5 Causes of Shoving and Rutting
Shoving and rutting is the bulging and rippling of the pavement surface. It occurs at points where a vehicle pulls its brakes or at points where pavement meets rigid objects. It is usually caused by:
1. Weak Sub-grade Conditions
When constructing flexible pavement, poor soil subgrade will lead to problems like shoving. Subgrade soil is weak if it contains a lot of plastic clays, organic soil etc. A water table that is close to the location of the subgrade soil will also make it weak and unable to take loads.
Generally, the weak soil is excavated and is replaced with boulders and crushed stones to stabilise the subgrade course. If the depth of excavation is not up to standard, then the stones and boulders may sink which leads to the formation of ripples on the pavement surface.
2. Improper Rolling
During construction, the improper rolling of flexible pavement will result in some layers that are not properly held together at certain places. So, whenever traffic enters, those weaker layers get disrupted which leads to the formation of ripples on the pavement.
3. Poor Mixing
Defective mixing of surface course in flexible pavement will lead to shoving. It may even spread to larger areas from the continuous flow of traffic or vehicular movement.
4. Temperature effect
Bitumen is used on flexible pavement surfaces. The viscous state of bitumen mean that it will vary according to the temperature. Therefore, its temperature should be maintained during mixing and rolling to achieve maximum stability after drying. Extremely high temperatures at any stage of this process will reduce the pavement’s stability and lead to waves forming during compacting.
5. Weak bottom layers
When those layers are subjected to repeated vehicular movements, the surface course will become deformed and depressed, and this will eventually lead to shoving.
Reference
https://theconstructor.org/transportation/corrugation-shoving-flexible-pavements/30886/
Infographic: 5 Causes of Shoving & Rutting