zebraso said:
It is interesting. The stampcrete fractures look pretty good. I hate to call that "curious", but.....
IanCA said:
According to the Moribato report Link page S2A-1.1 the parking deck had no waterproofing.
I think the way the stampcrete has come up in sheets demonstrates how it was not bonded to structural deck below and trapping moisture between stampcrete and non waterproofed structural deck. I also feel the way some of the stampcrete is shifted at columns and the major concrete failure cracks in parking deck area near south wall and patio deck junctions, definitely point to the parking deck failure being due to chemical reactions in that area could be a huge factor in that area being initial failure point, near south wall. Couple that with construction vibrations next door, and cyclic loading of parking deck from auto movements and that area is a very stressed area.
I will be first to admit, my chemistry education ended as freshmeat in College, and had long been forgotten except for times where it affects everyday life like the voltaic cell battery in my autos. I remember as a kid my dad storing a 12V auto battery on a concrete pad outside our home and how it ate the paste in the concrete at a rapid rate and left honeycomb of aggregate and voids showing. From that time on, dad burned in my brain to put a wood board under auto battery to protect concrete. He was mechanical engineer so not chemistry major. Concrete patio was under a cover so not a lot of rain getting to it, but perhaps some in blowing rains.
Interesting short read on "Case Studies Show Galvanic CP Effective on Corroded Reinforced Concrete Structures". Interesting to note that repaired areas create a potential difference between old and new areas and basically cause the cancer to spread to new areas around repaired area. Here is quote below form short article:
"Chloride-induced corrosion of reinforcing steel in concrete is a major problem worldwide. Chlorides can be introduced into concrete through deicing chemicals, seawater, soil, or as contaminants in the concrete mix. This can lead to pitting corrosion and concrete deterioration."
"Localized repairs are often performed to address concrete corrosion damage. When a repair is completed, new corrosion sites can form just outside the repaired area and are driven by the residual chloride contamination and the difference in potential between the steel in the chloride- contaminated and chloride-free sections. When incipient anodes form, further repairs will be required. The patch repair process may be repeated several times over the remaining life of the structure."
