Anticipating C-S-H gel volume increase in High-Energy Mixing (HEM) process with Penetration Resistance test in hardening cement based mixture in conditions below -8 degrees Celsius

1. Anticipated C-S-H gel volume increase in High-Energy Mixing (HEM) process
“For C-S-H it is widely accepted that the nano scale structure controls many engineering properties such as the
elastic module, creep and drying shrinkage” (Hamlin M. Jennings, Jeffrey W. Bullard “From electrons to
infrastructure: Engineering concrete from the bottom up”, Cement and Concrete Research, 2011)
Technology of HEM (see invention US2013-0305963A1) is an effective way to increase and/or establish required
level of quantity of C-S-H gel starting from the regular volume which is created in conventional mixing technology.
HEM technology begins and ends at the first step of creation cement based materials, i.e. during the process of mixing.
The main idea of HEM is to provide most favorable conditions for absorption the mechanical energy by the mixture.
With increased energy absorption more water attracts by the cement particles and the process of cement hydration
develops dipper and faster with formation additional portion of nano structured C-S-H gel.
With this point of view it is necessary to evaluate effectiveness of different variants of HEM process in comparing
with conventional mixing.
According R.A. Olson at al. “Interpretation of the impedance spectroscopy of cement paste via computer
modeling”, (Journal of material science 30, 1995, page 5081) the process of cement hydration is continuing at the
temperature below 0o
C, where the freezing of bulk water in the macro pores ends at -8o
C because high ionic strength
of the pore solution.
The supersaturated solution filling C-S-H gel smaller capillary pores freeze from the temperature below -23o
C and
above -40o
C. Therefore the reactions of cement hydration are able to continue there at the range of temperature from
minus 8o
C to -23o
C where the solution said above doesn’t freeze.
The determination of the Penetration Resistance developing in setting and hardening of cement past or mortar is
the convenient method for determination the kinetics of cement hydration in order to compare different mixtures
placed in different conditions. At the range of temperature shown above increase of the Penetration Resistance will
give evidence about continuous cement hydrations in capillary pores of C-S-H gel and developing its nanostructure.
To compare the process of C-S-H gel formation in the mixtures activated with HEM and conventionally mixed author
contained samples of both mixes in freezing camera at temperature -15o
C during 96 hours with determination of the
Penetration Resistance after every 24 yours. The tests with the Penetration resistance determination were fulfilled after
thawing of frozen samples during approximately one hour with the increase of temperature of mixes from -15o
C to
+15o
C. See results Fig 1, 2.

2. Fig 1. Penetration Resistance development at temperature below -8o
C for cement-water mixture.
Conditions: W/C = 0.297, Superplasticizer SiKa 6100-1ml/kg of activated and control mix,
Time of activation 3.5 min,
Average speed N = 2464 rpm,
Average Absorbed Power = 407 wt/Kg, Efficiency coefficient = 0.63,
Average Re number = 161,
Average Power number = 1.48.
Increase of graph area (Fig 1) for activated mix in comparing with regular one is 96%. Thus the anticipated increase of
C-S-H gel volume is almost 2 times as a result of High-Energy Mixing.
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PenetratiionResistance,psi
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Penetration Resistance at -15oC
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3. Fig 2. Penetration Resistance development at temperature below -8o
C for cement-sand-water mixture.
Conditions: C/W/S = 1.0/0.376/2.0, Superplasticizer ADVA-190 4 ml/kg of activated mix, 1.8 ml/kg of control mix.
Time of activation 4 min,
Average speed N = 1695 rpm,
Average Absorbed Power = 132 wt/Kg, Efficiency coefficient = 0.39,
Average Re number = 141,
Average Power number = 0.73.
Increase of graph area (Fig 2) for activated mix in comparing with regular one is 213%. Thus the anticipated increase
of C-S-H gel volume as a result of High-Energy Mixing is more than 3 times.
CONCLUSION: The volume increase of nanostructured C-S-G gel is a main result of The High-Energy Mixing in
conditions of quasi laminar flow of the cement based mixtures when Re number less than 800 according the invention
US 2013-0305963A1.
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Penetration Resistance at -15oC
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