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Some expert witnesses are confused by the terms "permeable" & "waterproof" as they relate to concrete.
Waterproof VS Permeability
Increased concrete densities provide for stronger structures, for which I am an advocate. However, increased densities ONLY REDUCE concrete's permeability, they DO NOT render it impermeable (waterproof).
Experts need to stop claiming that higher psi concrete's are WATERPROOF - THEY ARE NOT ! Yes, they ARE less permeable, but water will still weep through the concrete - just at a slower rate.
None of the following references (all in my personal library) state that higher density concretes are waterproof:
Building Code Requirements for Structural Concrete (ACI 318M-08)
Steel Reinforced Concrete Structures, Mohamed A. El-Reedy (2008)
Reinforced Concrete Designers Handbook, 10th Ed Reynold & Steedman
Engineering Concrete Mix Designs & Test Methods, Irving, 1999
Advanced Concrete Technology Vol. #1 Constituent Materials, Newman & Choo, 2003
Advanced Concrete Technology Vol. #3 Processes, Newman & Choo, 2003
Advanced Concrete Technology Vol. #4 Testing & Quality, Newman & Choo, 2003
ACI 201.2R-01 Guide to Durable Concrete
Reinforced Concrete Design Theory & Examples, Macginley, 2003
Masonry and Concrete for Residential Construction, Beall, 2004
ASTM Steel Handbook, 3rd Ed, Bringas, 2002
Reinforcement for Concrete — Materials & Applications, ACI Educational Bulletin #2, 2006
ACI 506R - Guide to Shotcrete
Other Standards REQUIRE additional protection
Though one may be comfortable with the low permeability of 9,000 psi concrete, other trade standards specify the use of waterproof membranes (e.g. TCNA, CTIOA). Ignoring these other standards is as egregious as shooting a 2,500 psi pool shell!
Both TCNA and CTIOA require additional waterproofing measures under tile in vessels, tubs, showers, etc. Until those standards are repealed or modified, one cannot simply chose to ignore them.
Special Protections
The mere use of high density concrete does not provide protection from hydrogen sulfide or chloride corrosion of the concrete.
Protection from these ravages of nature can only be provided with special mix designs, concretes, admixtures and/or waterproof membranes.
The currently accepted ACI permeability tests have inherent flaws. The chloride ion penetration test (ASTM C1202) does not measure how rapidly the ions penetrate the concrete. Nor does the test account for variations in hydrostatic pressures, a variable that increases the permeability as the hydrostatic pressures increase. This is why this test is only used to test mix designs in a laboratory.
Through proper mix design and compressive strengths, one can deliver a low value of chloride ion penetration. However, there is no test available that allows one to demonstrate the in place chloride ion resistance. This testing is beyond the scope of the current ACI 318, which is the controlling document of most Building Codes and the IBC.
Waterproofing is a required trade practice
WATERPROOFING is also required to protect concrete and it's steel reinforcement from sulfates, hydrogen sulfide and chloride degradation. To prevent water from permeating through concrete basements and subterranean structures, waterproofing is oftentimes applied to the soils prior to the placement of reinforcement or to the outside of subterranean concrete structure prior to back-filling.
Just because a swimming pool has water intentionally added to the interior of the structure, does that mean that we do not have a duty to protect the concrete from the permeation of water from BOTH sides of the structure?
Paolo Benedetti
Aquatic Artist, Watershape Consultant, Expert Witness
"Creating water as art."™
Aquatic Technology Pool and Spa
©www.aquatictechnology.com
Some expert witnesses are confused by the terms "permeable" & "waterproof" as they relate to concrete.
Waterproof VS Permeability
Increased concrete densities provide for stronger structures, for which I am an advocate. However, increased densities ONLY REDUCE concrete's permeability, they DO NOT render it impermeable (waterproof).
Experts need to stop claiming that higher psi concrete's are WATERPROOF - THEY ARE NOT ! Yes, they ARE less permeable, but water will still weep through the concrete - just at a slower rate.
None of the following references (all in my personal library) state that higher density concretes are waterproof:
Building Code Requirements for Structural Concrete (ACI 318M-08)
Steel Reinforced Concrete Structures, Mohamed A. El-Reedy (2008)
Reinforced Concrete Designers Handbook, 10th Ed Reynold & Steedman
Engineering Concrete Mix Designs & Test Methods, Irving, 1999
Advanced Concrete Technology Vol. #1 Constituent Materials, Newman & Choo, 2003
Advanced Concrete Technology Vol. #3 Processes, Newman & Choo, 2003
Advanced Concrete Technology Vol. #4 Testing & Quality, Newman & Choo, 2003
ACI 201.2R-01 Guide to Durable Concrete
Reinforced Concrete Design Theory & Examples, Macginley, 2003
Masonry and Concrete for Residential Construction, Beall, 2004
ASTM Steel Handbook, 3rd Ed, Bringas, 2002
Reinforcement for Concrete — Materials & Applications, ACI Educational Bulletin #2, 2006
ACI 506R - Guide to Shotcrete
Other Standards REQUIRE additional protection
Though one may be comfortable with the low permeability of 9,000 psi concrete, other trade standards specify the use of waterproof membranes (e.g. TCNA, CTIOA). Ignoring these other standards is as egregious as shooting a 2,500 psi pool shell!
Both TCNA and CTIOA require additional waterproofing measures under tile in vessels, tubs, showers, etc. Until those standards are repealed or modified, one cannot simply chose to ignore them.
Special Protections
The mere use of high density concrete does not provide protection from hydrogen sulfide or chloride corrosion of the concrete.
Protection from these ravages of nature can only be provided with special mix designs, concretes, admixtures and/or waterproof membranes.
The currently accepted ACI permeability tests have inherent flaws. The chloride ion penetration test (ASTM C1202) does not measure how rapidly the ions penetrate the concrete. Nor does the test account for variations in hydrostatic pressures, a variable that increases the permeability as the hydrostatic pressures increase. This is why this test is only used to test mix designs in a laboratory.
Through proper mix design and compressive strengths, one can deliver a low value of chloride ion penetration. However, there is no test available that allows one to demonstrate the in place chloride ion resistance. This testing is beyond the scope of the current ACI 318, which is the controlling document of most Building Codes and the IBC.
Waterproofing is a required trade practice
WATERPROOFING is also required to protect concrete and it's steel reinforcement from sulfates, hydrogen sulfide and chloride degradation. To prevent water from permeating through concrete basements and subterranean structures, waterproofing is oftentimes applied to the soils prior to the placement of reinforcement or to the outside of subterranean concrete structure prior to back-filling.
Just because a swimming pool has water intentionally added to the interior of the structure, does that mean that we do not have a duty to protect the concrete from the permeation of water from BOTH sides of the structure?
Paolo Benedetti
Aquatic Artist, Watershape Consultant, Expert Witness
"Creating water as art."™
Aquatic Technology Pool and Spa
©www.aquatictechnology.com
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