Protect Your Assets: Water and Moisture Design Considerations in Concrete
Registered AIA Course, with SD & HSW “Hycrete, Inc.” is a Registered Provider with The American Institute of Architects Continuing Education Systems. Credit earned on completion of this program will be reported to CES Records for AIA members. Certificates of Completion for non-AIA members are available upon request. The program is registered with the AIA/CES for continuing professional education. As such, it does not include content that may be deemed or construed to be an approval or endorsement by the AIA of any material of construction or any method or manner of handling, using, distributing, or dealing in any material or product. Questions related to specific materials, methods, and services will be addressed at the conclusion of this presentation.
This course delivers Sustainable Design (SD) and Health, Safety, Welfare (HSW) learning units
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Learning Objectives • Understand how integral concrete technology can deliver sustainable benefit and protect your assets from moisture with: 1. Increased durability for structures 2. Reduced risk in both design & construction 3. Lower cost 4. Faster construction schedules
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Agenda 1. Concrete – General Properties
2.
Concrete – Water-Related Challenges and Consequences
3.
Concrete – Integral Technologies
4.
Applications/Examples
5.
How to Specify these Solutions
6.
Conclusion
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What is a Concrete Waterproofing Admixture?
1.
2.
3.
4.
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Concrete – The Fundamental Building Material • The world’s most widely used building material • 6 billion+ cubic yards produced annually • Very attractive properties – – – – – –
Inexpensive Readily available Good in compressive strength Versatile Durable Structural and decorative
• Used in commercial and infrastructure projects throughout the world CONFIDENTIAL
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What is Concrete Made of? • Three main ingredients – Aggregate (course and fine) – Cementitious (Portland, fly ash, slag) – Water (activates the cement to make it work) Makeup of a Cubic Yard by Weight
3%
Typical 5,000 psi mix:
5% Aggregate 17%
Cement Bound Water 76%
Free Water
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• • • • •
650 lbs cement 1,850 lbs course aggregate 1,100 lbs fine aggregate 22 gallons bound water 12 gallons free water Slide 7
Concrete – General Performance Properties Typical 5,000 psi Mix Property
Performance Range
Air or non-air
0-7%
Water/cement
0.42-0.48
Slump Absorption Set time
4-7” 3%-6% 4 hours @ 70F
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Agenda 1.
Concrete – General Properties
2. Concrete – Water-Related Challenges and Consequences 3.
Concrete – Integral Technologies
4.
Applications/Examples
5.
How to Specify these Solutions
6.
Conclusion
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Seven Things to Think About… …When Designing Concrete Structures Capillary Absorption
Durability & Maintenance
Leaks in Concrete
Floor Failure, Moisture & Mold
Environmental Considerations
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Aesthetics
Compatibility & Adhesion
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Design Issue 1: Capillary Absorption in Concrete • Average water absorption (5,000 psi mix): 3-6% • Water also brings in chlorides and other deleterious substances • Damp interiors and humidity • Freeze thaw damage Control
With Hydrophobic
Wicking
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Immersion Line
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Design Issue 2: Durability and Maintenance • Annual cost of corrosion to infrastructure: $22.6 billion • Leads to concrete spalling and freeze-thaw • Expensive and laborintensive maintenance
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Design Issue 3: Floor Failure, Moisture and Mold • Moisture vapor transmission through concrete leads to floor failures • Excess water in concrete affects flooring adhesion • Trapped moisture can cause mold growth
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Design Issue 4: Aesthetics • • • •
Efflorescence Staining Surface deterioration and spalling Color preservation
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Design Issue 5: Leaks in Concrete • Water enters through joints, penetrations & cracks • Leaks lead to building interior damage and expensive liability • Expensive repairs and delays
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Design Issue 6: Environmental Considerations with Concrete
• The production of Portland cement accounts for 9% of global CO2 emissions • Coatings and membranes, used to achieve concrete waterproofing objectives, contribute to landfill • Environmentally, it is important to: – Maximize concrete durability – Maximize concrete recyclability – Minimize added materials
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Design Issue 7: Compatibility and Adhesion • Adhesion problems related to concrete being too wet – Coatings, membranes and sealers
• Compatibility between admixtures – Affect on set time, workability, finishing, and other properties
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Agenda 1.
Concrete – General Properties
2.
Concrete – Water-Related Challenges and Consequences
3. Concrete – Integral Technologies 4.
Applications/Examples
5.
How to Specify these Solutions
6.
Conclusion
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Concrete – Integral Technologies
Permeability Reducers
Hydrophobic Admixtures
• Fly ash, slag, silica fume
• Liquid-based ammonia emulsion
• Treated silicates – “crystal growth” products
• Water-based admixture
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Comparing Permeability Reducers and Hydrophobics Permeability Reducers
Hydrophobic Admixtures
• Include liquid silicates or powder “crystal growth” • Form crystals that slow ingress • Densify concrete, reduce permeability, enhance compressive strength (e.g., Portland cement)
• Block capillaries • Form polymers that block ingress • Shut down capillaries (e.g., oil and water)
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Comparing Permeability Reducers and Hydrophobics
• Think of a beaver dam…sticks vs. mud
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Permeability Reducers – Densifying Concrete • Fly ash, slag, silica fume – – – –
Industrial by-products Powder Cementitious replacements Generally, will heal hairline cracks less than 0.4 mm
Fly ash – from electricity production using coal
Slag – from steel manufacture
Silica fume – from silicon manufacture
• Treated silicates – “crystal growth” – Powder or liquid – Hydrophilic products – absorb water – Product warranty, typically
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Hydrophobic Admixtures – Blocking Pores • Polymer Pore Blocking Agents – Physically block water absorption – hydrophobic – “Hydrophobic” = 0.5 mV
Hycrete DSS + CN
20
CN +SF+FA
10
CN+SF+slag
20
0
0
Weeks to Elevated Reading CONFIDENTIAL
CN+SF CN+SF+FA
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Modified ASTM G109: Weeks to Initial Activity Macrocell corrosion current activity in pre-cracked specimens (adaptation of ASTM G109) 120 Control
100 100
*Note: tests only lasted 100 weeks
CN 6% SF 15% FA
90
25%SLAG
8080 70
.5% Hycrete DSS
60
CN + SF
6050
CN +FA CN + Slag
40
Hycrete DSS + CN
4030 20
CN +SF+FA
10
CN+SF+slag
20
0
0
Weeks to Initial Activity CONFIDENTIAL
CN+SF CN+SF+FA
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Historical Hycrete Transport Properties Corrosion Inhibition by Hycrete Admixture Determination of chloride diffusion coefficient by ponding is superior to Rapid Chloride Permeability. Source: U. Mass DOT Testing
Chloride Diffusion Comparison between CN/SF/FA Combonation and Hycrete Concrete
Chloride Concentration (lbs/CY)
50 Surface to .5 Inches .5 to 1 Inch 1 to 1.5 Inches 1.5 to 2 Inches
40
30
20
10
0
Control
CN/SF/FA
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HYCRETE
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NJ Turnpike Results (5.5 yrs service) BSI-1881 Absorption Rate 1.60% 1.40%
% by Weight
1.20% 1.00%
1.34% Control (HPC)
0.80%
X1000 Hycrete (X1000)
0.60%
Hycrete: More than 4X better than control; full performance consistent with dosage.
0.40%
0.36%
0.20% 0.00% Control (HPC)
X1000 Hycrete (X1000)
Control vs Hycrete
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Hycrete Outperforms Latex-Modified Concrete Impact of Replacing Latex with Hycrete
Impact of Adding Hycrete Admixture 14.0
12.1
12.1
12.0
% Absorption in 24 hours
% Absorption in 24 hours
14.0
10.0 8.0 5.2
6.0 4.0 2.0
0.9
12.0 10.0
0.0 Control Mortar
Latex Additive
Latex + Hycrete Liquid
8.0 5.2
6.0 4.0
1.4
2.0 0.0 Control Mortar
Latex Additive
Mortar + Hycrete
Hycrete Adds Absorption and Corrosion Inhibition Benefits CONFIDENTIAL
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Hycrete Corrosion Performance - Summary
Mechanism Hycrete
Traditional
1. Keep water & ions out
Hycrete provides hydrophobic action, barriering diffusion
Densifiers: Silica Fume, Fly Ash, Crystal-growth Silicates (?questionable?)
2. Protect surface
Hycrete protects steel Barriers: ECR surfaces (water Inhibitors: Calcium Nitrite insoluble agent) (water soluble), OCI’s
3. Inhibit propagation
Hycrete slows rate of corrosion, post initiation
??
Hycrete provides multiple benefits, overall outperforms CONFIDENTIAL
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Value Delivered in Cementitious Materials • Enhances durability & freeze-thaw protection
• Reduces risk of water damage • Enhances building integrity • Reduces secondary efflorescence • Reduces staining • Contributes to LEED credits • Cradle-to-Cradle Certified
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Additional Benefits of Hycrete Technology • Performs under hydrostatic Concrete with Hycrete withstands hydrostatic pressure pressure • Crack-healing (ASTM C597) • Reduces vapor transmission Water pressure through concrete slab
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Risk Performance of Waterproofing Warranties Warranty Risk Comparison
• Typically a 10 Year Performance Based Warranty • Repairs performed by hydrophobic admixture company CONFIDENTIAL
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