Concrete strength Limitation ACI 318

[Murali27]

Hi all,

Ref: ACI 318 - 2002

Do we have any restraints in design methodology for using higher strength concrete 15 ksi ?

Thanks in advance

 

[UcfSE]

Yep, and it varies depending on exactly what kind of strength you are calculating. I don't work with concrete with that much compressive strength so I can't tell you what and where they are. Shear strength I believe has one, and strut and tie is one.

 

[rapt]

Murali27,

Above about 7ksi the concrete stress strain curve strats to vary significantly from the assumed curve in the rectangular stress block. The constants for this must be modified. This is covered in the Canadian code.

Also, creep and shrinkage are very different. There is much more chemical shrinkage and less drying shrinkage.

The concrete is much less ductile and for compression members the ties are much more important.