MEASURING RHEOLOGICAL PROPERTIES OF FRESH MORTARS WITH CONCRETE RHEOMETERS Andraž Hočevar, Franci Kavčič, Igmat d.d. Violeta Bokan Bosiljkov, UL FGG

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1 MEASURING RHEOLOGICAL PROPERTIES OF FRESH MORTARS WITH CONCRETE RHEOMETERS Andraž Hočevar, Franci Kavčič, Igmat d.d. Violeta Bokan Bosiljkov, UL FGG University of Ljubljana Faculty of Civil and Geodetic Engineering

2 OUTLINE Motive Rheometers Test program Results Conclusions "Rheology of Building Materials", Regensburg, March, 1213,

3 MOTIVE Design process of concrete mixture can be time and raw materials consuming Concrete rheometers demand high volume of fresh concrete Tests on corresponding mortar Concrete equivalent mortar (CEM) method "Rheology of Building Materials", Regensburg, March, 1213,

4 MOTIVE Aim of this presentation is to show pluses and minuses of smaller measuring systems "Rheology of Building Materials", Regensburg, March, 1213,

5 RHEOMETERS ConTec Viscometer 5 Outer cylinder radius, R o = 100 mm Inner cylinder radius, R i = 85 mm Height of the cylinder is measured, (h 85 mm) "Rheology of Building Materials", Regensburg, March, 1213,

6 RHEOMETERS ConTec Viscometer 5 Outer cylinder radius, Ro = 100 mm Inner cylinder radius, Ri = 85 mm Height of the cylinder is measured, (h 85 mm) "Rheology of Building Materials", Regensburg, March, 1213,

7 RHEOMETERS ICAR Rheometer Outer cylinder radius, R o = 74 mm Inner cylinder radius, R i = 64 mm Height of the cylinder, h = 127 mm "Rheology of Building Materials", Regensburg, March, 1213,

8 RHEOMETERS ICAR Rheometer Outer cylinder radius, Ro = 74 mm Inner cylinder radius, Ri = 64 mm Height of the cylinder, h = 127 mm "Rheology of Building Materials", Regensburg, March, 1213,

9 TEST PROGRAM 26 mortars from ordinary concrete and 12 mortars from SCC mixtures Rheology and slump flow with equipment for flow table spread of mortar (SIST EN 10153:2001) Mixing procedure (5 min): Dry constituents 1 min Half of the water, 0.3 l of water with diluted liquid admixtures, rest of the water 1 min (while mixing) Mixing for another 3 min "Rheology of Building Materials", Regensburg, March, 1213,

10 TEST PROGRAM Measuring procedure: Enlarged version of standard mortar mixer Each mixture mixed once Average of 3 repetitions Remixed with flat rod before each measurement "Rheology of Building Materials", Regensburg, March, 1213,

11 TEST PROGRAM mixtures MORTARS FROM ORDINARY CONCRETE MR1 MR1A MR1B MR1C ML1 ML1A ML1B ML1C CEM I 42,5 R (kg) CEM II/AM (LLS) 42,5 R (kg) Aggregate 0/2 (kg) Water (kg) Superplasticizer (g) 5,6 11,2 16,8 5,6 11,2 16,8 MRA1A MRA1B MRA1C MG1A MG1B MG1C MV1A MV1B MV1C CEM I 42,5 R (kg) CEM II/AM (LLS) 42,5 R (kg) Aggregate 0/2 (kg) Water (kg) 3,588 3,588 3,588 3,098 3,262 3,428 Superplasticizer (g) Air entrainer (g) 2,24 3,36 2,80 Stabilizer (g) 8,40 11,20 MZ1A MZ1B MZ1C MM1A MM1B MM1C MT1A MT1B MT1C CEM I 42,5 R (kg) 4,48 3,36 2,24 5,32 5,04 5,46 5,04 4,48 5,32 Aggregate 0/2 (kg) Water (kg) Superplastizicer (g) 11,09 10,98 10,86 16,57 16,34 16,68 27,44 26,88 27,72 Tuff (g) Silica fume (g) GGBS (kg) 1,064 2,128 3,192 "Rheology of Building Materials", Regensburg, March, 1213,

12 TEST PROGRAM mixtures MORTARS FROM SCC MR1 MR2 MR3 MM1 MM2 MM3 MM4 CEM I 42,5 R (kg) Water (kg) 2,576 2,912 3,248 3,248 3,248 3,248 3,248 Aggregate 0/2 (kg) 14,052 13,470 12,886 13,326 13,778 14,232 14,836 Limestone filler (kg) 3,032 3,032 3,032 2,332 1,631 0,932 Superplasticizer (g) 60,42 60,42 60,42 55,52 50,62 45,72 39,20 Stabilizer powder (g) 11,20 14,00 16,80 19,60 MR4 MR4A MR4B MR4C MR4D CEM I 42,5 R (kg) Water (kg) 2,912 2,928 2,842 2,772 3,052 Aggregate 0/2 (kg) 13,405 13,405 13,405 13,405 13,405 Limestone filler (kg) 3,032 3,032 3,032 3,032 3,032 Superplasticizer polyphosponic (g) 99,26 99,26 99,26 99,26 99,26 "Rheology of Building Materials", Regensburg, March, 1213,

13 TEST PROGRAM Calculation of fundamental results Shear thickening behavior observed Bingham model on bottom 4 points 1 1 T 2 2 R Ro τ0 = i R 4πh ln o Ri µ = π h Ri Ro S S = slope T = intersection "Rheology of Building Materials", Regensburg, March, 1213,

14 RESULTS mix by mix Yield values ordinary mortars Bigger difference between rheometers at higher values Lines are parallel Repeatability is better for ConTec "Rheology of Building Materials", Regensburg, March, 1213,

15 RESULTS mix by mix Plastic viscosity ordinary mortars Lines are parallel, values almost identical "Rheology of Building Materials", Regensburg, March, 1213,

16 RESULTS mix by mix Yield value SCC mortars ICAR has zero values! "Rheology of Building Materials", Regensburg, March, 1213,

17 RESULTS mix by mix Plastic viscosity SCC mortars Lines are parallel, values almost identical "Rheology of Building Materials", Regensburg, March, 1213,

18 RESULTS correlation of rheometers Ordinary mortar "Rheology of Building Materials", Regensburg, March, 1213,

19 RESULTS correlation of rheometers SCC mortar As expected correlation for yield values is not OK "Rheology of Building Materials", Regensburg, March, 1213,

20 Additional analysis Analysis of variance: Change of mix design is statistically significant with 5% risk for both rheological parameters Except for ICAR rheometer measuring yield values of SCC mortar Post hoc tests (Duncan, Bonferroni) tell us that ICAR has bigger variances inside measurements "Rheology of Building Materials", Regensburg, March, 1213,

21 ZERO VALUES WHY? Is ICAR sensitive enough for measuring mortar? Shear rate? γ& Small container gives us bigger shear rate! Big vane in small container! Secondary flows? R + R 2 2 o i = 2 2 Ro Ri Ω [1] [1] Feys, D., Verhoeven, R., De Schutter, G Evaluation of time independent rheological models applicable to fresh selfcompacting concrete. Applied Rheology 17, 5, 56244: 110. "Rheology of Building Materials", Regensburg, March, 1213,

22 CONCLUSIONS In analysis we observe similar trends for both rheometers, except for yield values of SCC mortars. ICAR Rheometer is not suitable for measuring too liquid mortars. Further development is needed container and vane size should be decreased proportionally, change the shape of vane. Measurements should be done with appropriate shear rates. "Rheology of Building Materials", Regensburg, March, 1213,

23 THANK YOU FOR YOUR ATTENTION! University of Ljubljana Faculty of Civil and Geodetic Engineering