CONCLUSIONS
•Sulfate released into
solution shows that specimens with bacteria did not cause significantly more concrete corrosion.
•Calcium production
shows that specimens without bacteria released the most concrete into solution.
–Evidence of live
bacteria (contamination).
–Precipitates on
concrete surface.
–Gypsum and ettringite
both contain calcium and sulfate ions.
•Higher temperature (35
C) increased corrosion.
–Both with and without
bacteria.
•pH effect not
significant.
–pH was not
significantly different despite daily adjustment to pH 4 vs. 8
•The true sulfur
concentration in the liquid was not represented by the mass of sulfur added, due to preference to float and
stick to beaker.
–This affected the
sulfate production, which in turn affected the rate of concrete corrosion.
–The specimen with the
most sulfate and calcium production was 1 g/L [S].