About 6 months ago I have poured concrete in a plastic mould. The mould was plastic plinth for sun umbrella. It is usually filled with water but it cracked so I filled it with concrete. Before pouring I glued the cracks with generic cyanoacrylate glue.. I prepared concrete mix with coarse and fine sand, cement and PP fibers. I was aiming for 0.3 water to cement ratio. I added a superplasticizer based on 2-octyl-2H-isothiasol-3-on. The plasticizer was dark purple fluid with distinct smell.I used quite a lot of it, somewhere near the max of recommended dose. The concrete stayed soft for quite a while and I thought it would not harden at all. After a week it became warm and solidified. The surface at the opening where I poured it in (the top) was soft to the touch for a few weeks. You could scratch it with a fingernail. But now is rock hard. What I have noticed after a few weeks was dark purple excretion under the glued cracks. And I think it even softened the glue. It looked purple like plasticizer, smelled like plasticizer and had a stingy taste. The concrete itself is of normal color. Now, even after a few months a purple excretion leaches out of cracks in plastic. Is this really plasticizer leaching out? Is this normal?
Things to consider:
Final w/c somewhere around 0.3.
Max recommended dosage of plasticer.
On top of the mold is an empty cavity which I left filled with water to keep the concrete moist during curing. The surface of concrete underneath is hard.