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Sustainable Pavement Maintenance via Chip Sealing Application. Arya Ebrahimpour, Ph.D., P.E. Professor & Interim Chair Dept. of Civil and Environmental Engineering, Idaho State University. Outline. Introduction Laboratory Experiments Design Methodologies Test Results
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Sustainable Pavement Maintenance via Chip Sealing Application Arya Ebrahimpour, Ph.D., P.E. Professor & Interim Chair Dept. of Civil and Environmental Engineering, Idaho State University
Outline Introduction Laboratory Experiments Design Methodologies Test Results Conclusions and Recommendations
I. Introduction • Overview • Objectives • Scope of Work
1. Overview • What is Chip sealing? • Comparative Studies and success stories from round the world. • Cost effectiveness of chip sealing compared to other preventive maintenance techniques.
2. Objectives of the Research • To evaluate the effectiveness of Idaho’s existing chip seal practice. • To identify the reasons for the loss of aggregate from the pavement surface. • To study the materials used and suggest the best material to improve the chip seal practice. • To evaluate the performance of different kinds of binders. • To establish a better rational design method based on experiments performed in this project.
3. Scope of Work • Determine the properties of aggregate. • Utilize the parameters in design calcs. • Establish a better aggregate of the six districts of Idaho • Establishing a better rational design method which suites the conditions of Idaho.
II. Laboratory Tests • Sieve Analysis • Flakiness Index Test • Loose Unit Weight • Cleanliness Value Test • Vialit Tests
c) Loose Unit Weight Wt of Aggregate = 9.519 lb. Volume of the Container = 0.1 cubic feet. Loose Unit Wt = 9.519/ 0.1 = 95.19 lb/cubic feet
III. Design Methodologies • McLeod Design Method • Modified Kearby Method • New Zealand Chip Seal Design method • United Kingdom Road Note 39
1. McLeod Design Method The amount of aggregate is determined using the formula:
McLeod Design Method Cont’d Amount of binder to be used is given by:
2. Modified Kearby Method The amount of aggregate is determined by:
2. Modified Kearby Method The asphalt spread ratio is determined by:
3. New Zealand Chip Seals Method The residue asphalt content is determined:
4. United Kingdom Road Note 39 United Kingdom Road Note 39
IV. Results and Discussions • Median Size • Flakiness Index • Average Least Dimension • Loose Unit Weight • Void Ratio • Cleanliness Value Test • Vialit Test
1. Median Size of the Particle The median size varied from 0.242inches to 0.359 inches, the lowest for District 2 and the highest for District 1.
2. Flakiness Index Value The flakiness index values varied from 5.44 to 21.08, the lowest for District 5 and the highest for District 2.
4. Loose Unit Weight District 5 had the highest loose unit weight of 95.92 and District 6 had the least of 87.15.
7. Vialit Test Results The Vialit Tests
Vialit Test Results Cont’d • Vialit Test for Different Binders
Vialit Test Results Cont’d • Vialit Test Cured at different temperatures
Vialit Test Results Cont’d • The amount of aggregate swept for different binders
V. Conclusions and Recommendations • Conclusions • Recommendations
1. Conclusions • M/FI factor better than ALD • Void Ratio and its significance in the design. • Effect of fines on the aggregate retention • Effect of different binders on Aggregate retention.
Conclusions Cont’d • Effect of different aggregate on CRS-2R • Effect of temperature of curing on aggregate retention. • Cleanliness Value compared to Percentage fines.
2. Recommendations • Using washed aggregate or aggregate with least amount of fines is recommended. • Using aggregate which is more round in shape and is uniform in size are preferred.
Recommendations Cont’d • Quantities of binder and aggregate should be used as per calculated in the design method procedure. • Using Digital Imagery technique and Finite element analysis. • Wheel Tracking better than dropping a ball.