Secondary Containment for Concrete Structures, A Review

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The Need for Secondary Containment

EPA, local and state regulations

Liability and public relations issues

Protection of the environment

Reliable structural protection

ENVIRONMENTAL PROTECTION

Reliable Structural Protection

Protection of concrete from spills of acids and alkali

Protection from erosion in sluiceways and trenches

Protection from thermo cycling from steam cleaning

Waterproofing floor decks

What Is ”Effective Secondary Containment" ?

Crack bridging over both existing and newly developing cracks

Make concrete impermeable to chemical infiltration

Resistance to chemical attack for the duration of the spill without damage to the lining

Condition of the containment system after the spill is cleaned up

The Technology

Thermoset Polymer Systems Flexible Elastomers Combination SystemsSemi-Flexible ThermoplasticsElasti- Liner

Rigid Thermoset Polymers

Epoxies: Amine, NovolacPolyesters & Vinyl EstersUnreinforced/Reinforced

Rigid Thermoset Polymers

Monolithic when reinforced with fiberglass with no seams or joints

Sprayable systems using laminar flakes for reinforcement and permeation resistance

Epoxies in strong alkalines Polyesters in acidic environments

Vinyl Esters in acid to alkaline with solvent resistance.

Novolac Epoxy strong mineral acid, caustics and solvents

Resistance to weathering and ultraviolet light No crack bridging

Flexible Elastomers

Polyurethane PolyureaPolysulfides (Joint Sealants)

POLYURETHANE

Two part spray applied Moisture sensitiveLow permeation resistanceGood weatheringDiluted Acids, Alkali & Oils

POLYUREA

Rapid cure onlyMoisture insensitiveHigh temperature compared to Polyurethane

Poor weatheringSwells in oil and solventsHigh modulus (less elastic)

Polysulfides (Joint Sealants)

Techni-Plus Flex 3 from KCC Corrosion Control

Crack Sealant for low cost minimum containment

Poor UV StabilityGood in oils poor in acids

Combination Systems

Plate Glass over a Mattress

Concrete Substrate

Fiberglass OverlayElastomeric Basecoat

Rigid Chemical Resitant Topcoat

Flexible Thermoplastics

High Density Polyethylene (HDPE)

Polyvinyl. Chloride (PVC)OTHER

HDPE

Used over soil for Pond liners and liners for Landfills

Difficult to use when liners have pipe penetrations

Non adhered to concreteUV Problems

Polyvinyl. Chloride (PVC)

Non adhered to concrete: shop made “drop in liner”

Used for primary tank linersUseful for secondary

containment in small indoor applications

UV Problems

OTHER

HYPALONFEP -Fluorinated Ethylene

PropylenePVDF- Polyvinylidene

Elasti-Liner from KCC Corrosion Control

Elasti-Liner

Breakthrough in polymer chemistry Secondary containment of the most corrosive

chemicals used in industry today Excellent elongation and tensile properties Chemical resistance equal to or superior to the

rigid and thermoplastic polymers. Spray, roller, or squeegee applied 250% elongation but will resist immersion of

unlimited duration in aggressive aqueous chemistry

Vaaler Award Winner 1995 , 1997

Cracked Containment Lining Before:

Elasti - Liner Installed over Cracked Lining

Elasti - Liner Joint

Elasti - Liner Joint

Extruded version in 5” wide rubber like tape

Chemically adhered to new or old concrete, polymer or steel

Crack bridging of 250 mils for expansion joints, construction joints and or cracks in foundations

Resists immersion in aggressive aqueous chemistry

Testing Crack Bridging Systems

Test method which best duplicates actual conditions:

Demonstrates very slow movement of the lining from two distinct starting points

Lining is covering an existing crack and over an uncracked surface where a new crack is induced.

Comparison of Materials

PERFORMANCE RATINGS OF POLYMERS COMMONLY USED IN SECONDARY CONTAINMENT ON CONCRETE

Materials Tensile Crack Weathering Chemical

Elongation Bridging Resistance

Epoxies 1% - 8% poor good goodEpoxy Novola 1% - 5% poor good excellentVinyl Esters 1% - 3% poor good excellentPolyester 1% - 3% poor good goodPolysulfides 200% - 400%good poor poorPolyurethane 200% - 300%good good fairPolyurea 200% - 400% fair fair

goodFlex. Plastic 100% - 200% good fair goodElasti-Liner 250% excellent

excellent excellent

Comparative Costs

Rigid Unreinforced Coatings $3.00 - $8.00 per square foot

Rigid Reinforced Linings $8.00 - $12.00 per square foot

Rigid Reinforced over flexible basecoat $8.00 - $12.00 per square foot

Urethane/ Polyurea Unreinforced $3.00 - $6.00 per square foot

Sheet goods $4.00 - $17.00 per square foot Elasti-Liner $5.00 - $12.00 per square foot

Summary

An effective lining system must: Bridge moving cracks Resist chemical exposure for significant

duration without damage Pass an environmental inspection after a

spill is removed Lining systems that compromise any of

these principles will also compromise the owner's facility and legal responsibility