# Spalling

Cracking, breaking or chipping of joint/crack edges. Usually occurs within about 0.6 m (2 ft.) of joint/crack edge.

- Canonical URL: https://pavementinteractive.org/reference-desk/pavement-management/pavement-distresses/spalling/
- Last updated: 2018-09-19
- Review: reviewed by licensed professional engineers on the previous Pavement Interactive site, where reviewers were not recorded by name

## Description

Cracking, breaking or chipping of joint/crack edges. Usually occurs within about 0.6 m (2 ft.) of joint/crack edge.

![Spalling along a linear (panel) crack.](https://pavementinteractive.org/wp-content/uploads/2011/10/200px-Cracks_in_pavement.jpg)

![Onset of spalling up close.](https://pavementinteractive.org/wp-content/uploads/2011/10/200px-Spalling.jpg)

![Bad construction joint spalling.](https://pavementinteractive.org/wp-content/uploads/2011/10/200px-Bad_spalling1.jpg)

*Figures 1–3.* Spalling along a linear (panel) crack. Onset of spalling up close. Bad construction joint spalling.

## Problem

Loose debris on the pavement, roughness, generally an indicator of advanced joint/crack deterioration

## Possible Causes

Possible causes are (AASHTO, 1993[^1]):

- Excessive stresses at the joint/crack caused by infiltration of incompressible materials and subsequent expansion (can also cause blowups).
- Disintegration of the PCC from freeze-thaw action or "D" cracking.
- Weak PCC at a joint caused by inadequate consolidation during construction. This can sometimes occur at a [construction joint](https://pavementinteractive.org/glossary/construction-joint/) if (1) low quality PCC is used to fill in the last bit of slab volume or (2) dowels are improperly inserted.
- Misalignment or corroded dowel.
- Heavy traffic loading.

## Repair

Spalling less than 75 mm (3 inches) from the crack face can generally be repaired with a [partial-depth patch](https://pavementinteractive.org/reference-desk/materials/portland-cement/portland-cement-strength/pcc-patching/). Spalling greater than about 75 mm (3 inches) from the crack face may indicated possible spalling at the joint bottom and should be repaired with a [full-depth patch](https://pavementinteractive.org/reference-desk/materials/portland-cement/portland-cement-strength/pcc-patching/).

## Sources

[^1]: AASHTO (1993). AASHTO Guide for Design of Pavement Structures. American Association of State Highway and Transportation Officials. Washington, D.C.