Concrete Brain teaser question

[SKJ25POL]

Does the pour direction of concrete affect the strength of concrete
If two concrete elements one poured vertically and the other poured horizontally will one be more stronger?

 

[r13]

Q1 - No. But tt may affect location and direction of the cold joints, which in turn might affect the performance of the structure.
Q2 - I don't understand the question.

 

[JoelTXCive]

1) I don't understand the question either

2) If you really want to get into the weeds, then I would argue a 12" thick horizontal slab element would have more flexural/shear capacity than a similarly reinforced 12" thick wall subject to out of plane loading. My reasoning would be that the wall steel doesn't develop as fast because it has so much concrete under it. (I'm thinking of the 1.3 penalty in development lengths here)

 

[jayrod12]

Would the 1.3 penalty apply to out of plane bending for walls? I didn't think so. For in plane bending, sure, but out of plane there's not significant concrete below the tension steel.

Also, while the grammar police is in full force today, "more stronger" isn't a thing. Stronger would be the correct term, or "possess more strength". But I digress.

Subjected to the same loads, same reinforcing etc, no I don't expect that whether it's cast horizontally or vertically to make a difference.

 

[Settingsun]

The question is eg insitu vs tilt-up (that wording is for the grammar police). Lap lengths might be affected due to bars being top bars in one vs vertical in the other. I don't think there's any design benefit/ penalty otherwise. Maybe a measurable difference in reality due to water-gain concrete across full section in one case vs just one edge of the section in the other case (but full length of member).

 

[RabitPete]

Typically concrete is easier to consolidate in thin layers, so horizontal pour would be preferred to vertical one.

 

[jayrod12]

But placement things aside, which I agree with. All else being the same, strength of concrete, reinforcing sizes and layout, applied loads (both axial and out-of-plane), there should be no difference in their capacities.

 

[Ron247]

Design strength or actual strength? Design strength would be addressed in the code for any given condition the code addresses. Actual strength could be anything. The concrete poured on saturday may be stronger than the same type of pour on Monday. That is the nature of concrete. Just like 3 test cylinders from the same batch and project do not break at exactly the same value. So, no real way to know.