Chapter 5: Chip Seals

Troubleshooting

This section provides information to assist maintenance personnel in troubleshooting problems with chip seals. The guide, along with a related table on problems and solutions, address common problems encountered during the course of chip seal projects.

Troubleshooting Guide

The troubleshooting guide presented in Table 7 associates common problems with their potential causes. One of the most common problems is flushing.

In addition to the troubleshooting guide, Table 8 lists some commonly encountered problems and some recommended solutions.

Table 7: Troubleshooting Chip Seal Problems (Hot/Emulsion/Asphalt Rubber)
Cause	Excessive Loss of Aggregate	Crushing of Aggregates	Pickup of Binder	Adhesion Problems	Raveling of Aggregates	Streaking of Binder	Transverse Patches	Flushing	Failure in Shade	Polishing of Aggregate	Poor Mosaic of Finished Mat
Cause	Problem
Poor Traffic Control	•		•		•				•		•
Poor Equipment	•		•		•		•	•	•		•
Spray Temperature	•		•		•	•	•		•		•
Vehicle Speeds	•				•	•	•	•	•		•
Distributor Nozzles	•				•	•		•	•
Climatic Conditions
Cold Surfaces	•			•	•				•		•
Wet	•			•	•				•		•
Windy	•			•	•				•		•
Binder
Wrong Binder	•		•	•	•	•		•	•		•
Too Little Binder	•			•	•				•		•
Too Much Binder	•		•					•			•
Aggregate
Too Little	•		•					•			•
Too Much	•	•		•	•		•		•		•
Wet	•			•	•			•	•		•
Dirty	•			•	•				•		•
Quality	•	•		•	•				•	•
Wrong Size	•				•			•	•	•	•
Precoat
Too Little	•			•	•				•
Too Heavy	•				•

Table 8: Common Problems and Related Solutions
Problem	Solution
Streaking or drill marks in the emulsion	Ensure emulsion is at correct application temperature. Ensure the viscosity of the emulsion is not too high. Ensure all the nozzles are at the same angle. Ensure the spray bar is not too high or too low. Ensure the spray bar pressure is not too high or too low. Ensure nozzles are not plugged.
Exposed emulsion after chip application	Ensure the chip spreader gate is not clogged or malfunctioning. Ensure the chip spreader is covering all the binder
Excessive chips/Many chips with small amounts of emulsion	Ensure the chip spreader gate is not malfunctioning or chipper head is not overloaded. Lower the chip application rate.
Uneven chip application	Re-calibrate the chip spreader; ensure all spreader gates are set the same.
Emulsion on the top of chips	Ensure the chip spreader is not operating too fast. Ensure trucks, rollers, and pilot cars are operating correctly at low speeds.
Chips being dislodged	Ensure the emulsion application is not too light. Ensure the chips are not dirty or dusty. Ensure the traffic or equipment speeds are not too high. Ensure brooming does not occur before the emulsion is properly set.
Emulsion bleeding or flushing	Ensure the emulsion application is not too high. Ensure the aggregate application is not too low.
After brooming, loss of chip at centerlines	Check centerline procedure. Check binder application rate.
Excessive splattering of the emulsion	Lower the spray pressure.