Sawn joints spalling

[hoopvols]

What are your ideas and experiences on why the edges of saw cut contraction in a slab on grade are spalling off. My thought is the joints were cut too soon. The rest of the slab looks good but almost all the joints look like the attached picture.

 

[Ron]

Joints look like they were done with a Sofcut saw. Too narrow for typical blade. Surface is also burnished with hard trowel. This can create a very brittle surface that is then flaky when cut. Agree that the joints were cut early, but not really too soon.

 

[msucog]

looks like it was cut too early and too aggressively

 

[msquared48]

And what's with the boot print?

Mike McCann
MMC Engineering
Motto: KISS
Motivation: Don't ask

 

[GeoPaveTraffic]

I agree looks like the joint was cut to soon for the combination of saw, strength, and agregate.

I will admit however, that I have only seen streets cut with a softcut saw. Never seen a slab on grade cut that way, so I cant comment on the effect of burnished finish.