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Beremend - 02/2010 Christophe Denayer

Milled limestone in concrete. Beremend - 02/2010 Christophe Denayer. 1. Calcium Carbonate Fines (CCF). Milled limestone is CCF if : Minimum 95% of CaCO 3 (calcite, no chalk) Minimum 70% is passing sieve of 63µm Minimum 300 m²/kg Specific Surface Blaine . CCF will have : A filler-effect

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Beremend - 02/2010 Christophe Denayer

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  1. Milled limestone in concrete Beremend - 02/2010 Christophe Denayer

  2. 1. Calcium Carbonate Fines (CCF) • Milled limestone is CCF if : • Minimum 95% of CaCO3 (calcite, no chalk) • Minimum 70% is passing sieve of 63µm • Minimum 300 m²/kg Specific Surface Blaine • CCF will have : • A filler-effect • Chemical active as accelerator

  3. PREMIACAL® • Calcite is a chemical mineral composed out of natural calcium carbonate (CaCO3) and which is cristallised in a rhomboedric system.

  4. CCF has a filler-effect Cement & CCF 3 Cement 3 CCF 2 2 1 1 Cement without limestone Bosiljkov, Cem Concr Res 33 (2003) 1279-1286

  5. CCF influences the initial and final setting of cement Cement with limestone filler Final set Initial set Hawkins et al, PCA report (2003) • Initial and final set are reduced. • CCF is an activator of the hydration

  6. Rate of heat release of the pastes • The rate of heat release in a mixture with CCF, is influenced during the first 10 hours.

  7. What happens chemically during cement hydration ? C3A C-S-H C3A

  8. 2. CCF for all types of concrete. SCC SCC-precast Ready-mix concrete Semi-dry concrete PILLAR & BEAMS Ready Mix Concrete PAVING BLOCKS STAIRS

  9. 3. semi-dry concrete • Cement is acting as a « filler ». Replacement of 10 to 35% of cement immediate after some H after some D cement water hydrates + free CaO setting of cement network of cristals cement • The most important targets for us in the concrete market are the producers of : HOLLOWCORE FLOOR SLABS ROOF TILES PIPES PAVING BLOCKS

  10. Example : mix-design for paving blocks • Conclusion : • Substitution of 51 kg of cement (261/50 -> approx. 20%) result in costsavings of 600 HUF/m³ • Maximum is 30 to 35% of cementreplacing -> 1200 HUF/m³

  11. Architectural reasons : less efflorescence & brighter • Less risk on efflorescence, because of lower content of cement in mix-design without CCF with CCF CEM I CCF

  12. What in case of sulfate environment ? • Respect miminum content of cement of EN 206 (XS-classes, …) • Additional fines needed (=cement)? Replace cementwith CCF

  13. 4. Ready-mix concrete Ready Mix Concrete STAIRS Concrete screed CEM I CCF

  14. French method : k-value = 0,25 (EN 206)

  15. 5. Self compacting concrete (SCC) • Need for fillers in SCC • MLS disposes a constant water-absorption, colour, … SCC

  16. Mix design of Okamura & Ouchi, corrected by NL SCC mix-design in 9 steps : • volume of air • volume of coarse aggregates • volume of fine aggregates • volume of paste • ratio w/p • testing on mortar bars • testing on concrete • calculation • controlling

  17. Vair -> V coarse aggr -> Vfine aggr -> V paste • Assume : Vair = 2% or 0,020 m³ -> ➊ • Assume : 50% of rest-volume is used by coarse aggregates at their best stacked pile • V coarse aggr = 0,5.(1-Vair).ρb / ρa(in m³) -> ➋ • ρa = 2650 kg/m³ (specific weight of aggregates) • ρb = 1670 kg/m³ (best stacked weight of aggregates) • Remark : if 45%, use 0,45 in formula • Assume : V fine aggr = 0,45 (1 - V coarse aggr - Vair) • We are reducing the quantity of fine aggregates to garantee that the influence of the fluidity of the paste will also be applicable on the mortar. [Assume 0,45 – could also be 0,40] • V paste = 1 - V coarse aggr – Vfine aggr – Vair

  18. How to determine beta P of a powder bp • Cement -> 0,9 till 1,4 • Milled limestone -> 0,8

  19. w/p-ratio • Water-powder ratio : • Paste = powder + water • Powder = cement + addition • βpcement = 1,2 (CEM I 52,5 R) • βpaddition = 0,8 (milled limestone) • Assume relation cement/addition: 60/40 in volume • βp cement+addition = (0,6 x 1,2)+ (0,4 x 0,8) = 1,04 • Water : w/c-ratio : (1,04 x 1,0)/(0,6 x 3,15) = 0,55 • Correction-factor for waterdemand of powder : • CWm(between 0,7 and 1,0) -> assume 0,85 (not definitif) • w/p-ratio = Vw/Vp = CWm. βp cement+addition = 0,884 -> ➎ w/c-ratio without flow 1,2 liter water is needed for 1 liter of cement : So 1,2 lw / 1,0 lc = (1,2x1,0) / (1,0x3,15) = 0,38 1,04 liter water is needed for 1 liter of C+A : So 1,04 lw / 0,6 lc = (1,04x1,0) / (0,6x3,15) = 0,55 to reduce the risk for segregation

  20. Mortar mix-design (1) • Mortar consist of • Cement • Addition • Sand • Water • Admixtures • No coarse aggregates • Define 1500 ml of mortar : • Assume : 45% or 675 ml = absolute volume of sand • So, 55% or 825 ml = paste

  21. Mortar mix-design (2) We know fromearlier : • Beta p(C+A) = 1,04 • CWm = 0,85 • Vw/Vp = CWm. βp cement+addition = 0,884 Assume : • 45 % of mortar = sand -> 1500 ml x 0,45 = 675 ml • Ratio (Cement/Addition) = 60/40 Solution : • Vpaste = 1500 – 675 = 825 ml • Vw / Vp = Beta p(C+A) x CWm = 1,04 x 0,85 = 0,884 • Vp = Vpaste /(1 + Vw / Vp) = 825 / (1+0,884) = 438 ml • Vcement = 0,6 x 438 = 263 ml • Vaddition = 0,4 x 438 = 175 ml • Vw = Vpaste – Vp = 387 ml • We are looking for a just combination between • watercontent (Vw / Vp) • admixtures (%) % of admixtures [on powder content] s Mortar flow test [mm] Mortar funnel test [s]

  22. Mortar mix-design (3) • Not OK, correct with • Raising admixtures : flow (mm) will raise (a) • Raising CWm : more water in mixture, less viscosity, less time (s) for empty the funnel. (b) • Not OK, correct with sand-ratio : • Raising sand% : lower flow (mm) and higher time (s) • Other : • Change admixtures • Change cement/addition-ratio • Change coarse aggregates volume • 4. Conclusion : • we know CWm –% admixtures – Vw – Vc- Va -Vfine aggr [mm] – mortar flow test OK b a 7 s 11s [s] – mortar funnel test • Not OK, we can correct formula with • Reducing/raising admixtures • Correct CWm (reducing or raising) • Other sand % • Other changes % of admixtures

  23. Concrete mix-design (1) Coarse aggregates Mortar : 1. Fine aggregates 2. Paste = water + powder V-funnel • Vair = 2% or 0,020 m³ ->➊ • Assume : 50% of rest-volume is used by coarse aggregates at their best stacked pile • V coarse aggr = 0,5.(1-Vair).ρb / ρa(in m³) -> ➋ • ρa = 2650 kg/m³ (specific weight of aggregates) • ρb = 1670 kg/m³ (best stacked weight of aggregates) • Remark : if 45%, use 0,45 in formula Abrams cone

  24. Concrete mix-design (2) Abrams cone • If not OK : • corrections with % admixt. and/or water (CWm) • Conclusion : • V paste = 1 - V coarse aggr – Vfine aggr➌– Vair -> ➍ • % admixtures • Final correction factor CWm Results in function of application : V-funnel

  25. Calculation & controling • % of admixtures is defined (after concrete tests) • CWm is now defined (after concrete tests) • V coarse aggr & Vfine aggr & Vair are also known : ➊ ➋ ➌ • V paste = 1 - V coarse aggr – Vfine aggr – Vair -> ➍ • Vpowder = V paste / (1+Vw/Vp) • with Vw/Vp = CWm. βp cement+addition • Vw = V paste - Vp • Powder = cement + addition and the ratio C/A is known -> we can count the quantity of each powder Do we respect EN 206 ? • w/c ratio ? • minimum content of cement for the environmental class

  26. What you need in each laboratory is … Cone of Abrams Cone of Haegermann V-funnel for mortar test V-funnel V-funnel for concrete test

  27. Other testmethods to characterize fresh SCC • U-box • L-box • J-Ring • Stability on sieve • Orimet J-ring U-box Stability on sieve Orimet L-box

  28. SCC - applications • PRECAST CONCRETE. Typical applications : WALLS STAIRS COLUMS - PILLARS BEAMS • READY-MIX CONCRETE . Ready Mix Concrete

  29. Ask assistance by your superplasticizer-supplier Do not forget : SCC is technically feasible due to the latest development of polycarboxylates • MAPEI • BASF : SP = glenium® • (before Degussa, before Masterbuilders) • SIKA : SP = viscocrete® • CHRYSO : SP = premia®

  30. 6. Carmeuse Europe supplies to 400 concrete plants • 370 concrete plants in W-Europe (France, Belgium, NL) • 30 concrete plants in Central Europe (CZ) : • HOLCIM CZ (ready-mix concrete : SCC, screed, architectural,..) • RIEDER BETON (SCC-pillar&beams) • DYWIDAG (SCC-pillar&beams) • ZPSV (SCC-pillar&beams) • Prefa Brno (paving blocks, pipes,…) • HU : first clients

  31. 7. Scientific Review of MLS in concrete

  32. Thank you

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