI) Tehran- Iran Presented on...
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Transcript of Slide 1 of 34 By Shahin Shabani Transportation Research Institute (TRI) Tehran- Iran Presented on...
Slide 1 of 34
ByShahin Shabani
Transportation Research Institute (TRI)Tehran- Iran
Presented on May 16
3rd International Road Surface Friction conferenceSafer Road Surface – Saving lives
Effect of Aggregate Arrangement onIncreasing frictional Resistance Through
Blending of Stone Material
Slide 2 of 34Slide 1 of 18
Presentation Outline
2011/05/16
o Introductiono Problem Statement and Main Objectiveso General Work Plano Experimental Procedure
o Preparation of Specimenso Testing Process
o Results and Discussiono Conclusions
Slide 3 of 34Slide 2 of 182011/05/16
Introduction
Road Surface
Friction
Factor 1
Factor 2Factor 3 Factor i
Surface Characteristics
Macrotexture Microtexture
Slide 4 of 34Slide 3 of 182011/05/16
• Microtexture: function of surface texture of aggregate particles
• Microtexture is Polished under traffic action
Introduction
Polishing
Loss of Microtexture
Slide 5 of 34Slide 5 of 182011/05/16
The ability of different aggregates to resist polishing is measured by PSV index in Lab
Standard BS EN 1097
There are 3 Categories of Aggregates:HPA (PSV≥60)MPA (50≤PSV<60)LPA (PSV<50)
Introduction
Slide 6 of 34Slide 6 of 18
Problem Statement and Main Objectives
2011/05/16
The most common rocks being used for road construction are the carbonate rocks
This group of rocks has low hardness and resistance to abrasion and polishing
carbonate aggregates are among LPA
The usage of LPA must be limited in the wearing surfaces
Slide 7 of 34Slide 6 of 18
Problem Statement and Main Objectives
2011/05/16
One way to improve would be in blending two or more types of aggregates with different PSV’s.
Research objective:Finding the best arrangement of two aggregates for achieving the maximum skidding resistance
in the laboratory scale.
Aggregate blending was studied in great detail by Ohio Department of Transportation(Liang 2003).
Slide 8 of 34Slide 7 of 18
Mechanism of Polishing
Two mechanism can occur during an aggregate polishing process:
A general polishing, which tends to remove materials
A differential polishing, which tend to create relief between soft and hard minerals.
2011/05/16
Slide 9 of 34Slide 8 of 18
General Work Plan
Collection of Limestone Aggregate
Collection of Basalt Aggregate
Preparation of Aggregates for polishing test
Preparation of test specimens for mounting on the APM ( 50/50 blend of Limestone and Basalt)
Accelerated Polishing of Aggregates Using the APM
Measurement of Friction Number Using the British Pendulum Tester
Determination of PSV Standard BS EN1097
Conclusions and Recommendations
2011/05/16
Slide 10 of 34Slide 9 of 18
A B C D E F Lime Stone Basalt
Description Designation Description DesignationLongitudinal
GroupRegular arrangement
DTransverse
GroupRegular arrangement
A
LongitudinalNon group
Regular arrangementE
TransverseAlternate
Non groupRegular arrangement
B
Irregular
RandomF
TransverseAlternate
Non groupRegular arrangement
C
2011/05/16
Experimental ProcedurePreparation of specimens
Slide 11 of 34Slide 10 of 182011/05/16
(1) (2) (3) (4)
(5) (6) (7) (8)
Experimental ProcedurePreparation of specimens
Slide 12 of 34Slide 7 of 50Slide 11 of 182011/05/16
A B C D E F Lime Stone Basalt
Experimental ProcedurePreparation of specimens
Slide 13 of 34Slide 12 of 182011/05/16
Experimental ProcedureTesting Procedure
Slide 14 of 34
Experimental ProcedureTesting Procedure
Slide 15 of 34Slide 14 of 18
Results and DiscussionPSV for different specimens
2011/05/16
Slide 16 of 34Slide 14 of 18
Results and DiscussionPSV for different specimens
2011/05/16
Slide 17 of 34Slide 15 of 182011/05/16
Summery and Conclusions
Aggregate arrangement affects friction resistance; the highest change in PSV (about 7 units) has been obtained in this blending.
Transversal alternative arrangement of aggregates provides a better condition for the creation of a new texture.
The least friction is obtained when aggregates are placed in the specimens irregularly and randomly; this is usually the case.
Slide 18 of 34Slide 16 of 182011/05/16
Summery and Conclusions
The best aggregate blending arrangement, with a different abrasion property, is achieved when aggregates are arranged regularly and also the conditions have been provided for the creation of a new texture.
The least friction reduction, during the test period, has been found from specimens with alternative non group regular arrangements.
Slide 19 of 34Slide 17of 182011/05/16
Acknowledgements
Friends who helped during this research
Sponsors of this research
Iran University of Science and Technology (IUST)
Transportation Research Institute (TRI)
Slide 20 of 34Slide 18 of 182011/05/16
Thank you for your attention