Plexideck bridge deck overlay installation guide

PLEXIDECK BRIDGE OVERLAY SYSTEM FOR
CONCRETE BRIDGE AND PARKING DECKS

1.0 SCOPE
This guide provides recommendations on the proper use and application of the PLEXIDECK
Bridge Overlay System. Please consult Plexicoat America’s standard specifications, product data
sheets and material safety data sheets (MSDS) for additional information on each component.
2.0 CONTENTS
4.0 Features of the PLEXIDECK Bridge Overlay System
3.0 DEFINITIONS
Thin Polymer Overlay - Non-cementitious, concrete bridge deck topping material in which graded
aggregates are bound together in a slurry with a polymer binder. The system is broadcast with a
wearing course aggregate. Thin polymer overlays, applied in layers up to 3/8", extend the life of
bridge decks by increasing waterproofing and skid resistance characteristics, by adding minimal
deadweight and by dramatically reducing lane closure times for the motorist.
PLEXIDECK - Plexicoat America’s brand of methacrylate concrete restoration and repair
materials for crack sealing, bridge overlays and polymer concretes. Products are based on
reactive esters of acrylic and methacrylic acid including methyl methacrylate (MMA).
PLEXIDECK Flexible Bodycoat Filler Component - Blend of specially graded fillers used with
PLEXIDECK Flexible Bodycoat Resin Component and Powder Hardener to form the slurry layer
of the overlay system.
PLEXIDECK Flexible Bodycoat Resin Component - Flexible methacrylate reactive resin used with
PLEXIDECK Flexible Bodycoat Filler Component to form the slurry layer.
PLEXIDECK Primer - Methacrylate reactive resin used to treat properly prepared concrete
substrates prior to receiving the PLEXIDECK Bridge Overlay System.
Powder Hardener - 50% dibenzoyl peroxide (BPO) in granulated powder form used in small
quantities to initiate the cure of PLEXIDECK resins.
Wearing Course Aggregate - Specially graded, angular, hardwearing natural stone that is
broadcast into the PLEXIDECK Flexible Bodycoat slurry and serves as the wearing course for
vehicular traffic.
Plexicoat America, LLC • 1708 Whitehead Road, Suite 102B • Baltimore, MD 21207
4.0 FEATURES OF THE PLEXIDECK BRIDGE OVERLAY SYSTEM

4.1 How PLEXIDECK Differs From Other Types of Thin Polymer Overlays
Methacrylates such as PLEXIDECK differ significantly from other systems including epoxies,
polyesters and derivatives of these resins.
PLEXIDECK cures via an addition polymerization mechanism. This is initiated by the
decomposition of the Powder Hardener by the amine component within the PLEXIDECK Primer
or PLEXIDECK Flexible Bodycoat Resin Component. Free radicals are formed and used to link
the various monomer, polymer and diluent constituents by their unsaturated sites into a three-
dimensional polymer network. This reaction is temperature-dependent, but can proceed easily
below 50° F unlike other chemistries. Also, during the reaction, all hardener is consumed and the
polymer is fully formed within a one-hour period. There is no potential for an excess of unreacted
components or extended cure that is typical of other systems. When used correctly, cure is
thorough and consistent.

4.2 The PLEXIDECK Advantage

Fully cures in one hour in temperatures ranging from 40ºF to 104º F Provides for rapid return of construction areas to normal traffic, contributing directly to worker and driver safety Creates an impervious surface to resist moisture Offers a cost-effective alternative to other overlay systems or deck replacement projects Possesses excellent long-term flexibility and compatibility with concrete substrates Meets or exceeds EPA requirements for VOC emissions Weighs less than 3 lb/ sq ft to reduce dead load on older bridge structures
5.0 ESTIMATING

5.1 General
All estimates are based on application of products at 40° F and higher. Please consult Plexicoat
America for additional information on the use of the PLEXIDECK Bridge Overlay System for lower
temperature projects.

5.2 Primer
Consumption of PLEXIDECK Primer is based on a coverage rate of 100 ft2 /gal at approximately
12 –15 mils. Actual consumption rate and resulting thickness may vary slightly depending on
substrate porosity and profile.

5.2.1 Powder Hardener

Plexicoat America, LLC • 1708 Whitehead Road, Suite 102B • Baltimore, MD 21207 PlexiDeck Bridge Deck Overlay System Instal ation Guide
5.3 Flexible Bodycoat
The Flexible Bodycoat Mix consists of PLEXIDECK Flexible Bodycoat Filler Component,
PLEXIDECK Flexible Bodycoat Resin Component and Powder Hardener.
Standard units are 30 lb PLEXIDECK Flexible Bodycoat Filler Component and 1.5 gal of
PLEXIDECK Flexible Bodycoat Liquid Component. Estimates are based on this formula with an
application thickness of 3/16". This will achieve a coverage rate of approximately 20 sq.ft. per
unit. Coverage rate may vary depending on the concrete profile.
5.3.1 Powder Hardener


5.4 Wearing Course Aggregate
Recommended aggregates include 6 x 10 basalt, emery or the like. Choice of aggregate varies
with local supply, DOT preference, etc. Final choice must be approved by Plexicoat America prior
to use.
5.5 Sealcoat
Consumption of PLEXIDECK Sealcoat to lock down the wearing course aggregate is based on a
coverage rate of 80 sq ft /gal.
5.5.1 Powder Hardener
Plexicoat America, LLC • 1708 Whitehead Road, Suite 102B • Baltimore, MD 21207 PlexiDeck Bridge Deck Overlay System Instal ation Guide
6.0 SURFACE PREPARATION

6.1 General
The PLEXIDECK Bridge Overlay system requires a clean and dry substrate free of oils, grease,
wax, solvents, curing membranes and any other contaminants. Thorough surface preparation is
essential to ensure a long-lasting bond to the substrate.
The PLEXIDECK Bridge Overlay system is not intended for use over bituminous-based
substrates. All deck surfaces must be mechanically blast cleaned using a mobile steel shot
machine with dust recycling.
All surface and embedded accumulations of hardened concrete layers, laitance, trowel finishes
and other similar surface characteristics must be completely removed.
Substrates with existing coatings must be prepared to the same result as above using appropriate
equipment including grinders, scarifiers, shot blast machines or other suitably effective
equipment. Existing coatings, other than methacrylate, must be removed to avoid possible
bonding/ compatibility problems.
After preparation, traces or accumulation of spent abrasives, laitance, removed coatings and
other debris should be removed by compressed air. All cracks should be cleaned out in the same
manner.
Final substrate condition must be clean and dry. An optional application of PLEXIDECK Crack
Sealer may be considered at this stage of the operation. See Section 6.3.3.
Concrete substrates must be dry prior to application of PLEXIDECK Primer/Sealer. After rain, it is
required to thoroughly dry prepared areas before installation. Judgments can be improved with
the measurement of moisture content using hand-held devices.
PLEXIDECK Primer must be cured prior to the installation of the PLEXIDECK Flexible Bodycoat.
So-called wet-on-wet techniques are not allowed.

6.2 Bond Test

6.2.1 Patty Test
Plexicoat America recommends performing a bond test shortly after surface preparation begins
so the degree of preparation can be adjusted based on results. This simple procedure allows for
the analysis of proper substrate preparation and ensures a successful installation.
1. Mix 6 vol. oz. of Primer with dry quartz sand until an easily trowelable consistency is 2. Add 10% by volume Powder Hardener and mix well. 3. Apply to properly prepared substrate in palm size patties 1/8” to 1/4” thick at various 4. Wait one hour (68º F), make sure patties are firm, tack-free and cool to the touch. 5. Remove patty samples with hammer and chisel (30 to 45 degree angle) and examine 6. The sample should clearly show concrete with fractured aggregate attached to the entire Plexicoat America, LLC • 1708 Whitehead Road, Suite 102B • Baltimore, MD 21207 PlexiDeck Bridge Deck Overlay System Instal ation Guide
If only laitance, fines, or small amount of concrete is attached, or if interface between patty and
substrate is tacky, further substrate preparation is required.

6.2.2
Quantitative (Pull-off) Bond Test

An alternative to the qualitative test is the “Pipe Cap Pull-off Test” which evaluates the strength of
the bond and the soundness of the substrate. Suitable test methods are ACI 503R, Appendix A
and California Test 420, Parts II and III. In these tests, the pipe cap is bonded to the substrate
with the PLEXIDECK Primer/Sealer slurry described in the previous paragraph. The minimum
pull-off strength should be 250 psi, depending on the magnitude of thermal cycling and
mechanical loading to be expected.

6.3 Concrete Repairs

6.3.1 Patching
Patching should be performed with PLEXIDECK Polymer Concrete, which is totally compatible
with the PLEXIDECK Bridge Overlay System. For details of the PLEXIDECK Polymer Concrete,
refer to the manufacturer’s appropriate specification and data sheet. The overlay can be applied
over cured PLEXIDECK Polymer Concrete patches. Repriming with PLEXIDECK Primer is
required prior to the application of the PLEXIDECK Flexible Bodycoat.

6.3.2 Grouting & Joint Nosings
Grouting to level depressions (such as wheel tracks, surface scaling, spalling, bolt anchors etc.)
may be performed with PLEXIDECK Polymer Concrete. This also applies to leading and trailing
edges of bridge decks, which should be cut back approximately 2" to 3" x •••" depth and short-
filled with PLEXIDECK Polymer Concrete to serve as a key for the Flexible Bodycoat.
PLEXIDECK Polymer concrete must be reprimed before accepting the PLEXIDECK Flexible
Bodycoat.

6.3.3 Surface Cracking
Static surface cracks, hairline to 1/8”, can be treated with PLEXIDECK Crack Sealer. This is a low
viscosity low surface tension methacrylate resin designed to penetrate, by means of gravity,
cracks on concrete bridge decks. The product is compatible with all PLEXIDECK systems and is
strongly recommended, where required, as an integral part of the overlay system. For details on
PLEXIDECK Crack Sealer, refer to the Plexicoat America specification and data sheet.

6.3.4 Dynamic Cracking
The PLEXIDECK Bridge Overlay system is not designed to bridge moving cracks. Such
conditions require treatment with other products.

7.0 PRIMING
Mix PLEXIDECK Primer and Powder Hardener as directed. Mix enough material for a 5 to 10
minute application. Immediately pour wet (uncured) primer onto concrete surface and distribute
with heavy nap, solvent-grade rollers at the rate of approximately 100 sq ft /gal, leaving a uniform
glaze on the surface. Avoid puddling of the primer. Reprime any areas indicating high surface
absorption of the primer. Allow to cure until tack-free, approximately 1 hour. A 20-30 mesh dry
Plexicoat America, LLC • 1708 Whitehead Road, Suite 102B • Baltimore, MD 21207 PlexiDeck Bridge Deck Overlay System Instal ation Guide silica sand can be used for a broadcast at a rate of up to 4 lb/100 sq ft especially if the deck is
sloped or if it is anticipated to open the cured, primed deck to traffic.

8.0 FLEXIBLE BODYCOAT

8.1 General
Flexible Bodycoat can be mixed in 5 gal pails with a mixing blade or in concrete drum mixers.
Measure out no more than 1.5 gal of PLEXIDECK Flexible Bodycoat Resin Component per 30 lb.
(one bag) of PLEXIDECK Flexible Bodycoat Filler Component.
Add PLEXIDECK Flexible Bodycoat Resin Component to container followed by Powder Hardener
and mix thoroughly for 30 - 60 seconds. Add PLEXIDECK Flexible Bodycoat Filler Component
and repeat, mixing to obtain a slurry consistency. Apply the slurry immediately after mixing by
pouring directly onto the primed and cured deck surface.
Distribute by means of steel gauge rake to desired thickness, normally 3/16”, at the rate of
approximately 20 sq ft per batch.

9.0 WEARING COURSE AGGREGATE
Broadcast to rejection the specified wearing course aggregate into the fresh, uncured
PLEXIDECK Flexible Bodycoat. Aggregate should be thrown into the air and allowed to "rain"
down into slurry to avoid rippling. Allow to cure approximately one hour. Remove excess
aggregate with brooms, power-sweepers or ride-on parking lot sweepers that collect and recycle
aggregates.  
 
10.0 SEALCOAT
PLEXIDECK Sealcoat is applied to the freshly swept wearing course using heavy nap (3/4")
rollers at a rate of 80 sq ft /gal. The Sealcoat should not be allowed to puddle and is meant simply
to lock down the aggregate rather than act as an integral film.

11.0 STORAGE
All products should be stored out of direct sunlight, preferably indoor in a cool, dry location.
Maximum temperature should not exceed 86° F. Under these conditions, minimum product shelf
life is six months from date of delivery.

12.0 SAFETY
All components of PLEXIDECK Bridge Overlay system in their uncured state present certain
hazards. PLEXIDECK Primer, PLEXIDECK Flexible Bodycoat Resin Component, and
PLEXIDECK Sealcoat are flammable liquids. Hardeners are organic peroxides. In all cases,
MSDS must be read and understood prior to handling these materials.

12.1 Resin Safety
One of the primary components of PLEXIDECK Primer, PLEXIDECK Flexible Bodycoat Resin
Component, and PLEXIDECK Sealcoat is methyl methacrylate (MMA). Other monomers used as
modifiers include n-butyl acrylate (BA) and 2-ethyl hexyl acrylate (EHA). MMA is used in a wide
variety of applications including safety glass (Plexiglass), automobile lenses, dental adhesives
and medical implants.
Plexicoat America, LLC • 1708 Whitehead Road, Suite 102B • Baltimore, MD 21207 PlexiDeck Bridge Deck Overlay System Instal ation Guide MMA, BA and EHA can be irritants to certain individuals. Standard precautions regarding protective clothing must be followed. Any sources of ignition including open flames, cigarettes, etc. must not be allowed in the area where PLEXIDECK products are used. To provide perspective on the safe handling of PLEXIDECK products, here is a summary of typical safety data for acrylic monomers in comparison with monomers and solvents used in other patching systems. Unleaded gasoline and typical clean-up solvents are included.
Sources:
Sax, N., Dangerous Properties of Industrial Materials, Van Nostrand Reinhold, New York, 1979
Perry, R. et. al. Eds., Chemical Engineers’ Handbook, 5 th edition, McGraw-Hill, New York, 1973
Amerada Hess Corporation, Material Safety Data Sheet, Gasoline, Regular, Unleaded, No. 0323, Amerada Hess, 1997
Matheson Tri-Gas MSDS Online, www.mathesongas.com/msds, 2000
OSHA, Occupational Health and Safety Guideline for Ethyl Acetate,
www.osha-slc.gov/SLTC/healthguidelines/ethylacetate/recognition.html, 2000
National Occupational Health and Safety Commission, Exposure Standards - n-Butyl Acrylate,
www.worksafe.gov.au/databases/exp/az/nButyl_acrylate.htm, 2000

Volatility - Vapor pressure is a relative measure of volatility. The vapor pressures of MMA and
other acrylic monomers used in PLEXIDECK are low in relative terms and less subject to
evaporation. In comparison, note the extremely high values for acetone and especially unleaded
gasoline, a product used by many on a daily basis.

Odor - Odor threshold varies and is dependent upon chemical structure rather than vapor
pressure. Esters, especially acrylates and methacrylates, have distinct, sweet odors and
extremely low odor thresholds, making them very easy to detect. As seen when comparing other
properties, odor does not necessarily correspond to safety hazard.

Flammability- Flash point is the temperature at which the vapor over a liquid in a container can
be ignited when exposed to an ignition source. A liquid having a flash point below 141° F is
classified as a “Flammable Liquid” under 49 CFR 173.120. While MMA specifically and
PLEXIDECK liquids in general are flammable, their flash point is considerably higher than many
of the flammable liquids typically found in other patching systems or common solvents.

Exposure - The Threshold Limit Value (TLV) is a figure reported by the American Conference of
Governmental Industrial Hygienists (ACGIH) and represents the maximum allowable exposure
concentration of a substance in air over an eight-hour period. The TLV of 100 ppm for MMA is
Plexicoat America, LLC • 1708 Whitehead Road, Suite 102B • Baltimore, MD 21207 PlexiDeck Bridge Deck Overlay System Instal ation Guide extremely difficult to reach in a manufacturing environment or outdoors during application of thin
polymer overlays. In fact, the low odor threshold for MMA functions as an effective safety
indicator to limit excessive exposure.

Explosive Limits - The lower and upper explosive limits (LEL and UEL, respectively) represent
the range of concentration in air in which a chemical may explode when exposed to an ignition
source, analogous to gasoline in a carburetor. The values for MMA are notably higher than most
of the other chemicals listed. An MMA concentration of 21,000 ppm would not be a tolerable
environment.
In summary, while PLEXIDECK liquids possess certain safety hazards, the degree of these
hazards is quite manageable when compared to everyday chemicals and those found in other
patching systems.

12.2 Peroxide Safety
BPO is the only organic peroxide currently specified for PLEXIDECK products. Peroxides are
reactive materials and unstable by nature; this is what makes them desirable as initiators for resin
polymerization. Peroxides must be handled carefully regarding contamination and temperature,
both of which can cause premature decomposition. BPO products such as Powder Hardener are
50% mixtures on inert carriers, are safe to handle and are not corrosive in comparison with MEKP
products. As with any organic peroxide, BPO must be isolated from resins, accelerators, rust and
contaminants of any type. Non-sparking tools must be used for dosing Powder Hardener. Product
must not be transferred back into original containers. Equally, contamination of PLEXIDECK
liquids with Powder Hardener will result in premature polymerization and excessive heat
generation.
The recommended storage temperature for Powder Hardener is 77° F. Product quality is ensured
when material is kept below this temperature. The emergency temperature range is 113º to
122°F. Benzoyl Peroxide reaching this temperature must be moved immediately to cooler
conditions. The self-accelerating decomposition temperature (SADT) is 122º to 131° F. Benzoyl
Peroxide reaching this  temperature is subject to violent decomposition that cannot be reversed by
cooling. Under no circumstances should Powder Hardener be allowed to reach the SADT.
All safety temperatures are lowered when Powder Hardener comes into contact with
contaminants. Conversely, once Powder Hardener is added to PLEXIDECK Primer/Sealer, the
temperature restrictions are relaxed due to dilution effects.

12.3 Filler Safety
PLEXIDECK Flexible Bodycoat Filler Component contains silica sands and fine fillers. Silica dust
causes eye, nose and throat irritation.
Long term exposure to excessive concentrations of dust from products containing crystalline silica
may cause delayed (chronic) lung damage (silicosis). Acute or rapidly developing silicosis may
occur in a short period of time in heavy exposure in certain occupations.
Although silica sands are commonly encountered on beaches and vacation spots, the handling of
silica in an industrial environment requires certain basic safety practices. Standard precautions
regarding protective clothing and good personal hygiene must be followed.
Plexicoat America, LLC • 1708 Whitehead Road, Suite 102B • Baltimore, MD 21207 PlexiDeck Bridge Deck Overlay System Instal ation Guide

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