(continued) Mud Mat (Mud Slab)

[GGGGeo]

thread256-377062
This was a very interesting subject. Please correct me if I am wrong, if the soil report said allowable soil bearing is 1,500 psf (assuming it is the maximum allowable value. unclear that if any special foundation preparations are needed) for footing founded between 0-10 feet deep and structural demand is indeed less than 1,500 psf, then the "mud slab" may not be such a bad approach. The footings will gain the bearing support as recommended by the soil report and the mud slab will also serve as a working table over the "soft" soils.

However, if the pressure from structure needs more than 1,500 psf, the footing needs to be sized up accordingly, but the mud slab in this case shall not be considered to provide structural value.

 

[BigH]

A mud mat or blinding concrete, being in the order of 50 mm thick or so, is NOT a structural element and should not be considered as such. it is there to prevent the approved soil foundation from being disturbed due to precipitation or workers walking on it and disturbing it (normally with some water issues) and to provide a level surface on which to sit the chairs for your slab/footing steel.

That's my opinion on "Let's get real!"

 

[Okiryu]

We also normally use 50 mm mud mats, with f'c=18 MPa. Mud mats also allow for putting markings for clean measurements.