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ARC Commercial Water

ARC Commercial Water. The Need for Coatings in Commercial Water. Technical Reasons for Attack. Concrete. When freshly poured it is highly alkaline ( ≥ 12.5 pH) . Exposure to acids with pH below 6.5 will attack most cement based concretes and below 4 all types will be attacked.

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ARC Commercial Water

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  1. ARC Commercial Water The Need for Coatings in Commercial Water

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  6. Technical Reasons for Attack Concrete • When freshly poured it is highly alkaline (≥ 12.5 pH). • Exposure to acids with pH below 6.5 will attack most cement based concretes and below 4 all types will be attacked. • Acids can be naturally occurring or manmade. • Decayed organic matter as well as manufactured inorganic acids. • Acidic solutions react with calcium hydroxide dissolving it forming salts ( chlorides, sulfates and nitrates). 6

  7. Concrete attack • Normal household waste has a pH between 6-8 yet it contains bacteria, sulfates and organic materials which generate sulfides. • In presence of water sulfides convert to hydrogen sulfide gas. • Hydrogen sulfide gases contact moist surfaces of pipe where it is oxidized by bacteria into sulfuric acid Damaged Crown H2SO4 O2 O2 H2S S2 + 2H HS + H Slime/Sludge Layer 7

  8. The Need for Coatings in Commercial Water • Concrete as a material of construction is porous and, due to its alkaline nature, is reactive when exposed to acidic compounds. • Naturally occurring sulfur oxidizing bacteria (thiobaccilius) metabolizes condensed H2S gases from decaying organic matter and generates dilute sulfuric acid 8

  9. The Need for Coatings in Commercial Water • Passive oxide films on steel are attacked by dilute acids found in sewerage systems. • Flow assisted corrosion with additional entrained solids/grit increase removal of passive oxides 9

  10. Coatings Available • Vinyl Sheet Liners • Linabond • T-Lock • Spray applied coatings • Polyurea’s • Epoxy’s • Trowel Applied Coatings • Cementitious • Reinforced Epoxy’s 10

  11. Sheet Liners with Seams 11

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  13. Blistering Liners can experience blistering under mastic coat in crown re-building Projects (Low Adhesion) 13

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  15. Typical Failure of Mat Reinforced Liner 15

  16. Polyurea underfilm corrosion 16

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  18. Cementitious failure 18

  19. Common Causes for prematureFailures • Seem delaminations are most common cause for sheet liner failures • Pinholes cause most failures in spray applied coatings • Outgassing of concrete • Entrained air in product • Bug holes in surface • Cementitious coatings fail due to low chemical resistance, low bond strength and pin holes 19

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  22. ADDRESSING BUG HOLES WATER BLASTING DOES NOT ALWAYS OPEN BUG HOLE TYPICAL CONCRETE WALL COMMON BUG HOLE MANY COATINGS MANUFACTURERS SUGGEST COATING OVER UNEXPOSED BUG HOLES TRAPPED AIR ESCAPES THROUGH COATING CAUSING PIN HOLE REQUIRING PATCHING WITH THIS APPROACH IT IS VERY DIFFICULT TO FIND AND REPAIR ALL PIN HOLES RESULTING IN POSSIBLE CONCRETE EXPOSURE TO CORROSIVE GASES 23

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  25. Abrasive blasting opens up bug holes 26

  26. ADDRESSING BUG HOLES CONT’ ABRASIVE BLASTING EXPOSES HOLE TYPICAL CONCRETE WALL INSTALLATION OF REPAIR MATERIAL ASSURES NO TRAPPED AIR (SPARGE COAT) COMMON BUG HOLE APPLICATION OF CHESTERTON S1HB COMPLETES COATING PROCESS 27

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  30. Chesterton Ultimate Protection • Ultimate Protection is a combination system designed to provide the best of both worlds in substrate protection. • We utilize a High Build Quartz Reinforced Composite and a High Build Mineral Reinforced Spray composite • ..\..\Brochures\Coatings\Trowelables for concrete\Ultimate Protection.pdf 31

  31. TYPICAL BARSCREEN CHANNEL, JUNCTION BOX AND WET WELL LINING SYSTEM 797 PRIMER @ 7-10 MILS WITH S1HB APPLIED @ 80-125 MILS DFT CHESTERTON 797 PRIMER AND S1HB MATERIAL APPLIED KEY IN 791 FOR SMOOTH TRANSITION 12” WATERLINE CHESTERTON 797 PRIMER AND 791 COMPOSITE MATERIAL APPLIED 797 PRIMER @ 7-10 MILS 791 APPLIED @ 250 MILS DFT FOR HIGH ABRASION AND IMPACT ZONES

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  33. What makes a superior product and application? • Manufacture under vacuum with high shear equipment. • No entrained air in product reducing pinholes • Coupling agents used for reinforcement materials provides denser lower permeation characteristics (more reactive sites) • Proper application and preparation methods are key to long term success. No coating will succeed without proper installation. 34

  34. Writing Specifications • Specify only the best technologies for performance • Demand higher standards for specifications • PERFORMANCE BASED SPECIFICATIONS • ..\Condition Surveys\City of Laredo.doc • Proven application histories in severe environments • Extended warranties (real warranties) • Chesterton Warranty..\..\..\My Documents\Warranty draft.doc 35

  35. Manufacturer/Installer Requirements • Demand the latest and most effective technologies in coating systems. • Demand better performance from the installers by tightening installation specifications. • Write performance based coating specifications. • Require single source responsibility. • substrate repair, coating installation 36

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