Companion concrete block specimens were also subjected to four cycles
of simulated sea water wetting and drying in a laboratory accelerated
exposure cabinet. A summary of recent readings of corrosion rates of original
specimens still at Treat Island is given in the Data Table.
New Program
In 2000 a series of 162 specimens were prepared and installed near high
tide level on the beach at Treat Island, the dimensions of concrete specimens
(55 x 230 x 300 mm), are similar to those used in a previous study (Erdogdu
1992, Kondratova 1999), which will enable comparison with the results
of those previous studies. Using these specimens it should be possible
to get results in a short period of time, due to the small cover depth
used.
Cement containing 8.7% low alkali silica fume (LASF) and a maximum aggregate
size of 12 mm was used in the fabrication of all the specimens. Furthermore,
three different amounts of fly ash will be tested on the basis of partial
replacement of cement by volume. The mix proportions for these new specimens
is given in the Data Tables.
Since 1991, approximately 200 2 by 9 by 12 in. concrete specimens containing both epoxy coated and uncoated 15 mm diameter steel reinforcing bars with 20 and 30 mm concrete covers have been installed at Treat Island to conduct comparative corrosion durability studies. Characteristics parameters for the concrete specimens are 0.25 water-to-cement ratios, 0.4 mm cracks oriented transverse to the axis of the steel reinforcing bars simulated in half of the concrete block specimens, and several types of epoxy coatings and three types of commercial corrosion inhibitors for corrosion protection evaluations.