Delivering Maintenance-Free Durability in Underground Infrastructure

Delivering Time-Proven, Design-Life,
Maintenance-Free Durability in
Underground Concrete Infrastructure
© Copyright Cementaid International Ltd.

 The function of underground structures is to
separate the proposed activities from the
underground elements, especially water.
 ALL concrete gets wet because it sucks in water
 Therefore, all concrete structures must be
‘waterproof’ in order to fulfil their function.

 Capillaries & air voids make up ~
6 - 10% of the volume of good
quality concrete
 Only two possible water transport
“mechanisms”
1) Hydrostatic pressure
 Test : “Permeability”
Measures rate of moisture movement
under pressure – “saturated flow”
e.g. Submerged concrete
2) Capillary absorption
 Test : “Absorption”
Measures rate of moisture movement by
capillary action – “Suction”
e.g. Air-exposed concrete
Note: Capillary Absorption operates with or
without an applied head of pressure.
 Which is the PRIMARY WATER
TRANSPORT mechanism?

 "Clearly ‘permeability’ is not a good measure
of resistance to chloride penetration.”
 “Capillary Absorption is the primary
mechanism by which water & chlorides
infiltrate concrete.”
 “The speed of capillary absorption is of
the order of 10¯6 m/s - a million times
faster than permeability.”
 “Up to 20 mm of quality concrete can be
penetrated in a few hours by this mechanism
on first contact with water containing
chlorides.”

O2
Absorbed
Water
Evaporated Water “DEW” Point
Corroding Reinforcing Steel
Chloride Build-up as water evaporates

SO, HOW IS THAT
‘WATERPROOFING’ WORKING
NOW?
Click on the image to
start/stop the video

 Recognise that even the best, normal concrete is
porous
 That absorption of water, porosity, is an
inherent deficiency of even the best reinforced
concrete as a structural material
 Look at the concept the iron industry uses, as
‘stainless steel’.
 Use time proven materials to deliver concrete
that will not absorb water or allow water to
enter it, even under pressure, for the design life
of the structure.

1. Chloride Attack on Embedded Metals
2. Sulphate Attack on Cement Paste
3. Acid Attack on Cement Paste and Embedded Metals
4. Delayed Ettringite Formation (DEF)
5. Alkali Attack on Reactive Aggregates (ASR)
6. Pure Water Attack on Cement Paste (snow melt, etc.)
7. Galvanic/Electrolytic Attack on Embedded Metals
8. Freeze / Thaw Attack on Cement Matrix
9. Surface Spalling due to Salt Crystallisation
10. Very High Temperature/Fire Destruction of Cement Matrix
11. Expansion/Contraction Cycling caused by Wetting/Drying
These are the mechanisms of corrosion / destruction, NOT the cause

 Barrier-Type Coatings, Membranes Surface Repellents,
etc.
 Epoxy/resin coated re-bars, and Concrete
 Galvanized Steel, Stainless Steel or other alloyed re-bars
 Cathodic Protection
 Chemical Cathodic Protection, Calcium Nitrites, etc.
 Low C3A, Sulphate Resisting Cements
 High Alumina Cements
 Very High Strength, High Cement Contents
 Exotic Mixes of Blended OPC, Low-Heat and SCM’s
 Expensive, Ultra-Low Reactivity Aggregates
 Very High Cover To Reinforcing Steel
 High Alkali Cements, Etc., etc.,
These do NOT treat the CAUSE of corrosion

In all of the eleven mechanisms of corrosion /
destruction of reinforced concrete, there are;
 6 Chemical Reactions. (1,2,3,4,5,6)
 1 Electrolytic Reaction. (7)
 4 Physical Actions (8,9,10,11)
But there is ONLY ONE COMPONENT in these
11 mechanisms that is common to
 ALL CORROSION / DESTRUCTION OF CONCRETE

Water…
Water is;
•A solvent
•An electrolyte
•A chemical reactant
•A medium in which chemical and electrolytic reactions take place
•A physical agent of volume change
•A carrier of reactive and reacted materials
THE PRESENCE OF WATER IS
THE CAUSE OF ALL CORROSION OF REINFORCED CONCRETE

1. Chloride Attack on Embedded Metals
2. Sulphate Attack on Cement Paste
3. Acid Attack on Cement Paste and Embedded Metals
4. Delayed Ettringite Formation (DEF)
5. Alkali Attack on Reactive Aggregates (ASR)
6. Pure Water Attack on Cement Paste (snow melt, etc.)
7. Galvanic/Electrolytic Attack on Embedded Metals
8. Freeze / Thaw Attack on Cement Matrix
9. Surface Spalling due to Salt Crystallisation
10. Very High Temperature/Fire Destruction of Cement Matrix
11. Expansion/Contraction Cycling caused by Wetting/Drying

Reverse the natural absorptiveness of normal concretes,
to STOP the two mechanisms of
1. pressure permeability
2.capillary absorption
Just as the modern metallurgist changes the properties of iron, by adding
proven additives like carbon, chrome, nickel, etc., to change the properties
of low tensile strength, rusting iron into steel, the modern concrete user
adds proven ingredients to his good quality concrete, to reverse its
inherent deficiency of POROSITY.
We use a HYDROPHOBIC PORE BLOCKING INGREDIENT, like the
Cementaid Everdure Caltite System.
This time-proven ingredient makes the pores, capillaries and micro-cracks,
water repellent and then, physically blocks them against water entering
under high pressures.

All Waterproof & Corrosion Proof concrete
must
1. Have an optimum minimum cement content of not
less than 335Kg/m3
2. Have a W/C ratio not exceeding 0.45
3. Contain a Hydrophobic, Pore Blocking
Ingredient (HPI) that will deliver water
absorption results of less than 1% from field
samples, when tested in accordance with BS1881
Part 122; 1983, the age at test shall be 7 days.
4. The HPI used must have an independently verified
record of successful application in the field, of not
less than 25 years.

Cracks DON’T matter, …
Because your HPI concrete is permanently,
inherently,
DRY!

Cracks in plain concrete create
dramatically larger surface areas
for water to be absorbed into the
matrix.
Worse. This oxygenated water is
very rapidly absorbed along the
porous steel /concrete interface,
delivering classic ‘cigar’ shaped
spalling.
Interior surfaces of any crack in Caltite
concrete are Hydrophobic and Pore
Blocked. Water cannot be absorbed
through any HPI concrete surface.
MOST IMPORTANTLY. No water can
be absorbed along the embedded
steel bars, because they are
embedded in HPI concrete that
cannot get wet.
PROOF © Copyright Cementaid International Ltd.

Demonstration of
CEMENTAID’s Everdure Caltite System
CRACKS DON’T MATTER
The Story;
During a Caltite basement wall pour, the steel reinforcement frame shifted during
casting and was half exposed on stripping. Regrettably, the fault was covered up
with a 40mm sand/cement render, rather than demolish and rebuild the section.
The problem was discovered 8 years later, when the salt water leaking from the
upper level room of the salt water pump house to the surface render, had caused
the partially exposed reinforcing steel to corrode so badly that it blew off the
render, to show the corroding steel protruding from sound Caltite concrete.

Ground Water
Analysis;
Chlorides:
53,000 mg per litre
Sulphates:
7,200 mg per litre
*Service temperatures up to 50°C (summer)
 Truly waterproof concrete
will remain durable even
under severe exposure
conditions ..

CALTITE concrete (CALTITE)
after 18 Years
BHP Water Pipeline - Port Pirie Salt Pan, SA
S. Aust. Govt. Engineering & Water Supply Dept. (1960 / 2002)

CALTITE concrete (“Caltite”)
after 40 Years
BHP Water Pipeline - Port Pirie Salt Pan, SA
S. Aust. Govt. Engineering & Water Supply Dept. (1960 / 2002)

 Comprehensive research
by VicRoads (AUS)
confirms maximum void
reduction (ASTM C642)
using HPI (Caltite), &
concludes…
 “This is a very efficient
material. (Caltite) has been
found to outperform both
conventional as well as SCM
concretes (silica fume, slag &
PFA) with far greater
reductions in VPV. “
 Caltite reduced permeable
voids by 1.5, 2, 3 and 6 times,
over silica fume, PFA, slag &
crystal-growth additive
respectively
0
5
10
15
20
25
30
CALTITE
Silica
Fume
PFA
ggbf
Slag
crystal-
growth
% REDUCTION IN
VOLUME OF PERMEABLE
VOIDS (VPV)
Australian State Government Research
VicRoads – Geopave, Victoria (1998)

 NSW RTA research
confirms maximum
REDUCTION in Water
Uptake (capillary action) is
provided by HPI
concrete (“Caltite” & “3CC”)
 “Densifying” (2)
(permeability reducing)
additives have only a
marginal effect on water
transport by capillary
action
%Reduction in Water Uptake
HPI 1 (“CALTITE”)92.3%
HPI 2 (“3CC”) 91.5%
Crystal-growth 12.5%
0
20
40
60
80
100
Everdure
Caltite
3CC
Crystal-
growth
% REDUCTION in
WATER UPTAKE
50 MPa concrete

demonstrates completely
effective protection against
water & chlorides is provided
by HPI concretes
(Caltite & 3CC)
Conclusion: “The HPI’s can
be used to protect
concrete against
moisture & chloride
ingress under conditions
of atmospheric
exposure.”
0
20
40
60
80
100
%Chloride
Reduction
at 20mm
Everdure
Caltite
3CC
Crystal-
growth
% REDUCTION in
CHLORIDE PENETRATION
50 MPa concrete
% REDUCTION in Chlorides
@ 20 mm depth
HPI 1 (“CALTITE”) 100.0 %
HPI 2 (“3CC”) 98.7 %
Crystal-growth 23.5 %

 “..The HPI
concretes (Caltite &
3CC)..lose more weight
during each drying
phase than was
absorbed in the
previous immersion
phase, with a
continual weight
reduction leading to
drier concrete.”
CONTROL
CALTITE

Conclusions..
“”..The (silicate-type)
additive showed little
difference to untreated
concrete, absorbing
and losing water freely
during each stage of
the test.”
CONTROL
crystal growth

demonstrates
completely effective
protection against
water & chlorides is
provided by HPI
concretes
(Caltite & 3CC)
 Conclusion: “The HPI’s
can be used to protect
concrete against
moisture & chloride
ingress under conditions
of atmospheric
exposure.”
76.42
62.05
3.15
99.7797.86
30.98
98.41 100
25.35
0
10
20
30
40
50
60
70
80
90
100
%
0 - 5mm 10-15mm 20-25mm
% REDUCTION in Chloride (CTI / RTA)
CALTITE 3CC CRYSTALGROWTH

This is a photo from the phone
camera of the National Sales
Manager Cementaid Singapore,
Mr. Gabriel Leung.
Taken Thursday, 26th May, 2001,
at about 6pm, it shows the view
down to 30 metres below water
table, where the first pour of the
new Everdure Caltite System
concrete basement slab is being
placed
This MRT station is constructed
using top down method.

 Specify, Design and Use, permanently DRY!
Everdure Caltite System concrete in your project
 www.cementaid.comcaltite2.htm
 Contact your nearest Cementaid operation at;
Or e-mail us directly, at;
 caltite@cementaid.com
Thank you for your attention and interest

Delivering Maintenance-Free Durability in Underground Infrastructure

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