Dr. J. Juhart 1 11.03.2015 Rheo-Kolloquium Regensburg Tests der Wirkung von PCE-Fließmitteln auf Stoffe für Ressourcen-effizienten, nachhaltigen Beton Effect of PCE-Superplasticizers on Powders for Eco-Concrete Institute of Technology and Testing of Building Materials Institute of Applied Geosciences Laboratory for Particle Analysis (RCPE) Graz University of Technology
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Tests der Wirkung von PCE-Fließmitteln auf Stoffe für ... Ressourcen-effizienten, nachhaltigen Beton Effect of PCE-Superplasticizers on Powders for Eco-Concrete Institute of Technology
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Dr. J. Juhart 111.03.2015 Rheo-Kolloquium Regensburg
Tests der Wirkung von PCE-Fließmitteln auf Stoffe für Ressourcen-effizienten, nachhaltigen Beton
Effect of PCE-Superplasticizers on Powdersfor Eco-Concrete
Institute of Technology and Testing of Building Materials
Institute of Applied Geosciences
Laboratory for Particle Analysis (RCPE)Graz University of Technology
Dr. J. Juhart 211.03.2015 Rheo-Kolloquium Regensburg
Motivation Climate Protection and Sustainable Development
test‐profile (rate of shear history)pre‐shearing data aquisition
measurement points
Dr. J. Juhart 2111.03.2015 Rheo-Kolloquium Regensburg
0
2
4
6
8
10
0 50 100 150 200 250
torque
[mNm]
rotational frequency [1/min]
dolomite powder "eco"min. water demandSP_144 0,025%SP_144 0,15%
0
2
4
6
8
10
0 50 100 150 200 250
torque
[mNm]
rotational frequency [1/min]
CEM I 52,5 Rmin. water demandSP_144 0,025%SP_144 0,4%
Results Rheometer – flow curves
Yield value min. water demand M0,mwd~ const.for all water/powder mixes
SP saturation SP saturation
M0 yield value atmin. water demand
viscosityviscosity
M0 yield val. atmin. waterdemand
mwdMMMrel
,0
00.
Dr. J. Juhart 2211.03.2015 Rheo-Kolloquium Regensburg
0,0
0,2
0,4
0,6
0,8
1,0
1,2
0,00 0,25 0,50 0,75 1,00 1,25 1,50 1,75
rel. M0 [‐]
mPCE_solid/Vp [%]
SP 144‐HC
CEM I 52,5 Rlimestone eco 1dolomite ecodolomite microlimestone microquartz ecomicrosilica
0,0
0,2
0,4
0,6
0,8
1,0
1,2
0,00 0,25 0,50 0,75 1,00 1,25 1,50 1,75
rel. M0 [‐]
mPCE_solid/Vp [%]
SP 108‐LC
CEM I 52,5 Rlimestone eco 1dolomite microdolomite ecolimestone microquartz ecomicrosilica
Results Rheometer –yield stress (rel. M0) vs. SP-dosage
Dr. J. Juhart 2311.03.2015 Rheo-Kolloquium Regensburg
Results Rheometer – rel. M0 vs. rel. η
0,0
0,2
0,4
0,6
0,8
1,0
1,2
0,00 0,25 0,50 0,75 1,00 1,25 1,50 1,75
rel. M0 [‐]
mPCE_solid/Vp [%]
SP 108‐LC
CEM I 52,5 R
limestone eco 1
dolomite micro
dolomite eco
0,0
0,2
0,4
0,6
0,8
1,0
1,2
0,00 0,25 0,50 0,75 1,00 1,25 1,50 1,75
rel. η [‐]
mPCE_solid/Vp [%]
SP 108‐LC
CEM I 52,5 R
limestone eco 1
dolomite micro
dolomite eco
Dr. J. Juhart 2411.03.2015 Rheo-Kolloquium Regensburg
0
2
4
6
8
10
12
0 50 100 150 200 250
torque
[mNm]
rotational frequency [1/min]
microsilica
SP_108‐LC 0,05%
SP_144‐HC 0,05%
min. waterdemand
Influence of PCE-SP on Microsilica (d50~0,2µm)
+ SP
Dr. J. Juhart 2511.03.2015 Rheo-Kolloquium Regensburg
Summary and Conclusion
• investigations by spread flow test and Rheometer
• SP-demand of CEM I > SP-demand of most stone powderswith similar fineness to CEM I(differs for quartz-dolomite-limestone)
• viscosity of CEM I mixes > viscosity of most stone powder mixes of similar fineness
• „SP-demand“ ↗ with increasing fineness of powdersincrease of yield stress & agglomeration of PCE with very fine powders observed
• for stone-powders: only small differences between SP-HC and SP-LC
• spread flow over time:decrease for cement (SP-HC ) > decrease for stone powders(almost no decrease over time for stone powders with all SP)
• estimation of spread flow of powder-mixes is possible when knowing the SP-demand of single ingredients (by summing up the weighted spread flows)
• Outlook: testing of the effect of SP on powders in pore solution of cement-limes is recommended (pre-tests show a big influence of pH-value and ions in pore solution on the interaction of powders and pore solution)
Dr. J. Juhart 2611.03.2015 Rheo-Kolloquium Regensburg