Clean Your AFGB1’s Compaction Chamber

“I’m told I need to keep the compaction chamber of my AFGB1 free of asphalt.  It’s a real pain digging the asphalt out of the bottom of the chamber.  Is it really such a big deal?”

Yes, keeping the bottom of your AFGB1 compaction chamber free of asphalt is important.  Frequently, our field service technicians find the bottom of the compaction chamber of AFGB1 gyratory compactors filled with hardened asphalt.  A buildup of asphalt debris in the bottom of your machine can cause damage that can be costly to repair.

The System

Three mold clamps are positioned symmetrically around the base of the compaction chamber.  The location of two of the clamps are identified in Figure 1.  The third clamp is located on the back side of the chamber.  Figure 2 provides a view inside the compaction chamber with 2 of the 3 mold clamps visible.

Figure 1:  Mold Clamps.
Figure 2:  Mold Clamps Inside the Compaction Chamber.

The clamps engage the mold in pockets near the base of the mold when pressure reaches 600 kPa to hold it in place during compaction of a specimen (Figure 3). 

Figure 3:  Mold and Mold Pocket.

The Problem

A buildup of debris in the base of the compaction chamber can cause several problems. 

  • Debris may prevent a clamp from engaging the mold, which means the mold may not be properly held in place during compaction of a specimen.  This may place added stress on the other clamps and damage them. 
  • It could damage the clamps requiring replacement.  Debris can chip and bend the clamps making the unable to perform their function.
  • It could damage the cylinders that drive each clamp causing them to leak and requiring their replacement.

 What does Pine recommend?

  1. The solution to this problem is simple.  Remove asphalt and aggregate from the base of the compaction chamber after each specimen.  Loosen it with a screw driver or some similar tool.  Then, suck it out with a vacuum.  A small shop vac works great for this purpose.
  2. If you’ve allowed asphalt to accumulate in your machine, it will require some additional effort to loosen the hardened asphalt and remove it.  “Purple Power” degreaser, found in most hardware stores, works well to break down hardened asphalt cement.
  3. Diligently cleaning the compaction chamber after each specimen will maximize the performance of your machine, provide the most consistent results, and help you avoid repairs.

Want to learn more?

Watch Pine’s video on how to properly lubricate your AFGB1 gyratory compactor.

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