Asphalt Paving 3

[pantro1977]

We finished laying asphalt (BM 25.0) on Saturday. During the operation everything was done and tested according to VDOT (Roller pattern, control strip, etc). We took core samples the same day and they were test by noon of the following day. I just got the results of the density test performed on the samples and non of the samples met the required 95% density. What options do we have to correct this problem?

 

[Ron]

If it is a state project, the usual procedure is to reduce the pay to the contractor based on a sliding scale of density.

If the density is significantly off, you might require the contractor to mill and overlay.

How low was the density? Was the density in the field compared to lab density or a control strip density? What size cores were used? Do you know if the testing was performed properly?

What do you think caused the low density? Was it placed too cold? Was the equipment too light or did break-down rolling not occur quickly enough? Was the mix design "off". Is this a "SuperPave" mix?

 

[Zambo]

Ron is right, there is a reason for the low densities and it will help to know why. Any weather problems? or the layer thickness low? If no obvious reason I would wonder about the testing and consider testing again.

 

[conceng]

Coring pavements the same day they are paved typically requires special cooling measures at the core location such as ice to firm up the pavement enough to not cause damage during coring or core removal. Without cooling there is a high potential for deformation of the core, leading to lower density determinations. Waiting until the next day to measure them can also lead to deformation if the cores are not stored properly or are not kept cool enough.

Greg

 

[conceng]

Coring pavements the same day they are paved typically requires special cooling measures at the core location such as ice to firm up the pavement enough to not cause damage during coring or core removal. Without cooling there is a high potential for deformation of the core, leading to lower density determinations. Waiting until the next day to measure them can also lead to additional deformation if the cores are not stored properly or are not kept cool enough.

Greg