EXPAND-Tite Controlled Expansion Waterstop Sealant Compression Joint Pressure Test

PURPOSE OF TEST
This test was performed to demonstrate the pressure-holding capabilities of a compression joint, assembled with EXPAND-Tite Controlled Expansion Waterstop over extended periods of time, under increasing hydrostatic pressures.

TEST PROCEDURE
Two 14” diameter by 3” thick disk-shaped concrete specimens were used for the test. Each was cast with a continuous, mating, tongue or groove joint around its circumference.

The top (or tongue) specimen also contained a cast-in 2” diameter center cavity for holding water. Standard plumbing fittings were cast into the center cavity and thoroughly sealed to withstand the anticipated pressures. These fittings were later used to introduce water and air into the cavity as a test of sealant’s ability to maintain hydrostatic pressure during the procedure.

Component Assembly Prior to assembly, the surfaces of the tongue and groove areas were primed completely with a recommended priming material. A continuous strip of (3/4” x 1”) EXPAND-Tite Waterstop was pressed firmly into the groove of the lower disk with the two ends of the sealant overlapped to form an uninterrupted seal.

Four 1/8” (or _”) thick steel spacers were placed equidistant around the outside edge of the grooved test specimen to maintain a consistent gap between the two specimens during assembly.

Four threaded steel rods and clamping brackets were put into place around the outside of the disks and tightened to hold the two specimens at the 1/8” (or _”) distance from one another for the duration of the test period.

Once an even gap was achieved around the entire perimeter of the test assembly, the rods were loosened just enough to remove the spacers completely. Note: This test was performed twice…
- Once with a 1/8” gap between the specimens
- Once with a _” gap between the specimens

Pressurization
Hydrostatic pressure was initially applied by filling the center cavity with water and allowing the concrete to become saturated for 72 hours at a pressure of 5lbs. per square inch. The hydrostatic pressure (as indicated below) was controlled via regulated, compressed air and maintained for the specified number of hours (as shown in the tables).

With 1/8” gap:
PSI HOURS
5# 72 (3 days)
10# 48 (2 additional days)
15# 888 (37 additional days)
20# 1,004 (41 additional days)
25# 1,000 (41 additional days)
30# 16,000 (666 additional days)

With _” gap:
PSI HOURS
5# 72 (3 days)
10# 48 (2 additional days)
15# 864 (36 additional days)
20# 1,008 (42 additional days)
25# 1,000 (41 additional days)
30# 600 (25 additional days)

TEST RESULTS
After full pressurization for the number of hours shown above, EXPAND-Tite Controlled Expansion Waterstop Sealant showed no deterioration. In all cases, the full integrity of the seal was maintained throughout the test period without leaks. In addition, the controlled expansion of the sealant prevented the formation of fractures or similar failures which are not uncommon with sealants that expand excessively, placing undue pressure on structural components.