Procedures for the Evaluation of
Sheet Membrane Waterproofing
CHARLES J. KORHONEN, JAMES S. BUSKA, EDEL R. CORTEZ, AND ALAN R. GREATOREX
provement and considered as an important bridge
INTRODUCTION
element.
At the request of the New England Transporta-
Bukovatz et al. (1983) provided a similar en-
tion Consortium (NETC), the U.S. Army Cold Re-
dorsement of waterproofing systems when they
gions Research and Engineering Laboratory
characterized the performance of sheet and liquid
(CRREL) conducted laboratory studies from
membranes as satisfactory after 12 to 16 years of
March 1998 to March 1999 to standardize proce-
field exposure. Wojakowski and Hossam (1995)
dures to evaluate bridge deck membranes. This
later reevaluated six of the eight membranes stud-
report presents the results of these studies and
ied by Bukovatz et al., concluding that the gen-
completes the requirements of NETC Project Num-
eral performance of the membranes had decreased
ber 94-3.
significantly. After 25 years of service, they esti-
mated that the lives of some systems had been ex-
Background
hausted. Frascoia (1993) projected that the mem-
branes he studied would provide protection from
Waterproofing membranes have been used to
salt contamination for more than 50 years.
protect concrete bridge decks by transportation
A membrane will protect a deck only if it is in-
agencies in New England for more than two de-
stalled properly, stays intact, and remains firmly
cades. Over the years, membranes have proved
bonded to the deck; cracked or poorly bonded
useful for preventing water and deicing salts from
membranes can lead to serious roadway deterio-
penetrating the concrete and corroding the embed-
ration such as cracking and potholing. Construc-
ded reinforcing steel. Frascoia (1983), in his 11-yr
tion is a crucial time in the life of a membrane,
field exposure study of 33 membrane systems,
because it is during construction that most prob-
demonstrated that brushed-on coatings of coal tar
lems begin. For example, membranes are subject
emulsion significantly reduced the ingress of chlo-
to abrasion damage from foot and vehicle traffic,
ride into concrete, though not as efficiently as sheet
puncture from dropped objects and rocks pressed
systems. Unprotected bridge decks absorbed 6.97
lb/yd3 (4.11 kg/m3) of chloride ions in the top inch
into the membrane, and poor adhesion due to in-
adequate workmanship, inclement weather or
of concrete, but the decks absorbed only 0.65 lb/
yd3 (0.38 kg/m3) when the concrete was coated
material defects. Poor adhesion can also result
with tar emulsion and 0.50 lb/yd3 (0.30 kg/m3)
from the deck surface being too rough or uneven.
Whatever the cause, inadequately installed mem-
when a sheet membrane was used on top of the
branes tend to puncture, blister, and crack at some
concrete. However, tar emulsions have not pro-
point during their service life, which weakens a
vided consistent protection and were judged by
membrane to chloride and moisture penetration
the Vermont Agency of Transportation as unac-
and ultimately results in failure of the overlay
ceptable. Because chloride does not seriously cor-
rode rebar until it reaches at least 1.30 lb/yd3
pavement. In turn, this accelerates deck deterio-
(0.77 kg/m3) (Lewis 1962, Clear 1974), an
ration and presents rough surfaces to the motor-
ing public.
interlayer waterproofer should thus be an im-
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