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1 Leading Sponsors Supporting Sponsors Refreshments sponsored by Lunch sponsored by Program Sponsors

2 Sewer Collection and Wastewater Infrastructure Rehabilitation

3 Presented by Eric Zimmerman Project Development Manager NACE Certified Coating Inspector Level 3 Cert. # Years at Sherwin-Williams 14 years Protective & Marine Member of AWWA, NACE, & SSPC NACE Certified Coating Inspector

4 Overview The Corrosion Process The Rehabilitation Process Surface Preparation Stopping Inflow & Infiltration Structural Repair Mortars & Linings Protective Coatings & Linings Inspection

5 The Corrosion Process Old Age Freeze/Thaw Cycling Traffic Loading Microbial Induced Corrosion

6 The Corrosion Process Old Age The design life of most concrete structures or brick structures with cement mortar joints was 50 years. These structures, in many cases, have met or exceeded their design life.

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8 The Corrosion Process Freeze/Thaw Cycling Concrete always contains water within the capillary pore structure. When the retained water freezes it expands and over several cycles can spall concrete.

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10 The Corrosion Process Traffic Loading Constant traffic patterns of buried structures generates a large amount of deflection on the structure and can cause structures to shift or dissimilar materials to separate.

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12 The Corrosion Process Microbial Induced Corrosion This is the most common corrosion problem in sewer collection systems and wastewater infrastructure today. This is a 4 phase process that creates significant deterioration of the cement paste.

13 The Corrosion Process Microbial Induced Corrosion (MIC) PHASE I Sulfur reducing bacteria (SRB) break down sulfates in the waste stream and produce hydrogen sulfide (H 2 S) and carbon dioxide CO 2.

14 The Corrosion Process Microbial Induced Corrosion (MIC) PHASE II The acidic gases H 2 S and CO 2 act to reduce the ph of concrete from approximately 12 to as low as 9. Sulfur oxidizing bacteria (SOB) attach to the surface as sulfates are produced.

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16 The Corrosion Process Microbial Induced Corrosion (MIC) PHASE III The SOB s are known as Thiobacillus Thioxidans. They consume H 2 S and discharge sulfuric acid H 2 SO 4 The ph continues to drop and microbial growth accelerates creating more H 2 SO 4

17 The Corrosion Process Microbial Induced Corrosion (MIC) FINAL PHASE Acid attack of the concrete creates a layer of gypsum (calcium sulfate). As organisms reproduce additional acid is produced. Eventual structural failure

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19 The Rehabilitation Process Surface Preparation Stopping Inflow and Infiltration (I&I) Structural Repair Mortars and Linings Protective Coatings & Linings

20 Surface Preparation It is estimated that 85%+ coatings and linings failures are due to inadequate surface preparation. The process shall produce a surface that is free of contaminants, laitance, loosely adhering concrete, and dust, and shall provide a sound, uniform substrate suitable for the application of protective coatings or lining systems.

21 Surface Preparation Surface Preparation shall be conducted per SSPC-SP 13/NACE No. 6 Concrete Surface Preparation. The profile of the substrate shall be in accordance with the International Concrete Repair Institute (ICRI) Guideline 310.2R, Concrete Surface Profiles (CSP) 1-10.

22 Surface Preparation Mechanical Surface Preparation Methods Abrasive Blasting Preferred method for Brick or New, non-aged, concrete structures Pressurized Water Preferred method for aged concrete sturctures Impact Tools Used more for horizontal surfaces Power Tools Used more to remove surface imperfections caused during construction

23 Properly Prepared Concrete To Receive Protective Coatings & Linings

24 Surface Preparation How do I verify that I have removed all of the surface contaminants? Water Break Test How do I know if I have gotten the surface clean enough for the rehabilitation process? Substrate ph

25 Water Break Test

26 ph Test

27 Surface Preparation How aggressive should the profile of the substrate be? Protective Coatings & Linings Structural Repair and Rehabilitation

28 Surface Preparation

29 Surface Preparation What method of surface preparation should I use to best achieve the required CSP?

30 Surface Preparation Protective Coatings & Linings Structural Repair & Rehabilitation

31 Surface Preparation Protective Coatings & Linings Structural Repair & Rehabilitation

32 Stopping I&I

33 Stopping Inflow & Infiltration Why Stop I&I Prevents SSO s and CSO s Stops unnecessary treatment of ground water. Stops infiltration that is detrimental to a corrosion protection systems service life. Stops infiltration of Soils. Extends the life of the structure. Minimizes treatment plant cost. Stops sink holes from occurring

34 Stopping Inflow & Infiltration

35 Stopping Inflow & Infiltration Advantages of Chemical Grouts Longevity Lifespan is often greater than the concrete structures Repair accessibility Pressure injection Properties can be varied per application None to high elongation Field adjustable set times Light weight, Non-toxic, Non-biodegradable, Inert Final Product

36 Stopping Inflow & Infiltration Epoxy Grouts High compressive strength None to 25% elongation Moisture Tolerant Chemical Grouting High tensile strength None to over 250% elongation Installable in wet environments Epoxies are structural repair materials and are not for waterproofing

37 Stopping Inflow & Infiltration Hydraulic Cements Decent strength No elongation Surface seal only Plugs weaping water Normal longevity Chemical Grouts Very low strength None to over 250% Full depth penetration Can stop very high flows High longevity

38 Stopping Inflow & Infiltration Identifying a Grout Job Water Infiltration Dynamic joint or crack Joint between dissimilar materials High volume leak Non structural repair Long term fix required The catch all: When all other waterproofing methods have failed

39 Stopping Inflow & Infiltration Classifying Chemical Grouts Viscosity A measure of the resistance of a fluid which is being deformed by either shear stress or tensile stress. In everyday terms (and for fluids only), viscosity is thickness or internal friction. Measured in centipoises (cps) High: >1000 cps Moderate: cps Low: cps Very Low: cps Ultra Low: <250 cps Water = 1 cps

40 Stopping Inflow & Infiltration Classifying Chemical Grouts Hydrophobic: (water fearing) Uses very little water in its reaction. (5-7%) Requires a catalyst (allows for adjustment of reaction time). No post reaction swelling, has a closed chemical structure. Hydrophilic: (water loving) Can use up to 50% water in its reaction. No catalyst required. Has post reaction swell, retains an open chemical structure.

41 Stopping Inflow & Infiltration Single component: Can be pumped through a single component pump or a cartridge. Typically an airless paint sprayer such as a Graco 395 or equivalent, equipped with a grease gun. Plural component: (Uncommon) Requires a plural component pump.

42 Stopping Inflow & Infiltration Grout Placement Effective chemical grout placement requires getting the grout to the required location and holding it there long enough for it to react. Sounds silly but this key is often missed.

43 Stopping Inflow & Infiltration Drilling A hole is drilled to intersect the repair area and allow for the flow of grout throughout the repair area. Typically the hole is drilled at a 45 angle to the crack at a distance of half the structures thickness. Holes are spaced to allow for a continuous flow of grout from entry point to entry point. The less holes the better.

44 Stopping Inflow & Infiltration Crack Injection Method View of grout being injected into crack

45 Stopping Inflow & Infiltration Curtain Wall Grouting Manholes Leaking manhole to be grouted with grout wand

46 Stopping Inflow & Infiltration Curtain Wall Grouting Manholes Pressure injecting grout behind manhole wall

47 Stopping Inflow & Infiltration Curtain Wall Grouting Manholes Curtain grouting application completed. Leaks stopped.

48 Stopping Inflow & Infiltration Soak and Place Method Grout is mixed in a container and a suitable carrying material is used to hold the grout in place while it reacts. Also call the oakum soak-um method Suitable carrying materials: Oakum Open cell backer rod Cotton (rags and such)

49 Stopping Inflow & Infiltration Oakum Technique Oakum saturated with resin (grout)

50 Stopping Inflow & Infiltration Oakum Technique Resinsaturated Oakum being placed in the crack

51 Stopping Inflow & Infiltration Oakum Technique

52 Stopping Inflow & Infiltration Oakum Technique

53 Stopping Inflow & Infiltration Oakum Technique

54 Stopping Inflow & Infiltration Oakum Technique

55 Structural Repair and Rehabilitation

56 Structural Repairs Mortars and Linings What is the purpose of structural repair mortars and linings? Restoration Restore the structural integrity of the structure Restore the surface to a level plane or its original plane (depending on depth loss) Restore the structure to a suitable finish for accepting protective coatings and linings Protection Provide a thick barrier coating over the host substrate to aid in life cycle extension

57 Structural Repairs Mortars and Linings Existing sewer collection systems and wastewater infrastructure are constructed utilizing Portland cement concrete or mortar. This is the most common building material in the world and is susceptible to corrosion in these applications caused by sulfuric acid formation from bacterial growth (MIC).

58 Structural Repairs Mortars and Linings Why do you want to repair or rehabilitate with structural cementitious repair mortars? Restore areas of lost cross sections of substrate to a level or original plane Enhance the structural properties of the host substrate Lower the total project cost/return Time Provide a uniform surface for the application of protective coatings and linings

59 Structural Repairs Mortars and Linings These cementitious repair mortars are portland based cements with additives to reduce porosity and increase chemical resistance or calcium aluminate repair mortars.

60 Structural Repairs Mortars and Hydraulic Cements Linings USES Mainly, but not limited to, plugging holes, cracks and faults causing leaking and seepage through concrete floors, walls and junctions, general masonry, around inserts such as sleeves, pipes, etc. Suitable for any similar architectural or structural concrete application pits, mines, tunnels, reservoirs, manholes, miscellaneous grouting, etc.

61 Structural Repairs Mortars and Linings Microsilic Repair Mortars Description These are Portland based cements with graded silica sand aggregate and silica fume and may contain fiber reinforcement for improved physical performance properties. Commonly applied via hand trowel or spray applied and back troweled for substrate repairs from ½ to 2 in one lift. Microsilica Mortar provides an extremely dense matrix and will accept coatings at earlier ages than typical Portland cement repair products.

62 Structural Repairs Mortars and Linings CEMTEC Microsilica Repair Mortars Cemtec MSM CEMTEC Rapid Cure Vertical Grade CEMTEC Rapid Cure Vertical Grade (Manhole Raising)

63 Structural Repairs Mortars and Linings Calcium Aluminate Repair Mortars 2 generic classifications of calcium aluminate repair mortars. Both use calcium aluminate cement as the binder Pure Calcium Aluminate This is where the calcium aluminate is coarsely ground to create an agregate Calcium Aluminate This is where the aggregate is chemically inert silica sand

64 Structural Repairs Mortars and Linings Calcium Aluminate Repair Mortars The theory behind calcium aluminate repair mortars is that they maintain a higher ph at the surface that would inhibit the colonization of the bacteria that causes MIC.

65 Structural Repairs Mortars and Linings Calcium Aluminate Repair Mortars 2 generic classifications of calcium aluminate repair mortars. Pure Calcium Aluminate CEMTEC Hytec 100 Calcium Aluminate CEMTEC CAM

66 Structural Repairs Mortars and Linings Why would I select a microsilica over a calcium aluminate or vice versa? Selection is dependent and the end use and application Mild Service environments as a standalone liner use Microsilica Moderate service environments as a standalone liner use Calcium Aluminate Sever service environments with a protective coating/lining system use Microsilica Open top structures subject wind and varying atmopheirc conditions Only use Microsilica

67 Structural Repairs Mortars and Linings Limitations or Considerations Saturated Surface Dry (SSD) Substrates Proper Curing Finishing and Additional Surface Preparation

68 Waterbased Epoxy Cementitious Repair Mortar DuraPlate Reduces out gassing concerns associated with epoxy resins - Maybe applied to a surface saturated dry (SSD) substrate - Will hang vertically up to 1/4 thickness on a dry substrate with spray application and 3/16 with hand trowel application - Epoxy materials can be applied directly without the need for a primer - No secondary surface preparation

69 Protective Coatings and Linings

70 Protective Coatings and Linings Purpose To provide a chemical resistant isolation barrier for the concrete substrates in sewer collection system and wastewater treatment environments to prevent corrosion caused by corrosive gases and microbial induced corrosion. To prevent the same problem that caused the rehabilitation process

71 Protective Coatings and Linings Industry Evolution The industry has evolved drastically over the years. First issues in sewer manholes where addressed with cementitious liners and are still widely used today. First generation attempts with resinous coatings incorporated coal tar epoxy Second generation attempts with resinous coatings incorporated chemical resistant amine cured epoxy Still using second generation technology Regional introduction of polyurethane chemistry has taken place with success Regional introduction of polyurea chemistry has seen numerous challenges primarily with application.

72 Protective Coatings and Linings Available Technologies Epoxies Flake Filled Medium Builds Resinous Films High Build Resinous Films High Build Aggregate Filled Films High Build, High Strength, Resinous Films Polyurethanes Flexible Resinous Films

73 Protective Coatings and Linings Sherwin-Williams Products Epoxies SherGlass FF Reinforced Epoxy Dura-Plate 5900 (Formerly known as Cor-Cote SC Plus) Dura-Plate 5900 Epoxy Mortar (Formerly known as Cor- Cote SC Plus Epoxy Mortar) Dura-Plate 6100 Polyurethanes SherFlex

74 Protective Coatings and Linings Sher-Glass FF Reinforced Epoxy This is a 80% volume solids, treated glass flake, reinforced epoxy. Primarily used for misc. ductile iron and carbon steel piping components inside of structures Self Priming Film build of mils in a 2 coat application Applied via brush and roll or spray methods. Acceptable for application to SSD substrates

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76 Protective Coatings and Linings Dura-Plate 5900 (Formerly known as Cor-Cote SC Plus) This is a ultra high solids, high film build, epoxy lining. Used to protect concrete in sewer collection and wastewater environments Film build of mils in a single coat application No primer required on below grade, closed top structures Applied via brush and roll, single leg spray, and plural component spray application. Acceptable for application to a SSD substrate

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78 Protective Coatings and Linings Dura-Plate 5900 Epoxy Mortar(Formerly known as Cor-Cote SC Plus Epoxy Mortar) This is a ultra high solids, high film build, epoxy lining plus graded silica sand aggregate Used to protect concrete in sewer collection and wastewater environments Film build of mils in a single coat application No primer required on below grade, closed top structures Applied via hand trowel and spray/back trowel methods. Acceptable for application to a SSD substrate

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80 Protective Coatings and Linings Dura-Plate 6100 This is a ultra high solids, high film build, high strength, semi-structural epoxy lining. Used to protect concrete in sewer collection and wastewater environments Film build of mils in a single coat application No primer required on below grade, closed top structures Applied via heated plural component spray application. Acceptable for application to a SSD substrate

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82 Protective Coatings and Linings SherFlex Elastomeric Polyurethane This is a 100% solids, high film build, flexible, polyruethane lining. Used to protect concrete in sewer collection and wastewater environments Film build of mils in a single coat application Primer is required on concrete structures Applied via heated plural component spray application.

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85 Tools

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87 Questions?