NATIONAL BUREAU OF STANDARDS REPORT

OF

MATERIALS USED IN WATERPROOFING SYSTEMS ON UNDERGROUND STRUCTURES

by

William W. Walton

Thomas H. Boone

William C, Cullen

Austin J. Turner

-<NBS>

U. S. DEPARTMENT OF COMMERCE

NATIONAL BUREAU OF STANDARDS
NATIONAL BUREAU OF STANDARDS

The National Bureau of Standards 1 was established by an act of Congress March 3, 1901. Today,

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NATIONAL BUREAU OF STANDARDS REPORT

m% PROJECT NBS REPORT

1004-12-10446

\ o-.>V

.,nC~

ox 30 June 1962 7542

PROGRESS REPORT

ON

MATERIALS USED IN WATERPROOFING SYSTEMS ON UNDERGROUND STRUCTURES

by

William W. Walton

Thomas H. Boone

William C. Cullen

Austin J. Turner

Sponsored by

Office of the Chief of Engineers

Department of the Air Force

Bureau of Yards and Docks

NATIONAL BUREAU OF STA

Intended for use within the G

to additional evaluation and re listing of this Report, either in the Office of the Director, Natl however, by the Government a

to reproduce additional copies

IMPORTANT NOTICE

)gress accounting documents Approved for public release by the ,a| b published it is subjected

Director of the National Institute of 3n is obtalned , n siting from Standards and Technology (NIST) uch permission is not needed, on October 9, 2015. re P ared if that agency wishes

<NBS>

U. S. DEPARTMENT OF COMMERCE

NATIONAL BUREAU OF STANDARDS

PROGRESS REPORT OF

MATERIALS USED IN WATERPROOFING SYSTEMS ON UNDERGROUND STRUCTURES

1 . INTRODUCTION

The use of underground structures has increased in recent years and the waterproofing of these structures is of paramount importance. Multiple-ply, bituminous, built-up membranes have earned an excellent reputation in this respect.

However, other organic materials in various forms (sheet, coatings, etc.) have

recently shown promise to perform the same function and eliminate some of

the difficulties inherently connected with the application and performance of

a hot-applied, built-up membrane.

The many factors relating to application techniques and ultimate performance

of the newer systems have been recognized by the agencies of the Defense

Department. Heretofore, little unbiased information has been available to

assist the personnel charged with design and maintenance responsibilities.

Therefore, in response to a request of the Chief of Engineers, U. S. Army;

Directorate of Civil Engineering, U. S. Air Force; and the Bureau of Yards

and Docks, U. S. Navy, a program was conducted to investigate the perfor- mance of waterproofing materials and systems, both in the laboratory and in

the field.

This report gives the results of the laboratory work and the findings obtained during the field surveys in Fiscal Year 1962.

2. MATERIALS

The first choice of materials for laboratory study were those used or specified for use in facilities that were visited. Later in the program,

additional materials and systems were obtained from various sources.

At two sites which were visited, hot-spray vinyl coatings, 20 to 30 mils

thick, were observed. (See Sections 4.1.1 and 4.1.2.) At the first site,

the material was designated as "Ren Plastic RC 920", manufactured by the

Ren Plastics, Inc., Lansing, Michigan. At the second site, the material

used for waterproofing the underground control centers was "Gold Bond GP

Vinyl Epoxy Primer" with a 20-mil thick coating of "Vinylelastic" placed

over the primer. These materials are manufactured by the Coloron Division,

Kish Industries, Inc., Lansing, Michigan.

2

The materials under investigation have been divided into three categories:

built-up, sheet, and coating. They are discussed below. A list of the

materials and the manufacturers which have been contacted by this

laboratory is given in Table I.

2.1 Built-Up

Built-up systems consisting of alternate layers of felt and hot bitumens have

a long history of successful performance for below-grade waterproofing. The

systems vary, however, with the type and method of applying the bitumen and

the number and types of felts or cloth used. In addition to the bituminous

materials, high-solids epoxy, epoxy esters, and coal-tar epoxy are used in some cases with membranes and are therefore included in the built-up

systems.

2.2 Sheetings

Both rubber and plastic materials ranging from 8 to 100 mils are included

in this category. The most popular plastic sheeting is polyvinyl chloride,

although the following materials have been suggested: high-density

polyethylene, polyesters, vinylidene chloride-vinyl chloride copolymer, and

polystyrene. These latter materials have not been emphasized by the

plastics industry for this use because of high cost, properties, or application techniques.

2.3

Coatings

The waterproof coating commonly used in the silo construction thus far

observed was a vinyl chloride dispersion applied by a hot-spray technique

to an epoxy-primed surface. One-coat, epoxy-vinyl systems, high-solids

epoxies, epoxy esters, and chlorinated rubber are also being considered

for use.

3. APPLICATION METHODS

In addition to possessing the desired physical properties, a material for use in underground waterproofing systems should be capable of being applied

by conventional techniques.

TABLE I - MATERIALS

Designation

mple Type Manufacturer Trade Names Brief Discription

Built-up Membrane

5 Asphalt emulsion

and glass fabric

Flintknote Co.

Industrial Div.

Yellow Jacket

& Asphalt Emulsion C-13-E

3 ply system of

fabric and emulsion

6 Hot asphalt and

asphalt felt

” — 3 ply system of

15 lbs. asphalt felt

and hot asphalt

7 Hot coal tar and

coal tar felt — — 3 ply system of

15 lbs. coal tar felt

and hot coal tar

8 Asphalt emulsion

and glass fabric

Lion Oil Co. Nokorode

Seal Kote

3 ply system of

fabric over asphalt

base primer

15 Coal tar epoxy

and glass fabric

Pittsburgh

Chemical Co.

Tarset (R)

Standard

2 coat system of

glass fabric and

coal tar solution over primer about

8 to 10 mils

16 Coal tar epoxy

and glass fabric

Pittsburgh

Chemical Co.

Tarset Epoxy

x-403

2 coat system of

glass fabric and

coal tar without

primer about 65 to

90 mils

17 Hot coal tar

enamel and glass

fabric

Pittsburgh

Chemical Co.

Plasticized

Enamel

2 ply system of hot

coal tar enamel and

glass fabric

TABLE I - MATERIALS (CON’T)

Sample Type Manufacturer

Designation

Trade Names Brief Discription

Sheeting Membrane

2 Polyvinyl

chloride

Lexsuco Co. Lexsuco Vinyl

Waterproofing

8 mils thick sheet

applied with "Lexsuco

Adhesive"

3 Polyvinyl

chloride

Visking Co. KDA-2265

Black-35

8 mils thick sheet

applied with "Boxer

Cement"

4 Rubber-plastic Rubber & Plastic

Compound Co.,

Inc.

Nervastral &

Seal Puff

8 mils thick sheet

applied with "Nerva

Plast Cement"

9 Rubber-plastic Rubber & Plastic

Compound Co.,

Inc.

Nervastral &

Seal Puff

10 mils thick sheetapplied with "Nerva

Plast Cement"

10 Rubber-plastic Rubber & Plastic

Compound Co.

Inc.

Nervastral &

Seal Puff

15 mils thick sheet

applied with "Nerva

Plast Cement"

11 Rubber-plastic Rubber & Plastic

Compound Co.

Inc.

Nervastral &

Seal Puff

20 mils thick sheet

applied with "Nerva

Plast Cement"

12 Rubber-plastic Rubber & Plastic

Compound Co.,

Inc.

Nervastral &

Seal Puff

30 mils thick sheet

applied with "Nerva

Plast Cement"

18 Rubber-plastic Amercoat

Corporation

Amercoat (TLock)100 mils thick with

ribbing that are mechanically embedded

in concrete

Coated Membrane

1 Hot spray on vinyl

Coloron Div. of

Kish Industries

Vinylastic 20 mils thick hot

spray polyvinyl chloride applied over

epoxy primer

14 Rubber base

compound

Tufcrete Co. Elastomeric

Coating

2 coat system about

3/8" thick

3 3.1

Mopping

Coal-tar enamels, asphalt and coal-tar pitch built-up membranes are always

applied hot, and this type of application presents some hazard when working

in confined areas. The heating equipment must be located fairly close to

the area of application, because too low a temperature at the time of

application results in poor bond and inadequate penetration of the felt or cloth.

3.2 Adhering

The flexible plastic sheet systems are bonded and, in some cases, sealed

at overlapping ends by thermoplastic adhesives. A thermoplastic adhesive

is specified because such an adhesive can closely approximate the properties

of the sheet and is likely to better withstand the stresses developed during

the expansion and contraction that might occur. These adhesives dry by

solvent evaporation, leaving the solid adhesive in place. The nature of

the adhesive required is determined by the temperature and other physical

requirements of the application and the nature of the materials to be

"bonded. Besides involving fire and toxicity hazards, the use of adhesives

in the field requires careful surface preparation and application.

3.3 Spraying

The vinyls, plastisols, and epoxies in suitable solvent systems may be

sprayed with conventional spraying equipment. Equipment is available to

mix two component systems in the right proportions at the nozzle, to

preheat the material, and to heat the material at the nozzle in order to

facilitate faster cure or set. Skilled personnel, with a good understanding

of the equipment and material, are required.

3.4

Mechanical

A 100 mil thick polyvinyl chloride with T-extensions of ribbing, spaced

at 2 1/2-inch intervals relies on a mechanical bond. This plastic lining

material is placed on the concrete side of the forms before pouring the

concrete, with the smooth side toward the forms. The concrete flows

around the ribs, thus making the plastic an integral part of the finished

structure.

- 4

-

4. PROPERTIES

4.1 Field Inspections

) Through the cooperation of the Corps of Engineers Ballistic Missile

Construction Office and the Bureau of Yards and Docks, the following field

inspections were made in Fiscal Year 1962:

Titan I site at Larson Air Force Base

Minuteman sites at Malmstrom Air Force Base

Titan II sites at Little Rock Air Force Base

Miscellaneous Structures

At each location, the Area Engineer was contacted and discussions were held

with staff and field engineers on methods and materials used for waterproofing the structures.

4.1.1 Larson Air Force Base

A visit was made to Titan I missile launching complex 1-C to observe systems

of waterproofing on underground silos, tunnels, and adjoining structures.

With the exception of a few structures near the surface, all work had been

covered over.

The silo structures were waterproofed with a two-coat system. A hot-spray

primer was applied at a rate of approximately 200 sq. ft. per gallon of a material identified as RC 900, after which a second coat of a material known

as RC 920 was applied by a hot-spray technique to a thickness of about 30

mils. The coating system was reported to be a plastic membrane waterproofing of epoxy-polyvinyl chloride as manwfactured by Ren Plastics, Inc.,

Lansing, Michigan.

The corrugated steel utility tunnels were coated with factory-applied

asphalt-asbestos mastic.

The adjoining structures were waterproofed with a five-ply asphalt-felt

system and protected with l/2-inch fiberboard.

The site was surrounded by irrigated fields supplied by canals from the

Columbia Basin Project and the complex was designed for a water table

within a few feet of the surface.

<

5

At the time of the visit, the leakage of water into the structures and

tunnels at this site was a serious problem. Water was being pumped

from the site at a rate of 240,000 to 255,000 gallons per day during

the period of 29 July to 9 August. There were numerous leaks around

bolts in the tunnels. Leaks were also noted at tunnel junctions.

Minor leaks were encountered in the concrete structures, generally at

points where bolting into walls had taken place, or where steel

members had been welded to ring beams set in the concrete structures.

4.1.2 Malstrom Air Force Base

A visit was made to six Minuteman launch silos and four control centers.

The areas visited included all phases of construction.

The control center structures were being waterproofed with a two-coat

system. First a hot-spray primer of a material known as "Gold Bond GP

Vinyl-Epoxy Primer" was applied to a dry film thickness of 1 mil, and

second a hot-spray finish coat called "Vinyle lastic" was applied at a dry film thickness of 20 mils. The complete system was reported to

be "Lifecoat Vinylelastic Waterproofing Membrane", as manufactured by

Coloron Division of Kish Industries, Lansing, Michigan. The primer

coat was, in some cases, used as or in place of the concrete curing

compound. No protective b®ard was used for back fill. Blisters were observed on some surfaces, but they were reported to disappear in time.

Some small areas (1/4 to 1/2 inch) were torn on the membrane at one control center being back-filled.

4.1.3 Little Rock Air Force Base

Three Titan II Missile Sites (2, 15, and 4) were visited at Little Rock

Air Force Base, Little Rock, Arkansas. The three sites were at various

stages of construction, with site 4 most nearly completed.

The following observations were made during the visit:

Access Port . The access port was a reinforced concrete structure ex- tending about 35 feet underground. The waterproofing system consisted

of priming the relatively smooth concrete surface with an asphalt

cut-back primer and applying a 5-ply asphalt built-up membrane horizontally. A fiberboard insulating material was used to protect the

membrane from damage during the backfill operation.

The condition of the membrane waterproofing varied from site to site. On

site 2, the application was excellent, while on site 4, it was poor. The

poor condition was evidenced by a lack of adhesion between the plies of

felt and severe slippage of the membrane at one area, and could be attributed to application difficulties.

Some difficulty was also experienced with the exposed fiberboard protection

of the membrane. In many cases it was observed that the material had

curled with a subsequent loss of adhesion to the membrane and hence gave

little protection to it. It was suggested that this condition could be

eliminated by coating the fiberboard with either hot asphalt or a cold

asphalt coating to prevent moisture absorption and the resultant curling.

A point of weakness in the waterproofing system was observed at the

junction of the access port and the electromagnetic shield on the blast

lock. The original specification did not call for flashing at this

point and leakage developed. Currently, a 12-inch strip of asphaltsaturated felt embedded in and coated with a fibrated asphalt emulsion is

being successfully employed as a flashing. It was felt that this is a temporary measure and it was suggested that a more permanent type of

flashing be designed.

Silos . The construction and waterproofing of silos were also observed at

Sites Nos. 2, 4, and 15. The silos were constructed of heavily reinforced

concrete and extend about 145 feet below the surface. No waterproofing,

per se, was applied to the silo construction. However, a 1/4-inch welded

steel plate which serves as an electromagnetic shield and completely

encloses the silo, blast lock and control center also acts as the waterproofing member.

It was reported that water leakage had occurred both in the silos themselves and outside the silos in the vicinity of the intake and exhaust

ports. There was no question that failures in the form of breaks in the

EM shield had occurred. Since it was impossible to attaet the problem

from the outside of the silo, greeting from the inside was clearly

indicated and successfully accomplished.

Grouting with a chemical solution identified as Halliburton Pressure

Grouting was the system used and its use was reported as successful on

the silo at site No. 2.

- 7

-

The grouting process at Site No. 5 was observed during the inspections.

The system consisted of drilling a 2-inch hole through the 4-foot thick

concrete wall and injecting the chemical grout under pressure into the area between the EM shield and the concrete wall. The grout initially

has a viscosity of water and thickens with time to seal openings in the

concrete.

4.1.4 Small Underground Structures

A visit was made to observe the application of a membrane waterproofing

system on a two-story buried concrete structure.

The concrete surface was coated with creosote primer and waterproofed with

a four-ply, coal- tar-pitch membrane. The membrane consisted of three

layers of felt and one ply of cotton fabric mopped to the primed concrete

and to each other with hot pitch. A 1/2-inch fiber board was placed for

backfill protection.

4.2 Laboratory Inspections

The properties considered to be of greatest importance for the intended

application in underground waterproofing systems are as follows:

Water Resistance

Water-vapor permeability

Water absorption

Water-pressure resistance

Resistance to Soil Conditions

Acids, bases, and salts

Fungi and bacteria

Rodents and insects

Strength

Tensile strength

Elongation

Toughness

Tear resistance

Puncture resistance

Tear-impact

8

The properties and methods of test for water-pressure resistance, strength

and toughness are discussed in the following sections. Tables II, III, and

IF list results of these tests. Table I may be referred to for the identification of the samples that were tested.

4.2.1 Sample Preparations

All samples tested thus far have been received directly from the manufacturers and applied to concrete panels or prepared in a "free film" form

according to directions supplied by the manufacturer. The coating-type

materials were applied with a brush to the thickness specified by the

manufacturer. All materials were dried or cured for the specified time

before testing.

4.2.2 Water Resistance

An apparatus has been designed and constructed to subject membranes in

the laboratory to conditions simulating those encountered in the

field (see Figure 1). The apparatus permits the waterproofing membrane,

backed by concrete, to be exposed to water pressures of varying amounts.

This treatment is designed to simulate the water-head existing at various

depths underground. The apparatus also permits exposure of the membrane

to various sizes and types of gravel under varying pressures independent

of the water pressure. Table II lists results of tests on some of the

materials under one set of test conditions.

4.2.3 Strength

Tensile Strength . Good tensile strength is of basic importance in any

material that may be subjected to stress and strain during handling or service. Measurement of this property of plastic sheets, films, or built-up materials was made by ASTM Method D 882, Method B, in which a constant rate of jaw or grip separation was employed. The test specimen

was a strip of uniform width and thickness and 4 inches or more in length.

The width of specimen was chosen to allow failure to occur well within

the load capacity of the machine. A rate of cross-head motion of 20

inches per minute was used. Thickness and width were measured at several

points and the minimum cross-section was recorded. Tensile strength was calculated by dividing the maximum load in pounds by the original minimum

cross-sectional area in square inches. The average strengths in two

directions are reported from specimens made at right angles to each other.

The results are listed in Table III.

TABLE II - WATER PRESSURE - BACKFILL

LOAD TEST

(Water pressure = 60 lbs.; Backfill pressure = 600 lbs.

Sample No. Results

5

6

7

Built-up Membrane

2 / Failed—'

Passed

Passed

Sheeting Membrane

2 Failed

3 Failed

4 Failed

9 Failed

10 Failed

11 Passed

12 Passed

18 Passed

Coated Membrane

1 Failed

1 / Pressure applied to sample over a 4- by 6-l/2-inch area wath No. 4

pea gravel.

2/ The word ’’ failed” indicates that the membrane would permit water to

leak through to the concrete within four hours under the above test

conditions.

TABLE III - STRENGTH

Sample No. Thickness Breaking Strength Tensile Strength Elongation

lbs. psi 1o

Mils. A dir. B dir. A dir. B dir. A dir. B dir.

Built-up Membranes

5 75 30 18 670 410 0 0

6 225 42 29 290 250 0 0

7 190 20 19 180 170 0 0

Sheeting Membranes

2 9 18 18 3600 3600 300 270

3 8 11 9 2190 1720 240 220

4 20 32 25 2700 2070 300 280

9 10 13 11 2260 1880 270 230

10 16 27 19 2890 I960 290 280

11 21 34 25 2540 2030 300 300

12 30 44 38 2700 2140 350 330

18 125 51 49 4100 3860 340 330

Coat Membrane

1 30 25 24 1430 1350 230 230

TABLE IV - TOUGHNESS

Sample No. Thickness

Tear

Resistance

Puncture

Resistance

45° Tea

Impact

lbs

.

mils A dir B dir ft ft

Built-up Membranes

5 80 15 15 3 3

6 200 34 29 3 8

7 215 20 18 2-1/2 8

Sheeting Membranes

2 9 3 3 2 <2

3 8 2 2 2-1/2 2

4 21 6 5 7 2

9 10 2 2 3-1/2 2

10 16 5 3 5 2

11 22 6 5 7 2

12 30 7 7 >8 2

18 104 46 41 >8 >8

Coated Membranes

1 30 10 9 >8 3

9

Elongation . A moderate elongation is desirable for ease of handling and

fitting materials and for keeping stresses generated during installation

or service at relatively low levels. While the specimens were being

tested for tensile strength, the elongation was recorded to the moment

of rupture. The percent elongation was calculated by dividing the

elongation at the moment of rupture by the original length and multiplying

by 100. The results of the determinations are reported in Table III.

The tests were performed on specimens cut in two directions at right

angles to each other.

4.2.4 Toughness

The property of toughness, while closely related to strength, implies

certain additional qualities. Tear resistance, puncture resistance, and

tear-impact are of particular importance.

Tear Resistance . A good tear resistance is desirable for fitting materials

and for resisting damage during service. A constant rate grip separation,

as described in ASTM D-1004-61, was used to determine the tear strength by

measuring the maximum load required to tear through a specially-shaped

die-cut specimen and is expressed as pull in pounds per inch of thickness.

The specimen had a 90 degree off-set, rounded on the outer edge and forming

a right angle at the center of the inner edge, so that a high stress concen- tration was produced at the center of the specimen when the load was applied.

The tear strength value is therefore an indication of the notch sensitivity

of the material as well as a function of its tensile strength, elongation,

and shear strength. The results of the tear strength are given in Table IV.

Puncture Resistance . A good resistance to puncture would prevent damage to

the membranes such as might result from accidental dropping of tools or in back-fill operations. In this test, 10- by 10-inch specimens were held firmly by a wooden frame with a 6- by 6-inch opening in the center.

A 200-gram steel dart with a 1/8-inch diameter ball point was dropped

vertically onto the center of the specimen. The distance in height that

the material would withstand the drop without causing puncture completely

through the specimen is recorded in Table IV.

Tear Impact . Another feature of considerable importance is the resistance

of the membranes to impact when placed against a concrete surface. In this

test, the materials were placed on concrete panels as in actual field

applications. The concrete was set up at 45 degrees from the horizontal

with the membrane facing upward, A 220-gram steel dart with a 3/4-inch

diameter rod, rounded at the end, was dropped vertically onto the specimen.

The distance in height that the material would withstand the drop without

breaking or tearing the membrane through to the concrete is recorded in

Table IV.

10

5 . SUMMARY

Visits were made to Titan I, Titan IX, and Minuteman missile sites to observe

the performance of waterproofing materials in actual use and to ascertain

the practical problems connected with waterproofing techniques in the field.

Some of the difficulties could be traced to design deficiencies such as the use of bolted joints in the cableways of the Titan missile sites or the lack

of water stops or flashings where needed. These deficiencies are being

corrected in present construction. Other problems could be traced to the

field conditions. For example, limited working space necessitated carrying

the hot asphalt used in built-up membrane waterproofing a distance so great

that it became too cool for best application. Another example is the use

of curing compounds on the concrete to conserve the water that would be

required for curing. The use of these compounds often prevented proper

bonding between the concrete surface and an epoxy primer used with a hotspray polyvinyl chloride-epoxy resin waterproofing treatment. This problem

was solved by substituting the epoxy primer for the curing compound.

The polyvinyl chloride-epoxy resin treatment still presents an unsolved

problem of occasional blisters. Working space, ventilation, condition of

the concrete surface, back-fill operation, time schedules, and availability

of experienced personnel are some of the important field conditions that

must be considered in the solution of a waterproofing system.

The laboratory data are insufficient for specific conclusions, but they

do indicate general trends. Samples with breaking strengths 32 pounds

or lower failed in the simulated water pressure-back-fill load test with

the exception of sample No. 7, which had a breaking strength of 20 pounds

in one direction and 19 pounds at a right angle direction. Sample No. 11,

which also passed the simulated test, had a breaking strength of 34 pounds

in one direction and 23 pounds at a right angle direction.

The percent elongation showed no correlation with the simulated test, but

this property may have some importance during installation.

Samples with high tear resistance, puncture resistance, and 45° tear

impact resistance passed the simulated test, but there are a number of

exceptions. Sample No. 4, which failed this test, had the same values

for all three properties as sample No. 11 which passed. Also, sample

No. 5, which failed the simulated test, had a much higher tear resistance

than either samples No. 11 and 12, although it should be noted that its

value was lower than samples Nos. 6 and 7 of similar type.

The significance of any of these tests, including the water pressure-backfill load test, has not been established.

USCOMM-NBS-DC

air outlet

figure I. Simulated service test apparatus. The apparatus

was designed to simulate conditions to which waterproofing systems are subjected.