Carton form foundation void moisture problems

[ContractorGPC]

Does anybody have any information related to correcting moisture issues in the void space left after the carton form deteriorates.
Moisture coming through slab and causing mastic bleading. Very high PH levels. There is a moisture barrier. Highly expansive soils.
Thanks Rick

 

[hokie66]

What is "mastic bleading"? High pH is good, concrete is alkaline and needs to remain so. A bit more description about the slab would help, and where the moisture is appearing.

 

[Ron]

Mastic bleeding, high pH and moisture are interrelated.

Moisture is likely inherent moisture in the concrete, condensing at or near the surface from changes in temperature/humidity environment. High pH and moisture will prevent mastic (assumed water based mastic) from properly curing. It will re-emulsify when exposed to high pH and moisture. High pH can also cause chemical changes in water based mastics (alkali burn).

I'm not sure what a carton form is...please give us a bit more information on this and the concrete, such as water-cement ratio, slump, etc.

 

[JAE]

A carton form, from previous projects in south Texas, involved simply a cardboard carton system created in tube-box form to be placed beneath concrete slabs or beams to create a permanent void under the concrete. This was used to prevent expansive clays from swelling up under the concrete and lifting up the concrete structure.

The cardboard was usually treated with a wax or something to keep it stable for a time, enough time to place the concrete without the moisture turning the cardboard to mush. After the concrete had hardened the cardboard would eventually deteriorate away, leaving a void.

Usually these systems would require a fill retainer on the edge of the slab, or along the beam, wherever the void ended, to keep the adjacent fill from eroding into the void.

I'm not sure I understand the original post question - carton forms are not used for waterproofing or water repelling agents.