10% entrapped air? Structural concern?

[vato]

I have a very unprofessionally placed retaining wall containing horizontal cold joints and excessive honeycomb. Too many issues for one thread. I'm looking at density here. We took cores and got some decent compressive strength results, but the density is ~135 pcf. The density appears to be he result of entrapped air. Is there an ACI minimum density for normal weight concrete? And is there any guidance for reducing the compressive strength based on a low density concrete?

 

[JedClampett]

Even unprofessional contractors should of taken cylinders for compressive testing. Didn't they? If you don't have compressive results you're kind of up the creek without a paddle.

 

[vato]

We drilled out cores to get density and compressive strength. Density is 135pcf and comp strength is 3000 psi.

 

[hokie66]

I wouldn't call this low density concrete, but rather uncompacted concrete.

 

[Ron]

Agree with hokie66. Still in the density range of normal weight concrete, yet another example of how easy it is to achieve compressive strength while compromising durability with underconsolidation of the concrete. Don't let compressive strength be your only acceptance criterion. Underconsolidation to this degree will seriously compromise the long term durability of the concrete and the wall. If you are in a freeze-thaw area, long-term will become short term!

 

[bridgebuster]

You may have to re-check the stability of the wall. If the design assumes 15o pcf and sliding and overturning factors of safety were at or near bare minimum you might have a problem.

 

[msquared48]

Agree with the above too with the additional thought....

Was this a plant batched mix design?

At 135 it also sounds like a mix of lightweight and normal weight aggregate.

Mike McCann, PE, SE (WA)