Physical and chemical characteristics of natural limestone fillers: mix properties and packing density

Transcription

1 3/3/ Physical and chemical characteristics of natural limestone fillers: mix properties and packing density Luc COURARD, Eric PIRARD and Huan HE Université de Liège, Belgium TC-SCM WORKSHOP, CYPRUS, 9-3 MARCH Outline Introduction Materials Conclusions

2 3/3/ Introduction Specific requirements for fresh SCC : high workability and good resistance to segregation. Amount of coarse aggregate reduced and replaced by fine material. In Belgium, local available materials = limestone fillers. Introduction Production process of limestone fillers Aggregate and lime production industry (quarrying operations)

3 3/3/ Introduction Production process of limestone fillers Ornamental stones industry (sawing operations) Materials Ordinary Portland Cement (PC) CEM I 4,5 R HES Six limestone fillers collected in Belgium (F to F6) Limestone filler reference F F F3 F4 F5 F6 Dry process Wet process Production process Crushing Industrial sector Lime Drying / crushing Aggregates Sawing Washing Ornamental stones Aggregates 3

4 3/3/ Physical characterization (Laser diffraction) Cumulative [%] F F F3 F4 F5 F6 PC, Particle diameter [µm] F F F3 F4 F5 F6 PC d 5 (µm) S S,BET [m /g] Mineralogical and chemical characterization F F F3 F4 F5 F6 Calcite CaCO 3 [%] Quartz SiO [%] Dolomite Ca(Mg,Fe)(CO 3 ) [%] Methylene Blue Adsorption MBA [g/kg filler] Fillers coming from lime production (F, F) and ornamental stones sawing (F4) : high CaCO 3 content. Fillers produced in limestone quarries (F3, F6) : large amounts of impurities. 4

5 3/3/ Bêta-P: spread measurement for different W/P 7 mm,4 τ p Dm + Dm = ( ) D D = mm 6 mm D D,, y =,49x +,734 R =,955 E/P,8,6,4,, τ P D + D D m = D + D D m = Avec Dm [4-5 mm] à t à t + 5min Smooth Paste test (Legrand, 97) Modification of the paste appearance V E correlated with threshold value of dilantancy (rheological behaviour) 5

6 3/3/ Relationship between mortar flowability and MBA or b P of limestone fillers 6,5 5,5 MBA [g/kg filler] 4 3 R =,874,75,5 βp MBA value Bp value R =,84, Flow [mm] Relationship between S S,BET and MBA SS,BET 5 SS,BET [m²/g] 4 3 MBA 4 3 MBA [g/kg filler] F F F3 F4 F5 F6 6

7 3/3/ Materials CEM I 4.5 CEM I 5.5 Limestone Filler Standard sand EN96-:5 (~ mm) Equipments Size and shape characterization Vacuum dispersion Image analysis OCCHIO 5Nano(.5 µm~ mm) 7

8 3/3/ Particle size Traditional equivalent volume (area) diameter Maximum inscribed diameter Passing fraction [%] LF CEM I 5.5 CEM I 4.5 PSD:. Size [µm] Particle shape µm µm µm Length (a) Width (b) Elongation = b a 4π A Circularity = P µm LF CEM I 5.5 CEM I 4.5 χ Fmax Particles >6 µm (>5 pixels/ particle): D im ensional value Circularity LF Circularity CEM I 5.5 Circularity CEM I 4.5 LF Elongation LF Elongation CEM I 5.5 Elongation CEM I 4.5 Holzer et al., by µct &FIB-NT Average inner diameter (µm) 8

9 3/3/ Particle shape 4A Roundness = πχ F max.8 Solidity =A/Ac Convex hull Ac Dimension value.6.4. Solidity LF Solidity CEM I 5.5 Solidity CEM I 4.5 Roundness LF Roundness CEM I 5.5 Roundness CEM I 4.5 χ Fmax A Average inner diameter [µm] Bluntness describes the maturity of the particle in the abrasion process. Bluntness = V Krumbein s chart In which: r V = + N r Calypter tools N max ( ) i r i i Dimension value [-] Bluntness LF Bluntness CEM I 5.5 Bluntness CEM I Average inner diameter [µm] 9

10 3/3/ Dry packing (direct) methods, e.g. BS 8:Part :995 For aggregate For fillers Influences of inter-particle forces? Standard of compaction level? Wet packing (indirect) methods: Standard consistence test, BS EN 96:part 3, 995 the wet packing method (Wong & Kwan, 8) Standard consistence test: The wet packing method (Wong & Kwan, 8) Packing density: Vb M b M φ = = = V V ρ V ( u ρ + ρ ) b w w b The voids ratio (u): V Vb u = = V φ b

11 3/3/ Experiments The wet packing method (Wong & Kwan, 8) The dry packing method Influences of inter-particle forces? Standard of compaction level? Compaction cylinder Concrete vibration table Packing tests The dry packing method.8 Packing density (PD) [-] Sand LF CEM I 5.5 CEM I 4.5 PSD? Shape? Inter-particle forces? Vibration time [s]

12 3/3/ The dry packing method Improved PD percentage [%] Sand LF CEM I 5.5 CEM I Vibration time [s] Increasing rate of PD [X 3 s - ] Sand Vibration time (average in each range) [s] LF CEM I 5.5 CEM I 4.5 The wet packing method Influence of entrapped air Void ratio [-] u w [-] LF CEM I 5.5 CEM I 4.5 Nominal Packing density (PD) [-] u w [-] LF CEM I 5.5 CEM I 4.5 Nominal

13 3/3/ Comparisons of the dry method and the wet packing method.7.6 Wet packing Dry Packing.5 Packing density (-) Limestone fillers (LF) CEM I 5.5 CEM I 4.5 Powder types Discussion on the wet packing method Limitations in the wet packing method manual effects on M-V evaluation Cement hydration Vb M b M φ = = = V V ρ V ( u ρ ρ ) b w w b Superplasticizer Vb M φ = = + V V ( u ρ + ρ + u ρ ) w w b SP SP Packing density (PD) [-] Mixing efficiency (e.g. LF) Real values Nominal values Error percentage 5 4 Error percentage [%] u w [-] 3

14 3/3/ Results on blended cement (total replacement and coarse replacement).6 Packing density (PD) (-) CEM I 4.5 +LF CEM I 5.5+LF CEM I 4.5+LF coarse replacemen 3 Volume fraction of LF (%) Numerical simulations PSD simulations Passing fraction (-) CEM I 4.5 exp. CEM I 4.5 simul. CEM I 5.5 exp. CEM I 5.5 simul. LF exp. LF simul.. Sieve size (µm) 4

15 3/3/ Visualized models Periodical boundaries: CEM I 4.5 CEM I 5.5 LF Rigid boundaries: CEM I 4.5 CEM I 5.5 LF Maximum packing density P o w d e r CEM I 4.5 CEM I 5.5 t y p Limestone fillers e (LF) s Simulation periodical Simulation rigid Dry Packing Wet packing Packing density (-) 5

16 3/3/ Surface to surface nearest neighboring distance (NND) Probability (-) CEM I 4.5 CEM I 5.5 LF Surface-to-surface NND (µm) Surface area density (S V ) and volume density (V V ) in ITZ.8 Sv CEM I 4.5 Vv CEM I 4.5 Sv LF Vv LF Sv CEM I 5.5 Vv CEM I Sv (µm - ) Vv (-) Distance to surface of aggregate (µm) 6

17 3/3/ Mechanical bounding capacities V Meaning free spacing: λ = S 3 A parameter proportional to global bonding capacity :.8 CEM I CEM I 5.5 LF Normalized λ -3 (µm) -3 4 V V λ Stroeven & Stroeven Hu, Distance to surface of aggregate (µm) Permeability.5 ( VV ) λ κ = 3 + 6V V Carman 939 Hu, 4 CEM I 4.5 CEM I 5.5 LF κ (µ m ) Distance to surface of aggregate (µm) 7

18 3/3/ Conclusions The limestone fillers collected in Belgium differ from each other through their physico-chemical characteristics (impurities such as clay, quartz and dolomite). The water requirement of limestone fillers is mainly influenced by their clay content (indicated by high MBA and S S,BET values). Size and shape characteristics of LF and OPC can be identified by an advanced image analysis system. With a proper replacement of cement by LF, packing density of the mixture can be improved. Filler effect is significant as also illustrated by the numerical simulation. Conclusions Influence of clay in limestone fillers for self-compacting cement based composites. L. Courard, F. Michel and J. Piérard. Construction Building Materials 5() Influence of physico-chemical characteristics of limestone fillers on fresh and hardened mortar performances. F. Michel, J. Piérard, L. Courardand V. Pollet. In: 5th International RILEM Symposium on Self-Compacting Concrete, Proceedings PRO 54 (Eds. G. De Schutter and V. Boel, Rilem Publications), Gent, Belgium (September 3-5, 7), pp. 5-. Characterization of fine aggregate in concrete by different experimental approaches () He, H., Courard, L., Pirard, E. andmichel F. ICS-3, the 3th International Congress of Stereology, Oct. 9-3,, Beijing, China. Particle packing density and limestone fillers for more sustainable cement () He, H., Courard, L. and Pirard, E., 3 th International Conference on Non-conventional Materials and Technologies(3 NOCMAT ),Sep. -4,, Changsha, China. 8

19 3/3/ Thank you for your attention Hvala Merci Dziękuję Thank you Dank u Grazie Danke Gratias Arigato Efkaristos 9