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NEW SOUTH WALES ROADS & TRAFFIC AUTHORITY (RTA)
& VICROADS Geopave (Victoria)
Hydrophobic Pore-blocking Ingredients (HPI's) -"Caltite" & "3CC"
vs.
"Crystal-growth" Additive, Silica fume, GGBF Slag & Fly Ash
Though the latter half of the 1990's, two Australian State Governments (NSW Roads & Traffic Authority (RTA),
and VicRoads Geopave in Victoria), conducted extensive research into extending the durability of bridge structures
through "waterproofing" of concrete.
This allowed a direct comparison of the performance of Cementaid's "Caltite" and "3CC" system
concretes against densifiers such as pozzolans (silica fume, slag, PFA, etc.) and a "crystal-growth"
type additive.
NSW Roads & Traffic Authority (RTA) (Australia)
CTI Consultants Pty. Ltd.
The NSW RTA commissioned a long-term testing & research program to compare the performance of a number of waterproofing
materials, including various coatings, in high quality 50 MPa concrete.
Data for Water Up-take and Chloride Penetration after cyclic salt water immersion are summarised
here for the "Caltite", "3CC" and the "crystal-growth" concretes; |
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Reduction in Water Uptake
Relative to "Control"
Everdure Caltite 92.4%
3CC 91.5%
"crystal-growth" 12.5%
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Observations:
"..the HPI's ("Caltite" and "3CC") exhibit a characteristic pattern similar to silanes,
with the concrete losing more weight during each drying stage than was absorbed in the previous immersion phase,
and with a continual overall weight reduction leading to drier concrete."
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Reduction in Chloride Penetration
(20 mm depth)
Salt Water Immersion & Drying Cycles
Everdure Caltite 100%
3CC 98.4%
"crystal-growth" 25.3%
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Report Conclusion;
"The pore-blocking hydrophobic additives (Caltite and 3CC) performed very well, especially at the deeper intervals
where chloride reductions in excess of 97% were recorded.Based on these results, hydrophobic pore-blocking additives,
can be used to protect concrete against moisture and chloride ingress under condition of atmospheric exposure." |
VicRoads Geopave (Victoria, Australia)
For waterproofing & durability of their structures, VicRoads measured and compared the reduction in the Volume
of Permeable Voids (VPV) (ASTM C642) provided by "Caltite" as well as densifying additives such as
silica fume, blast furnace slag, PFA, and a "crystal-growth" type additive.
Concrete samples are dried to constant weight before 48 hours water immersion, followed by 5 hours boiling to ensure
maximum possible water penetration before re-weighing in water and in air to determine the total Volume of Permeable
Voids. Average results as follows; |
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%REDUCTION IN
Vol. of Permeable Voids
CALTITE 30%
Silica fume 20%
PFA 15%
ggbf Slag 10%
crystal-growth 5%
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Recommendations ("Caltite"):
"The Hydrophobic Pore-blocking admixture (Everdure Caltite) has been found to outperform both conventional
and SCMs concrete (fly ash, slag, silica fume) with far greater reductions in VPV.
This is a very efficient material in terms of reductions to VPV |
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