"The added material is typically 3%. The rebar is mainly to overcome Building code standards imposed rather than a major need. "
- I meant adding rebar would afford an additional strengthening component, so it would allow for the use of less overall material, (binder and fill), because skinnier geopolymer beams would be as strong as fatter regular concrete beams. Not important.
"Have you ever cement rendered an old brick wall? "
- Yes. It always fails at the point between two dissimilar materials. It also always fails at the point between two dissimilar cure times of the same materials. It also fails at the point of two dissimilar mixtures, even if they are curing at the same time. Its very tricky stuff, and when we're talking about walls as old as these, I'm going to expect we'd see many examples of all these kinds of failures revealing some tell tale substructures, but I don't. I do see some odd circumstances of a surface vitrification chipping off, or a rock that appears to have already lost its surface, but nothing that shows these kinds of issues. And concrete people would spot that as well as machinists like Chris Dunn can describe tool marks. I don't know. There's some challenging issues still.
And when I hit a stumbling block like this, it cascades in my mind and I start considering the Unfinished Obelisk surrounding scoop marks, or really any curious seeming modeled appearance in the actual bedrock. And I fly back to my pet place holder.
Its tricky, this one. But its fun as hell. Feels like cutting edge discussions. lol.
Edited 2 time(s). Last edit at 08-Jan-20 23:24 by Open mind.