Successfully reported this slideshow.
We use your LinkedIn profile and activity data to personalize ads and to show you more relevant ads. You can change your ad preferences anytime.

Solutions to Address Osmosis and the Blistering of Liquid-Applied Waterproofing Membranes

20,790 views

Published on

Waterproofing membranes are widely used in the building industry as a barrier for water entry into a building enclosure. Over the past two decades, waterproofing system failure due to osmotic blistering has occurred in some protected membrane/inverted roofing assemblies. Not all waterproofing membrane assemblies are at risk for this process and the authors have developed a test protocol to establish the relative risk level of waterproofing membranes to osmosis. Using this protocol, the osmotic flow rate of SBS, hot rubberized asphalt, PMMA, EPDM, TPO, HDPE, polyurea, asphalt emulsion, asphalt-modified polyurethane, and various other 2-component cold applied membranes was measured to determine a threshold osmotic flow rate for low risk waterproofing membrane systems.

In this research, a wide range of osmotic flow rates were obtained for the various membrane types. Most asphalt-modified polyurethane membranes consistently exhibit osmotic flow rates significantly higher than the low-risk threshold of ~0.0 g/m²/day (typically 1.4 to over 20 g/m²/day) after data corrections, which results in osmotic blistering and premature membrane failures. Some polyurea and asphalt emulsion membranes have flow rates above 2.0 g/m²/day with unknown long-term performance, while most other membranes that were tested have flow rates around 0.0 g/m²/day after data corrections from control samples. To reduce the potential for osmotic blistering over concrete, it is recommended that waterproofing membranes used in inverted roofing assemblies should have an osmotic flow rate near 0.0 g/m²/day when tested using the methodology herein, an inverted wet cup vapour permeance less than that of the substrate (i.e. <0.1 US Perms on a concrete substrate), and minimal long-term water absorption.

Presented at the 15th Canadian Conference on Building Science and Technology.

Published in: Engineering
  • I think you need a perfect and 100% unique academic essays papers have a look once this site i hope you will get valuable papers, ⇒ www.WritePaper.info ⇐
       Reply 
    Are you sure you want to  Yes  No
    Your message goes here
  • I pasted a website that might be helpful to you: ⇒ www.HelpWriting.net ⇐ Good luck!
       Reply 
    Are you sure you want to  Yes  No
    Your message goes here
  • D0WNL0AD FULL ▶ ▶ ▶ ▶ http://1lite.top/Oft8S ◀ ◀ ◀ ◀
       Reply 
    Are you sure you want to  Yes  No
    Your message goes here
  • Be the first to like this

Solutions to Address Osmosis and the Blistering of Liquid-Applied Waterproofing Membranes

  1. 1. 1 Solutions to Address Osmosis: Blistering of Liquid Applied Waterproofing Membranes CCBST CONFERENCE, VANCOUVER BC NOVEMBER 8TH 2017 ELYSE HENDERSON, MSC; GRAHAM FINCH, MASC, P.ENG; BRIAN HUBBS, P.ENG PRESENTED BY ELYSE HENDERSON
  2. 2. 2  Background  Review of theories  Current research  Recommendations Agenda
  3. 3. 3 Background & History
  4. 4. 4 Review of Theories Pinholes in thin membrane Hydrostatic head from details Vapour diffusion from inside Diffusion & capillary from outside X X X X
  5. 5. 5 The Osmosis Mechanism  Requirements for osmosis to occur: 1. Semi-permeable membrane (impermeable to Total Dissolved Solids) 2. TDS concentration differential (higher osmotic flow rate with higher differential) Colligative Property
  6. 6. 6 TDS and Equivalent Osmotic Pressure Sample A Sample B Sample C Rain water pooled on membrane Total Dissolved Salts (TDS), mg/L 17,500 13,056 3,650 7 Osmotic Pressure, kPa 1,488 1,089 326 ~3  Extracted from water blisters under blistered membranes  TDS and equivalent osmotic pressure are elevated!
  7. 7. 7 Research Objectives 1) Determine the susceptibility of various waterproofing membrane types to osmotic blistering  Find true “zero” osmotic flow 2) Set test parameters and recommendations for low-risk membranes  e.g. osmotic flow rate, vapour permeance, absorption 3) Understand the aging effects of membranes in contact with liquid water for long periods of time  Changes in material properties (e.g. vapour permeance)  Degradation of the membrane
  8. 8. 8 Project Methodology  Osmotic flow rate testing  Method developed by RDH
  9. 9. 9 Project Methodology  Osmotic flow rate testing  Method developed by RDH  Vapour permeance testing per ASTM E-96  Wet cup  Inverted wet cup
  10. 10. 10 Project Methodology  Osmotic flow rate testing  Method developed by RDH  Vapour permeance testing per ASTM E-96  Wet cup  Inverted wet cup  Water absorption testing  Method adapted from ASTM D-570 for prolonged time  Water analysis  3rd-party analytical lab  Measure TDS concentrations and specific solutes
  11. 11. 11 Previous Osmosis Results 0 200 400 600 800 1000 1200 1400 1600 1800 2000 0 50 100 150 200 250 300 OsmoticFlow(g/m²) Time (days) Asphalt-modified polyurethane 1 Asphalt-modified polyurethane 2 Asphalt emulsion Polyurea membrane 2-Component membrane Low enough?
  12. 12. 12 Current Osmosis Results 0 200 400 600 800 1000 1200 1400 1600 1800 2000 0 50 100 150 200 250 300 OsmoticFlow(g/m²) Time (days) Asphalt-modified polyurethane Hot Rubber 1-ply Hot Rubber 2-ply SBS (1-ply) PMMA 1 PMMA 2 EPDM TPO HDPE
  13. 13. 13 TDS Dilution from Osmotic Flow 57600 57600 57100 53600 51000 52000 53000 54000 55000 56000 57000 58000 1.0 M NaCl 1.0 M NaCl (Hot Rubber) 1.0 M NaCl (PMMA) 1.0 M NaCl (Asph-Mod. Polyurethane) Concentration(mg/L)  Total Dissolved Solids (TDS) concentration after 8 months  TDS is diluted in the jar that took up most water, i.e. had the highest osmotic flow across membrane
  14. 14. 14 Osmosis Results Membrane Type (name or material) Membrane Thickness (mil) Osmotic Flow Rate (g/m²/day) Asphalt-modified polyurethane* 30 – 90 1.4 – 26.2 Asphalt emulsion 110 4.6 ±1.6 Polyurea 30 – 100 2.1 ±1.6 SBS (1-ply) 100 0.3 ±0.8 TPO 58 0.8 ±0.9 Hot rubberized asphalt (2-ply) 244 0.0 ±0.7 HDPE 52 0.0 ±0.7 PMMA 70 – 80 -0.2 ±0.8 2-Component cold-applied 40 – 90 -0.3 ±0.8 EPDM 47 -0.3 ±0.7 *Large range of membrane thicknesses and osmotic flow rates for asphalt- modified polyurethane samples (macroscopic variations in the samples)
  15. 15. 15 Colligative Property of Osmosis, Demonstrated 1.0 M 0.5 M 0.1 M 0.0 M 1.0 M 0.1 M 0.0 M 0 200 400 600 800 1000 1200 1400 1600 1800 0 25 50 75 100 125 150 175 200 225 OsmoticFlow(g/m²) Time (days) Asph.-Mod. Polyurethane, 1.0M Asph.-Mod. Polyurethane, 0.5M Asph.-Mod. Polyurethane, 0.1M Asph.-Mod. Polyurethane, 0.0M Hot Rubberized Asphalt, 1.0M Hot Rubberized Asphalt, 0.1M Hot Rubberized Asphalt, 0.0M Recall, osmosis requires semi- permeable membrane Flow rate depends on TDS concentration  Higher TDS = higher osmotic flow rate  But only for semi-permeable membranes
  16. 16. 16 How Does Vapour Permeance Affect Osmosis?  Osmotic flow rate is higher for high vapour permeance  How does aging affect membrane permeance? -5 0 5 10 15 20 25 30 0 100 200 300 400 500 600 OsmoticFlowRate(g/m²/day) Inverted Wet Cup Vapour Permeance (ng/Pa-s-m²) Aged Asphalt-modifed Polyurethane (blistering has occurred) Modified Polyurethane (non-asphalt) Polyurea New 2-component chemistries Hot rubberized asphalt PMMA 1-ply SBS
  17. 17. 17 Effects of Aging Membranes  Aged asphalt-modified polyurethane = higher permeance  Can prolonged water absorption help us understand aging? 0 5 10 15 20 25 30 0 100 200 300 400 500 600 OsmoticFlowRate(g/m²/day) Inverted Wet Cup Vapour Permeance (ng/Pa-s-m²) Aged Asphalt-modifed Polyurethane (blistering has occurred) New Asphalt-modified Polyurethane
  18. 18. 18 Water Absorption Results  Some membranes do not reach equilibrium  Unknown effects over longer time: 1 year? 5 years? 10 years?  Asphalt-modified polyurethane absorbs the most  Decease in mass points to membrane degradation -2% 0% 2% 4% 6% 8% 10% 12% 14% 16% 18% 0 20 40 60 80 100 120 140 160 180 200 220 240 260 ChangeinMass(%) Time (days) Asphalt-modified polyurethane Hot rubberized asphalt SBS (1-ply) PMMA 1 PMMA 2 EPDM TPO HDPE
  19. 19. 19 What is Coming Off the Membranes?  Total Organic Carbon (TOC) points to membrane degradation  Degrading membranes:  Change membrane properties (vapour permeance, rigidity, etc.)  Increase the TDS in the water blister › Self-propagation of osmosis in susceptible membranes 0 100 200 300 400 500 600 700 TOC Calcium Potassium Silicon Sulfur Concentration(mg/L) Real blister water 1.0 M NaCl (Hot Rubber) 1.0 M NaCl (PMMA) 1.0 M NaCl (Asph-Mod. Polyurethane)
  20. 20. 20 What are the Solutions?  Rules of thumb for selecting waterproofing membranes: 1. Measured osmotic flow rate near 0 g/m²/day (+/- 1) 2. Inverted wet cup vapour permeance lower than substrate 3. Minimal long-term water absorption or membrane degradation
  21. 21. 21 Questions CONTACT THE PRESENTER  ehenderson@rdh.com  1-604-873-1181

×