Publisher’s version / Version de l'éditeur:
Construction Specifier, 45, Dec. 12, pp. 97-105, 1992-12-01
READ THESE TERMS AND CONDITIONS CAREFULLY BEFORE USING THIS WEBSITE. https://nrc-publications.canada.ca/eng/copyright
Vous avez des questions? Nous pouvons vous aider. Pour communiquer directement avec un auteur, consultez la première page de la revue dans laquelle son article a été publié afin de trouver ses coordonnées. Si vous n’arrivez pas à les repérer, communiquez avec nous à PublicationsArchive-ArchivesPublications@nrc-cnrc.gc.ca.
Questions? Contact the NRC Publications Archive team at
PublicationsArchive-ArchivesPublications@nrc-cnrc.gc.ca. If you wish to email the authors directly, please see the first page of the publication for their contact information.
NRC Publications Archive
Archives des publications du CNRC
This publication could be one of several versions: author’s original, accepted manuscript or the publisher’s version. / La version de cette publication peut être l’une des suivantes : la version prépublication de l’auteur, la version acceptée du manuscrit ou la version de l’éditeur.
Access and use of this website and the material on it are subject to the Terms and Conditions set forth at
Waterproofing with elastomeric membranes
Mailvaganam, N. P.; Collins, P.
https://publications-cnrc.canada.ca/fra/droits
L’accès à ce site Web et l’utilisation de son contenu sont assujettis aux conditions présentées dans le site LISEZ CES CONDITIONS ATTENTIVEMENT AVANT D’UTILISER CE SITE WEB.
NRC Publications Record / Notice d'Archives des publications de CNRC:
https://nrc-publications.canada.ca/eng/view/object/?id=0a8813a0-436c-47cf-bf3d-723a65ec12fd
https://publications-cnrc.canada.ca/fra/voir/objet/?id=0a8813a0-436c-47cf-bf3d-723a65ec12fd
Wa t e rproofing w it h e la st om e ric m e m bra ne s
N R C C - 3 4 0 6 7
M a i l v a g a n a m , N . P . ; C o l l i n s , P .
D e c e m b e r 1 9 9 2
A version of this document is published in / Une version de ce document se trouve dans:
Construction Specifier, 45, (12), Dec., pp. 97-105, December-01-92
http://www.nrc-cnrc.gc.ca/irc
The material in this document is covered by the provisions of the Copyright Act, by Canadian laws, policies, regulations and international agreements. Such provisions serve to identify the information source and, in specific instances, to prohibit reproduction of materials without written permission. For more information visit http://laws.justice.gc.ca/en/showtdm/cs/C-42
Les renseignements dans ce document sont protégés par la Loi sur le droit d'auteur, par les lois, les politiques et les règlements du Canada et des accords internationaux. Ces dispositions permettent d'identifier la source de l'information et, dans certains cas, d'interdire la copie de documents sans permission écrite. Pour obtenir de plus amples renseignements : http://lois.justice.gc.ca/fr/showtdm/cs/C-42
by
Noel
P.
Mailvaganam and Peter
G.
Collins
Waterproe»'fing
""ith
ｅｬ｡ｳｴｯｾｲｮ･ｲｩ｣＠
Nlei'Dbranes
Acquaint yourself
with elastomeric
membranes' critical
properties before
selecting one to
protect parking
decks.
D u r i n g the winter, many tons of deicing salts are spread on roaqs. These salts produce large quantities of concentrated chloride solution, which cars bring into parking garages. Some of this solution percolates through the concrete deck, entering fine cracks in the surface and promoting corrosion of reinforcing steel. Waterproofing membranes applied to decks can help prevent moisture and salt ingress and subsequent rebar corrosion.
Elastomeric waterproofing membranes in temperate climates are "subject to
rigorous temperature extremes, exposure to damaging chemicals, and high wear. A
membrane's ability to withstand these harsh conditions depends on critical character-istics tied to the physical and chemical properties inherent in the polymer resin from which the membrane is made. Properties such as abrasion resistance are provided by layered, composite membrane systems.
ｆＢｾｧｾｾｲ･＠ A. Schematic of a typical membrane system
Tie Coat
Wearing Course
Waterproofing
Membrane
Primer or
Sealer
Concrete
Deck
Critical PropertiesMost of the waterproofing systems used in parking garage decks are cold liquid-applied self-adhering elastomers. These systems are usually applied in relatively thin coats, bonded continuously to. the substrate, and cured to fonn a seamless elastomeric waterproof barrier. Typically, the systems consist of a primer, followed by a cold liquid-applied membrane 0. 75 to 1.50 mm (30 to 60 mils) thick. The primer is coated with an
abrasion-resis-tant, 60-mil wear coat. Figure A shows a
cross section of the various coats of a typical thin adhesive membrane system. Membrane systems vary in chemical com-position, type of top coat, and applica-tion method, and indi\idual properties of membranes are governed by the many factors peculiar to each material. Mem-brane types include one-component
ure-thanes, two-component ureure-thanes,
M'O-component soh·ent-borne
epoxy-ure-98 Th e ConstJ"uc:ti o n Specifier I D e f..· e•nher 1 9 9 2
thane blends, one-component water-borne. neoprenes, and rubberized asphalt mastics.
To protect concrete effectively, a wa-terproofing membrane and wearing sur-face must have f'h-e critical properties. It must be able to
• recover from elongation
• retain flexibility at low temperatures • adhere to concrete
• bridge cracks
• remain stable \\ith freeze/thaw cy-cling.
Recovery from elongation is the abil-ity of a membrane to return to its origi-nal dimensions after it has been sub-jected to continuous load and de-fonnation. Tests require a minimum of 85 percent reco\'el)· after loading to dem-onstrate the stress-relaxation capacity of the polymeric matrix.
Testing is done on free film specimens with benchmarks . The sample is stretched
.,;
"
0 c:"
!
"
.c: 0:
0 C'"
ｾ＠ ｾ＠"
"
5..
"
"
t:"
8..
g 0 .c:"
"C c:"
.; 3! .0 J! .; ! ｾ＠"'
ｾ＠to 100 percent elongation (based on the benchmarks) and held for one hour. The load is then removed and the specimen allowed to relax. After 15 minutes, the distance between benchmarks is mea-sured.
Some of the membrane types listed
above do not pass this test (see
Table
1).Those that fail may be unable to retain
their integrity with low-temperature
cy-cling, causing reflective cracking in the
field, as will be shown later.
Retainingjleribility in cold weather.
All membranes stiffen in the cold and
unde rgo gradual crystallization at very
low temperatures. i.e., -25'C ( -13'F) or below. Such embrittlement will reduce the membrane's ability to withstand static
ｬｯ［Ｎｾ､ｩｮｧ＠ and dynamic shock without crack-ing. The change in performance that results from embrittlement is measured
- by
determining tensile strength andelon-gation capacity of free film specimens.
Figures B and C present the trends in variation of tensile strength and elonga-tion capacity as the temperature is de-creased to -40'C ( -40'F). Tensile strength increases and elongation decreases with decreasing temper.1ture. Percentage elon-gation values at -20'C ( -4'F) for ure-thane 1 and the solvent-borne epoxy-urethane blend, neoprene, and asphaltic mastic samples are extremely low, show-ing a considerable decrease from room temperature values. The better response of urethane 3, however, is typical oflong chain polyurethane rubber-based elas-tomers.
The results show the drastic reduc-tions in elongation and tensile strength at temperatures below -20'C ( 4F). These changes may significantly increase the strain at the bond interface during low-temperature cycling, promoting de-bonding or tearing of the membrane.
Table 1. Tensile strength and elongation of free film membrane samples
Membrane Tensile Strength Elongation at Failure Recovery from
System (MPa) (%) Elongation (%}
Urethane 1 (51) 22.7 300 87.1 Urethane 2 (52) 3.2 370 98.5 Urethane 3 (53) 3.0 700 93.7 Epo>.:y-urethane blend (54) 4.8 140 .58.0 Neoprene (55) 8.6 760 69.4 Asphaltic mastic (56) 0.18 1070 88.0
Figure B. Effects of cold temperature on elongation
60 - A - 51 - 5 4 <: r:>. 40 ::;:
io
c: 2: V5ｾ＠
20 c: ｾ＠ 0 -50 -40 -30 -20 -10 0 10 20 30 Temperature (C0 )ｆＢｾｧｾｾｲ･＠ C. Effects of cold temperature on tensile strength
1200 , -- -- --- -- -- -- -- -- --- ---, ----6- 51 - o - 54 -o-52
-+-
S5 900 -o-53ｾ＠
c: .!2 600 ｾ＠c: 0w
300 -40 -30 -20 -10 0 10 20 30 Temperature (C0 )Figure D. Relationship between coating thickness and crack-bridging abifrly
15
f
95% Confidence
t
Limits
10
5
..
0 0.5
11.5
Coating Thickness (mm)
Table 2. Tensile adhesive strength to concrete (MPal Membrane Urethane 1 (S1) Urethane 2 (S2) Urethane 3 (S3) Epoxy-urethane blend (S4) Neoprene (S5) Asphaltic mastic (S6) Control
Adhesive s!rength to concrete. Wa-terproofing membranes must adhere well to concrete. Consequently, many job specifications stipulate proper surface preparation according to membrane manufacturers' instructions and require that the acceptance of the concrete sur-face texture and cleanliness be subject to the approval of the applicator.
A
successful membrane must be ableConcrete Substrate w/c = 0.45 Adhesive Strength, MPa Air Entrained Non Air Entrained
4.88 4.27 2.36 1.45 1.85 1.59 3.82 3.31 3.75 3.56 0.26 0.26 4.88 4.88
to wet out the concrete surface (even the laitance) to achieve adhesion . This re-quirement should be satisfied under nor-mal, humid, or any other conditions to which the deck will be subjected.
Tensile bond strength values for con-crete coated with waterproofing
mem-bmnes are presented in Table 2.
Gener-ally,
'the adhesive strength of thewater-proofing membrane is c:onsiderably less
100 Th e Construc:tion ｓｰｾ＼ＮＮ ﾷ ｩｦｩ･ｲ＠ I ｄｐ ｣ ｴＢｭ｢ｾｲ＠ ＱＹｾＩＲ＠
2
2.5
Concrete Substrate wlc = 0.55 Adhesive Strength, MPa Air Entrained Non Air Entrained
3.47 4.88 2.25 1.80 1.36 1.56 3.42 3.16 2.55 2.88 0.14 0.11 4.32 4.88
than the tensile strength of the c:oncrete. Bond strengths vary with c:oncrete type, typically decreasing with an increase in the water-cement ratio or with air en-trJ..inment.
With the exception of the values ob-tained for the asphaltic system, the re-sults show that thin adllesive-type mem-branes pro-..ide an adequate bond to the concrete substrate.
Table 3. Crack-bridging ability Membrane Urethane 1 (Sl) Urethane 2 (S2) Urethane 3 (S3) Epoxy-urethane blend (S4) Neoprene (SS) Asphaltic mastic (S6)
Notwithstanding their inherent capa-bility to bond well to concrete, poor surface preparation and adverse applica-tion condiapplica-tions can cause dry or liquid-filled blisters to fonn. De bonding invari-ably follows.
Bistering is in fact one of the most common causes of failure related to ad-hesion. Blistering is usually caused by the penetration of moisture through the
Concrete Substrate w/c
=
0.45 Air Entrained Non Air Entrainedfail fail pass pass pass pass fail fail pass pass fail fail
coating into areas of poor adhesion. Other conditions that can cause blisters are incompatibility between topcoat and base coat, solvent entrapment, and use of the wrong primer.
There are two types of blister: (1) those formed from the substrate, with the coat separating from the substrate, and (2) those formed ?etween coats, e.g., where the top coat separates from
Concrete Substrate w/c
=
0.55 Air Entrained Non Air Entrainedfail fail pass pass pass pass fail fail pass pass fail fail
Photo 1, top. BlisteTing is usually caused by penetration of moisture through the coating in areas of poor adhesion.
Photos 2 and 3. These specimens failed due to the asphaltic membrane's inability to withstand free-....elthau; action.
an undercoat (circular blisters). The lat-ter type is shown in Photo 1, page 101.
Crack-bridging ability. Concrete substrate cracks can move, affecting the perform<mce of membrane systems by reflecting through the membrane and allowing water to penetrate to the deck. Liquid-applied membranes are sus<:ep-tible to this problem because of their continuous adhesion to the substrate. They are subjected to ｴｲ･ｭ･ｮｾｯｵｳ＠
stresses when a moving crack develops where none existed at the time of appli-cation.
These problems are likely to occur when the cast-in-place structure is ex-posed to direct sunlight and the mem-brane is applied before sufficient time has passed for all shrinkage cracks to . ·occur. Other factors that influence a membrane's crack-bridging
characteris-tics are low-temperature flexibility and
film
thickness. The importan<:e ofmem-brane thickness to crack bridging is shown in FigureD, page 100.
Low-temperature flexibility is tested at temperatures of -26' C (-15'F). A 1.5
mm (0.06 in.) coating is applied to a pair of mortar blocks, allowed to cure, then tested as the opening between the blocks changes from zero to 2 mm (Y1fi in.). Materials that survive 10 cydes \\ithout cracking or losing adhesion are consid-ered to have passed the test.
Data in Table 3, page 101. shows that three waterproofing membranes-ure-thane 1, the epo>-y-uremembranes-ure-thane blend, and the asphaltic mastic-failed after 10 cycles of elongation, which is not sur-prising since these membr.mes do not readily accommodate movement at low tempemtures (see Figure C, page 99).
I 02 T h ｾ＠ Co n s t r 11 c t i u '' S p ｾ＠ e i fi t• r I D t• t.· ｾ＠ m h t:" r l U U 2
This is a laboratory test, and while it is severe and should be a good pre.dictor of field success, membranes that pass it are still subject to reflective cracking. Such failure is probably due to the defects incorporated into the membrane by sub-str.tte movement during its early curing. When elastomeric membr.tnes are ap-plied under field conditions. they are likely to be subjected to mo\·ement in the early curing stages, prior to develop-ing full elastomeric properties. Conse-quently, defects that
will
ser\'e as poten-tial sites for deterioration develop. Furthennore, initial daily thennal cy-cling can increase the number of defects within the membrane before it is fully cured.Freeze/thaw stability. Exposed con-crete decks need to be protected from <;orrosion-related deterioration as well as
.•
Table 4. Length change after 100 freeze/thaw cycles 1%1
Membrane w/c = 0.45 w/c = 0.55
Air Entrained Non Air Entrained Air Entrained Non Air Entrained
Urethane 1 (S1) 1.323 0.004 1.047 0.041 Urethane 2 (S2) 0.006 0.003 0.006 0.003 Urethane 3 (S3) --0.038 -0.023 -0.017 -0.013 Epoxy-urethane blend (S4) 0.628 0.010 1.371 0.019 ｾ･ｯｰｲ･ｮ･＠ (S5) 0.017 -0.012 -0.031 --0.018 Asphaltic mastic (S6)
.
12.721.
12.712Before choosing elastomeric membranes to protect concrete slabs in parking garages, specifiers should rwt fail to ecaluate products' field perfonnance.
the surfaee sealing that results from freeze/thaw eyding of saturated eonerete. Damage to the membrane ean result if water penetrates it and saturates the conerete/membrane interface.
Subse-quent exposure to freezing conditions will eause the membrane to flake off, with a thin layer of concrete adhering to its underside.
Also, moisture movement through the eoncrete to the surface may push off the membrane under similar drcumstances. Thus, the membrane/concrete interface must remain as dry as possible to ensure the system remains intact and imperme-able to water under all expected eondi-tions.
The percentage increase or decrease in length of coated concrete prisms ob-served after 100 eycles of freezing and thawing is presented in Table 4. It is generally aecepted that increases in length above 0.1 percent represent the onset of fracturing in mortar specimens.
With the exception of asphaltic mas-tic, all the membrane systems investi-gated here improved the freeze/thaw durability of air-entrained concrete. Only urethanes 2 and 3 and the neoprene sample improved the durability of non-air-entrained concrete, however, indicat-ing that water indicat-ingress may have occurred in urethane 1 and in the solvent-borne epoxy-urethane blend due to pinhole and blister formation. Photos 2 and 3 (page 102) illustrate the poor resistance of the asphaltic membrane.
Evaluation
The foregoing discussion was intended to draw attention 'to the critical proper-ties of elastomeric membranes used to protect concrete slabs in parking garages. Membrane selection should always be based on a careful study of material prop-erties. And before a product is chosen, the specifier should not fail to evaluate its performance under field conditions similar to those ex-pected in the job at hand.+
References
"A Guide to the Use of Waterproofing, Damp-proofing, Protective and Decorative Barrier Systems for Concrete," Report ACI 515.1R-79. Manual of Concrete Practice, pt. 5. Detroit, Michigan: American Concrete Institute, 1984. &aluation of Elastomeric Membrane Systems Used in Parking Garage Protection, Client Re-port CR 6145.3. Ottawa, Canada: Institute for Research in Construction, National Research Council of Canada, February 1992.
Evans, R.M. "Test Methods Used in ASTM Specifications for Liquid-Applied Elastomeric Membranes for Waterproofing Concrete." Building Deck Waterproofing. ASTM STP 1084. Philadelphia, Pennsylvania: American Society for Testing and Materials, 1990. Hunnicut, J.M. "Parking Deck Deterioration:
The Reasons Why" (Concrete Construction 21, no. 9).
Jacobson, N.C., )r. "A Case Study of Parking Deck Deterioration Methods" (Parking, Win-ter 1982).
Mailvaganam, N.P. "Elastomeric Parking Deck Membranes" (Concrete Intemational, 8, no. 10).
Monroe, D.C. "Reflective Cracking and Cold, Liquid-Applied Elastomeric Deck Coating and Membrane Systems: Practical Considerations from Field Observations." Building Deck Wa-terproofing, ASTM STP 1084. Philadelphia, Pennsylvania: American Society for Testing and Materials, 1990.
Oosterbroek, M. Lammers, R.J., and Yen der Van, L.C.J. "Crack Formation and Stress De-velopment in an Organic Coating" (joumal of Coatings Technology, June 1991).
Waterproof Membranes for Protection of Con-crete Bridge Decks, Laboratory Phase (Project 12-11), National Cooperative Highway Re-search Program Report no. 165. Washington, D.C.: Transportation Research Board. Na-tional Research Council, 1976.
NOEL P. MAILVAGANAM is a senior research officer \\ith the Canadian National Research Council's Institute for Research in Construction (IRC). Mr. Mailvaganam, who is head of the Polymer Croup, has co-authored and edited three books on chemical admixtures and on concrete repair and protection. PETER G.
COLUNS, BSC, is a technical officer with the IRC's Polymer Croup.
