Common Causes
Both problems are primarily caused by the way concrete is placed and compacted.

• Vibration may not be adequate or well spaced.
• The mix may be sticky.
• Entrapped air not removed by vibration, air bubbles move to the form surface.
• Improper application of Form Release agent or wrong type

Prevention
Avoiding Bug Holes
• Work the voids at the form face up and out of each lift.
• Let the vibrator drop through the lift, then vibrate upward.
• Don't overvibrate at the center of the wall.
• Move the vibrator as close to the form as possible.
• Add upward external vibration if necessary.
• Reduce the height of each lift to make void removal easier.
• Consult ready mix producer and review aggregate size and shape options.
• Reduce sand content.
• Use low slump concrete.

Avoiding Honeycombing
• Do not place concrete over 4" slump-for a higher slump, use a high range water reducer admixture.
• Improve compaction during concrete placement.
• Deposit concrete as uniformly and vertically as possible. A Tremie may be required to reduce free fall.
• Decrease the lift height for more efficient vibration.
• Insert the vibrator more frequently.
• Vibrate as close to the form face as possible.
• Be sure to vibrate through each lift.
• Minimize delays between lifts.
• Use a super-plasticized concrete if the reinforcing or the section's design restricts vibration.
• Adjust the concrete mix proportions by decreasing coarse aggregate and increase sand content.
• Consider air-entrained concrete.
• Check the tightness of joints in the forms. Be sure to secure all form joints.
• Look for grout leakage through openings in the formwork.