defects in road
DESCRIPTION
Defects in RoadTRANSCRIPT
![Page 1: Defects in Road](https://reader033.vdocuments.us/reader033/viewer/2022061610/577c834f1a28abe054b47a3b/html5/thumbnails/1.jpg)
In the name of Allah, who is most merciful & most gracious.
![Page 2: Defects in Road](https://reader033.vdocuments.us/reader033/viewer/2022061610/577c834f1a28abe054b47a3b/html5/thumbnails/2.jpg)
Reflection cracks.
Hafiz Junaid Mushtaq2012-BT-Civil-24
Hafiz Muhammad Nadir Ali2012-BT-Civil-11
![Page 3: Defects in Road](https://reader033.vdocuments.us/reader033/viewer/2022061610/577c834f1a28abe054b47a3b/html5/thumbnails/3.jpg)
Reflection cracks.Hafiz Muhammad Nadir Ali2012-BT-Civil-11
Reflection cracks.
![Page 4: Defects in Road](https://reader033.vdocuments.us/reader033/viewer/2022061610/577c834f1a28abe054b47a3b/html5/thumbnails/4.jpg)
Concrete joints reflected through bituminous overlay.
Reflection cracksCracks in overlays reflect the crack pattern in the pavement underneath. They are difficult to prevent and correct. Thick overlays or reconstruction is usually required.
![Page 5: Defects in Road](https://reader033.vdocuments.us/reader033/viewer/2022061610/577c834f1a28abe054b47a3b/html5/thumbnails/5.jpg)
Cracks in a flexible overlay over an existing crack or joint. The cracks occur directly over the underlying cracks or joints. “Joint reflection cracking” specifically refers to reflection cracks arising from underlying PCC pavement joint movement. Reflection cracks can also occur over existing cement or lime stabilized base, etc
![Page 6: Defects in Road](https://reader033.vdocuments.us/reader033/viewer/2022061610/577c834f1a28abe054b47a3b/html5/thumbnails/6.jpg)
![Page 7: Defects in Road](https://reader033.vdocuments.us/reader033/viewer/2022061610/577c834f1a28abe054b47a3b/html5/thumbnails/7.jpg)
Background.
Reflective cracks are caused by discontinuities in the underlying layers which propagate through the HMA surface due to movement at the crack.
Most common in asphalt overlays placed on rigid pavements.
Also occurs in asphalt overlays on cracked asphalt concrete pavements;
Also in asphalt pavements with stabilized bases.
![Page 8: Defects in Road](https://reader033.vdocuments.us/reader033/viewer/2022061610/577c834f1a28abe054b47a3b/html5/thumbnails/8.jpg)
Types of reflective cracking
Double reflective crackingSingle reflective cracking
![Page 9: Defects in Road](https://reader033.vdocuments.us/reader033/viewer/2022061610/577c834f1a28abe054b47a3b/html5/thumbnails/9.jpg)
The opening and closing of the joint or crack.
temperature variations caused thermal stress and induces cracking initiation.
traffic loading and associated stress play a role in the second step of propagation.
Mechanisms of Single Reflective Cracking.
![Page 10: Defects in Road](https://reader033.vdocuments.us/reader033/viewer/2022061610/577c834f1a28abe054b47a3b/html5/thumbnails/10.jpg)
![Page 11: Defects in Road](https://reader033.vdocuments.us/reader033/viewer/2022061610/577c834f1a28abe054b47a3b/html5/thumbnails/11.jpg)
Prevention.Design asphalt mixtures with higher cracking resistance.
Increase overlay thickness.
Use a modified overlay mix.
Modifying existing pavement prior to overlay construction.
Use of interlayer to reduce stresses and inhibit cracks.
![Page 12: Defects in Road](https://reader033.vdocuments.us/reader033/viewer/2022061610/577c834f1a28abe054b47a3b/html5/thumbnails/12.jpg)
Geogrid System.
Reflective crack in Washington
![Page 13: Defects in Road](https://reader033.vdocuments.us/reader033/viewer/2022061610/577c834f1a28abe054b47a3b/html5/thumbnails/13.jpg)
Geogrid in pavement System
Primary function is reinforcement through• Lateral restraint.• Improved Bearing capacity.• Tension membrane effect.• Reduced cost by reducing pavement structure thickness and
increases pavement life.
![Page 14: Defects in Road](https://reader033.vdocuments.us/reader033/viewer/2022061610/577c834f1a28abe054b47a3b/html5/thumbnails/14.jpg)
Geogrid enhances:• Stiffness and resiliency of aggregate and granular fill• Load distribution• Rutting resistance under repeated loads• Bearing capacity and settlement resistance• Separation of dissimilar soils
Geogrids for Roadway Applications
![Page 15: Defects in Road](https://reader033.vdocuments.us/reader033/viewer/2022061610/577c834f1a28abe054b47a3b/html5/thumbnails/15.jpg)
Function and PerformanceGeogrids
Improved Bearing Capacity.
![Page 16: Defects in Road](https://reader033.vdocuments.us/reader033/viewer/2022061610/577c834f1a28abe054b47a3b/html5/thumbnails/16.jpg)
![Page 17: Defects in Road](https://reader033.vdocuments.us/reader033/viewer/2022061610/577c834f1a28abe054b47a3b/html5/thumbnails/17.jpg)
![Page 18: Defects in Road](https://reader033.vdocuments.us/reader033/viewer/2022061610/577c834f1a28abe054b47a3b/html5/thumbnails/18.jpg)
![Page 19: Defects in Road](https://reader033.vdocuments.us/reader033/viewer/2022061610/577c834f1a28abe054b47a3b/html5/thumbnails/19.jpg)
Case HistorySalo Road Washinton D.C
![Page 20: Defects in Road](https://reader033.vdocuments.us/reader033/viewer/2022061610/577c834f1a28abe054b47a3b/html5/thumbnails/20.jpg)
![Page 21: Defects in Road](https://reader033.vdocuments.us/reader033/viewer/2022061610/577c834f1a28abe054b47a3b/html5/thumbnails/21.jpg)
![Page 22: Defects in Road](https://reader033.vdocuments.us/reader033/viewer/2022061610/577c834f1a28abe054b47a3b/html5/thumbnails/22.jpg)
![Page 23: Defects in Road](https://reader033.vdocuments.us/reader033/viewer/2022061610/577c834f1a28abe054b47a3b/html5/thumbnails/23.jpg)
![Page 24: Defects in Road](https://reader033.vdocuments.us/reader033/viewer/2022061610/577c834f1a28abe054b47a3b/html5/thumbnails/24.jpg)
![Page 25: Defects in Road](https://reader033.vdocuments.us/reader033/viewer/2022061610/577c834f1a28abe054b47a3b/html5/thumbnails/25.jpg)
![Page 26: Defects in Road](https://reader033.vdocuments.us/reader033/viewer/2022061610/577c834f1a28abe054b47a3b/html5/thumbnails/26.jpg)
![Page 27: Defects in Road](https://reader033.vdocuments.us/reader033/viewer/2022061610/577c834f1a28abe054b47a3b/html5/thumbnails/27.jpg)
![Page 28: Defects in Road](https://reader033.vdocuments.us/reader033/viewer/2022061610/577c834f1a28abe054b47a3b/html5/thumbnails/28.jpg)
![Page 29: Defects in Road](https://reader033.vdocuments.us/reader033/viewer/2022061610/577c834f1a28abe054b47a3b/html5/thumbnails/29.jpg)
![Page 30: Defects in Road](https://reader033.vdocuments.us/reader033/viewer/2022061610/577c834f1a28abe054b47a3b/html5/thumbnails/30.jpg)
![Page 31: Defects in Road](https://reader033.vdocuments.us/reader033/viewer/2022061610/577c834f1a28abe054b47a3b/html5/thumbnails/31.jpg)
![Page 32: Defects in Road](https://reader033.vdocuments.us/reader033/viewer/2022061610/577c834f1a28abe054b47a3b/html5/thumbnails/32.jpg)
![Page 33: Defects in Road](https://reader033.vdocuments.us/reader033/viewer/2022061610/577c834f1a28abe054b47a3b/html5/thumbnails/33.jpg)
That’s It. Thanks for your Attention.