Enlist the causes of failure of rigid pavement

The following are the several forms of distress that cause stiff pavement failures:

 Joint Spalling, Faulting, Polished Aggregate, Shrinkage Cracking, Pumping, Punch out, Linear Cracking, Durability Cracking, and Corner Break

Joint Spalling

Excessive compressive stress causes joint deterioration, which is commonly referred to as spalling. This could be linked to reactive aggregate-induced joint infiltration or pavement expansion. Joint spalling can also be caused by poor concrete or construction techniques. The back of the slab and down to the joints show little edges to enormous spalls.

The following are the main reasons for joint spalling in stiff pavements:

• Excessive load on joints caused by increased traffic or infiltration of any incompressible materials
• The joints that are made of shaky concrete
• Water has accumulated in the joints, causing rapid freezing and thawing.
• Rigid Pavement Joint Spalling

Spalls in the joints can be avoided by utilizing proper building procedures or sealing the joints.

Faulting

• Faulting refers to the difference in elevation between the joints.
• Pavement settlement because of a sagging foundation
• Pumping or erosion of material beneath the pavement slab, resulting in cavities beneath the slab and causing settlement.

Polished Aggregate

This distress is caused by the repetitive application of traffic. These are inflexible pavement failures that occur when the aggregates above the cement paste in the case of PCC are extremely small, the particles are not rough, or the aggregates are angular in shape, and the vehicle skid resistance is insufficient. Prior to starting the building, the polishing degree should be selected.

Shrinkage Cracking

These are hairline cracks with a length of less than 2m. They don’t extend all the way to the edge of the slab. The settling and curing of the concrete slab cause cracks. Increased water evaporation owing to temperature cracks causes these. Shrinkage fractures in inflexible pavements could also be caused by improper curing.

Pumping Effects

Active vehicle loads crossing the pavement on a frequent basis produce this irritation. As a result, the sub-fine base’s materials will flow with the water and be evacuated along with it. Evacuation produces greater voids beneath the pavement with each subsequent evacuation. The technique through which this form of rigid pavement collapse is indicated is by stains on the pavement or on the shoulder surface.

By preventing water from collecting at the pavement’s sub-base contact, pumping can be avoided. This can be accomplished by keeping the deflection to a minimum and providing a sturdy, well-built sub-base. To prevent the subgrade beneath it from being saturated, the constructed sub-base must have enough drainage. The greatest answer for pumping distress is to install an underground drainage system in modern pavement design.

Corner Breaks

When the underlying structure is eliminated and there is no longer any support below to carry the vehicle load, corner fractures emerge. Either a full slab replacement or a repair to the whole depth is required.

Punch-out

Punch-out distress is a term used to describe a fractured concrete slab in a specific place. Distress can manifest itself in a variety of ways. Joints and cracks are the most prominent features. The breadth of the joints and cracks will mostly remain at 1.5 meters. Heavy repetitive loads, slab thickness insufficiency, foundation support loss, or design flaws such as honeycombing are the most common causes of punchouts.

Linear Cracking

In stiff pavements, these types of failures split the slab into two or three pieces. Traffic loads at many levels, curling owing to heat gradient, and moisture loading at multiple levels are all factors that contribute to such failures.

Durability Cracking

The freezing and thawing cycle will cause frequent expansion and contraction, causing the concrete to gradually break down. Patterns of cracks on the concrete surface as layers that are parallel and closer to the joints characterize this sort of distress. The portions of the concrete that appear to be more saturated are the joints and fissures. The ‘D’ cracks are dark deposits that can be found here. This inflexible pavement degradation will eventually lead to the slab’s ultimate disintegration.