20/10/2015. Results: Part 1. Elucidation of the molecular architecture of the SPs

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Introduction Lime mortars used in the Built Heritage over centuries lime, usually air lime, as the binding material renders, repair mortars and other mixes.

(NS) and metakaolin (MK) have been extensively used as Supplementary Cementitious Materials to improve the mechanical strength and to short the setting time of air lime mortars.

5 Introduction Lime mortars used in the Built Heritage over centuries lime, usually air lime, as the binding material renders, repair mortars and other mixes. ROLE OF DIFFERENT SUPERPLASTICIZERS ON HYDRATED LIME PASTES AND MORTARS Duran, A., Navarro-Blasco, I., Pérez-Nicolás, M., Sirera, R., Fernández, J.M., Alvarez, J.I. Lime mortars pozzolanic additives: hydraulic mortars Nanosilica (NS) and metakaolin (MK) have been extensively used as Supplementary Cementitious Materials to improve the mechanical strength and to short the setting time of air lime mortars. Air lime mortars pozzolanic add. SUPERPLASTICIZERS Department of Chemistry and Soil Sciences, Research Group on Inorganic Materials & Environment UNIVERSITY OF NAVARRA Beijing, October, 2015 AIM OF THIS WORK to gain a better understanding on the behavior of different SPs in lime-bearing pastes and mortars Materials Air lime pastes and mortars were obtained by mixing Raw materials: Air lime (CL90) limestone aggregate (1:3, w:w) Pozzolanic additives: Nanosilica or Metakaolin (6, 10 and 20% bwoc) Superplasticizers (0.5 and 1% bwoc): Materials TEM micrographs showing the particle size as well as the shape of the pozzolanic additives spherical shape, 500 m 2 /g card-house agglomerations, 20 m 2 /g two different polycarboxylate ethers (PCE1 and PCE2) 500nm 4000 nm a polynaphthalene sulfonate-based (PNS) polymer Nanosilica Metakaolin a lignosulfonate (LS) Superplasticizers molecules were studied by means of different techniques: SEC, FTIR-ATR, MALDI-TOFF mass spectrometry, anionic charge density, acid-base titration and elemental analysis. Results: elucidation of the molecular architecture of the SPs Results of the MALDI-TOFF (Matrix Assisted Laser Desorption Ionization Timeof-Flight) analysis Results: Part 1 Elucidation of the molecular architecture of the SPs For PCE1: wide range of signal intensities (mass-to-charge m/z ratios) position of the most intense signal Longer side chains and higher Mw than that of PCE2 Navarro-Blasco I, Pérez-Nicolás M, Fernández JM, Duran A, Sirera R, Alvarez JI. Assessment of the interaction of polycarboxylate superplasticizers in hydrated lime pastes modified with nanosilica or metakaolin as pozzolanic reactives. Constr Build Mater 2014;73:

Results: elucidation of the molecular architecture of the SPs Results: elucidation of the molecular

Timeof-Flight) analysis For PCE1: Lower anionic charge density Larger Mw Longer side length For PCE2:

groups) Longer main backbone (high amount of COO - groups) For PCE2: narrower m/z distribution lower m/z

Navarro-Blasco I, Pérez-Nicolás M, Fernández JM, Duran A, Sirera R, Alvarez JI.

nanosilica or metakaolin as pozzolanic reactives. Constr Build Mater 2014;73:1-12.

POLYNAPHTHALENESULFONATE Results: Part 2 Fresh state properties of the air lime samples with

$measurements (laser diffraction) Formation of large agglomerations in the presence of NS lime20%ns$ lime10%mk lime lime10%ns lime6%mk lime6%ns lime6%ns lime6%mk lime10%ns lime10%mk lime20%ns lime20%mk

lime10%mk lime lime10%ns lime6%mk lime6%ns lime6%ns lime6%mk lime10%ns lime10%mk lime20%ns lime20%mk

Long-term mechanical resistance and durability of air lime mortars with large additions of nanosilica.

6 Results: elucidation of the molecular architecture of the SPs Results: elucidation of the molecular architecture of the SPs Results of the MALDI-TOFF (Matrix Assisted Laser Desorption Ionization Timeof-Flight) analysis For PCE1: Lower anionic charge density Larger Mw Longer side length For PCE2: Higher anionic charge density Lower Mw Shorter side length Short main backbone (low amount of COO - groups) Longer main backbone (high amount of COO - groups) For PCE2: narrower m/z distribution lower m/z ratio PCE2 shorter side chains (with identical width between the oligomer peaks) and lower Mw. Navarro-Blasco I, Pérez-Nicolás M, Fernández JM, Duran A, Sirera R, Alvarez JI. Assessment of the interaction of polycarboxylate superplasticizers in hydrated lime pastes modified with nanosilica or metakaolin as pozzolanic reactives. Constr Build Mater 2014;73:1-12. PCE1 Results: elucidation of the molecular architecture of the SPs LIGNOSULFONATE POLYNAPHTHALENESULFONATE Results: Part 2 Fresh state properties of the air lime samples with superplasticizers SEC results: Mw ACID-BASE TITRATION: PNS 2.44 meq of anionic charge/g of polymer LS 1.04 meq of anionic charge/g of polymer lime20%mk Slump values of SPfree samples Particle size measurements (laser diffraction) Formation of large agglomerations in the presence of NS lime20%ns lime10%mk lime lime10%ns lime6%mk lime6%ns lime6%ns lime6%mk lime10%ns lime10%mk lime20%ns lime20%mk lime Duran A, Navarro-Blasco I, Fernández JM, Alvarez JI. Long-term mechanical resistance and durability of air lime mortars with large additions of nanosilica. Constr Build Mater 2014;58: Fernández JM, Duran A, Navarro-Blasco I, Lanas J, Sirera R, Alvarez JI. Influence of nanosilica and a polycarboxylate ether superplasticizer on the performance of lime mortars. Cem Concr Res ;43(0):

$Particle size measurements (laser diffraction) Disappearance of the large agglomerations Slump values of air lime samples 0.75% PNS 0.$ Influence of nanosilica and a polycarboxylate ether superplasticizer on the performance of lime mortars.

Influence of nanosilica and a polycarboxylate ether superplasticizer on the performance of lime mortars.

% of nanosilica Slump values of samples with 10 wt.% of metakaolin 0.75% PNS 0.50% 0.75% PNS 0.50% PNS 0.75% PCE2 0.75% 0.25%PCE2 0.75% PCE1 0.25%PCE2 0.50% PCE1 0.50% 0.75% PCE2 PCE1 0.75% 0.25%PCE2 0.25% 0.

7 Particle size measurements (laser diffraction) Disappearance of the large agglomerations Slump values of air lime samples 0.75% PNS 0.50% PCE1 0.50% PNS 0.75% PCE1 0.25%PCE2 0.75% PCE2 0.75% PCE2 0.50% PNS 0.75% PNS 0.25%PCE2 Addition of PCE1 Disappearance of the large agglomerations 0.75% PCE1 0.50% PCE1 Fernández JM, Duran A, Navarro-Blasco I, Lanas J, Sirera R, Alvarez JI. Influence of nanosilica and a polycarboxylate ether superplasticizer on the performance of lime mortars. Cem Concr Res ;43(0): Slump (mm) Slump values of samples with 10 wt.% of nanosilica Slump values of samples with 10 wt.% of nanosilica Slump values of samples with 10 wt.% of metakaolin 0.75% PNS 0.50% 0.75% PNS 0.50% PNS 0.75% PCE2 0.75% 0.25%PCE2 0.75% PCE1 0.25%PCE2 0.50% PCE1 0.50% 0.75% PCE2 PCE1 0.75% 0.25%PCE2 0.25% 0.50% PNS PCE2 0.50% 0.75% PNS PCE2 0.75% PNS 0.50% PNS 0.75% LS 0.75% PNS 0.50% PNS 0.75% PCE2 0.25%PCE2 0.75% PCE1 0.50% PCE1 0.50% PCE1 0.75% PCE1 0.25%PCE2 0.75% PCE2 0.50% PNS 0.75% PNS 0.50% PCE1 0.25%PCE Slump (mm) Slump loss over the time: air lime pastes Slump loss over the time: air lime nanosilica Slump (mm) LimePCE1 LimePCE2 LimePNS LimeLS Slump (mm) LimeNSPCE1 LimeNSPCE2 LimeNSPNS LimeNSLS Increasing time after mixing of the fresh sample Increasing time after mixing of the fresh sample PCE1 and LS showed the best slump retention abilities 3

Slump (mm) 340 320 300 280 260 240 220 200 180 160 140 Slump loss over the time: air lime metakaolin LimeMKPCE1 LimeMKPCE2 LimeMKPNS LimeMKLS 120 0 20 40 60 80 100 120 140 Increasing time after

PCE2 was adsorbed in a 3- to 4-fold when compared with PCE1, in plain air lime samples.

Langmuir and Freundlichadsorption parameters for both PNS and LS Polynaphthalenesulfonate Langmuir model Freundlich model q m b R 2 K 1/n R 2 (mg g -1 ) (dm 3 mg -1 ) (mg 1-1/n dm 3/n g -1 ) Zeta

-3 10%NS 3174.60 1.51 10 0.878 6.6 10 0.954 0.998. -6. -3 20%NS 3311.26 1.44 10 0.450 4.9 10 0.996 1.

982 8.32. 10-3 0.904 0.998 10%NS 151.52 2.92. 10-5 0.987 6.46. 10-3 0.941 0.999 20%NS 303.03 1.46. 10-5 0.958 5.44. 10-3 0.968 1.

S H dispersion The polymer adsorbed onto NS was not able to be adsorbed onto C S H the overall zeta potential was modified to a limited extent for NS-bearing samples Electric double layer Particle

Na ) PCE1: star-shaped polymer with negatively charged backbone PCE2: worm-like polymer (larger negatively charged backbone) Flat adsorption Particle surface SiO SiO SiO SiO Displaced shear plane

8 Slump (mm) Slump loss over the time: air lime metakaolin LimeMKPCE1 LimeMKPCE2 LimeMKPNS LimeMKLS Increasing time after mixing of the fresh sample Adsorption isotherms of the PCEs assayed onto plain lime, lime-ns and lime-mk pastes (20 wt. % of pozzolanic additive) fitted acording to Freundlich model. PCE2 was adsorbed in a 3- to 4-fold when compared with PCE1, in plain air lime samples. high consumption of polycarboxylates in the presence of pozzolanic additives high specific surface area (500 m 2 g -1 nanosilica). Langmuir and Freundlichadsorption parameters for both PNS and LS Polynaphthalenesulfonate Langmuir model Freundlich model q m b R 2 K 1/n R 2 (mg g -1 ) (dm 3 mg -1 ) (mg 1-1/n dm 3/n g -1 ) Zeta potential of lime-ns and lime-mk pastes titrated with the PCE superplasticizers 0%NS %NS %NS %NS Lignosulfonate Langmuir model q m b (mg g -1 ) (dm 3 mg -1 ) R 2 Freundlich model K 1/n R 2 (mg 1-1/n dm 3/n g -1 ) 0%NS %NS %NS %NS High affinity of PNS for air lime particles Large PNS adsorption onto solid particles Great interaction of PNS with air lime media NS presented no active adsorption sites in connection with the C S H dispersion The polymer adsorbed onto NS was not able to be adsorbed onto C S H the overall zeta potential was modified to a limited extent for NS-bearing samples Electric double layer Particle surface SiO SiO SiO SiO Shear plane Perpendicular adsorption Particle surface SiO SiO SiO SiO Released anions OH - anions Displaced shear plane positive ions (e.g. Na ) PCE1: star-shaped polymer with negatively charged backbone PCE2: worm-like polymer (larger negatively charged backbone) Flat adsorption Particle surface SiO SiO SiO SiO Displaced shear plane Released anions The decrease in the zeta potential was caused in PCE1 PCE2 by: the compensation displacement of the shear positiveplane charge of the of outer the Helmholtz external layer layer of Ca owing 2 ions to by the the side negatively chainscharged of the polycarboxylate copolymers units Navarro-Blasco I, Pérez-Nicolás M, Fernández JM, Duran A, Sirera R, Alvarez JI. Assessment of the interaction of polycarboxylate superplasticizers in hydrated lime pastes modified with nanosilica or metakaolin as pozzolanic reactives. Constr Build Mater 2014;73:1-12. Setting time (min) The PCEs attachment onto NS retarded the pozzolanic reaction between NS and Ca(OH) 2 the increasing amounts of superplasticizers caused stronger delays in the setting time as compared with lime MK samples. PCE 1 PCE Increasing dosage of superplasticizer (%) Air lime pastes with 10 wt.% of NS Setting time (min) Air lime pastes with 10wt.% of MK low adsorbed amounts of PCE1 better dispersing action of PCE1 requires lower dosage of plasticizing agent steric hindrance was then the main action mechanism of these PCEs 0 PCE 1 PCE Increasing dosage of superplasticizer (%) 4

Zeta potential of lime-ns and lime-mk pastes titrated with PNS and LS Polynaphthalene sulfonate higher anionic charge density flat adsorption linear shape attached molecules surrounded by the growing

lower dispersion effectiveness, poor dispersion maintaining ability PNS caused a sharper decrease in zeta potential LS produced Ca 2 complex salts, with low adsorption onto portlandite or CSH LS

9 Zeta potential of lime-ns and lime-mk pastes titrated with PNS and LS Polynaphthalene sulfonate higher anionic charge density flat adsorption linear shape attached molecules surrounded by the growing carbonation/hydration products, yielding organo-mineral phases. lower dispersion effectiveness, poor dispersion maintaining ability PNS caused a sharper decrease in zeta potential LS produced Ca 2 complex salts, with low adsorption onto portlandite or CSH LS yielded higher slump values and presented a lower slump loss over the time Lignosulfonate adsorption would be more perpendicular to the surface of the particles. free LS molecules in the interstitial solution may act as a steric hindrance to prevent particles from agglomeration Compressive strength values of mortars with PCEs 9 8 Results: Part 3 Influence of the SPs on the mechanical strength and durability of the tested mortars Compressive strength (N/mm2) Control group 20% NS 0% NS - 0.5% SPP1 20%NS - 0.5% SPP1 20%NS - 1% SPP1 0% NS - 0.5% SPP2 20%NS - 0.5% SPP2 20%NS - 1% SPP2 dv/dlogd (ml.g -1 ) Control group NS-PCE 0.5% NS-PCE 1.0% MIP analysis values of mortars with PCE1 Macropores reduction SEM examination of mortars with PCE1 Admixture-free mortar PCE-NS mortar , Pore diameter ( m) 0.45 Total porosity reduction (AUC) Mean pore size peak displacement dv/dlogd (ml.g -1 ) Control group NS-PCE 0.5% 0.25 NS-PCE 1.0%, 0.20 fixed mixing water 0.15 NS-PCE 1.0% The textural characteristics (SEM) showed reduced porosity, and, on the other hand, the growing of calcite crystals resulted in a more homogeneous and continuous matrix, allowing the aggregate particles to be embedded. Pore diameter ( m) Alvarez JI, Fernández JM, Navarro-Blasco I, Duran A, Sirera R. Microstructural consequences of nanosilica addition on aerial lime binding materials: influence of different drying conditions. Mater Charact 2013;80:36-49 Fernández JM, Duran A, Navarro-Blasco I, Lanas J, Sirera R, Alvarez JI. Influence of nanosilica and a polycarboxylate ether superplasticizer on the performance of lime mortars. Cem Concr Res ;43(0):

Compressive strength values of mortars with PNS and LS 20% NS - 1% PNS 20% NS - 1% LS The micrograph of the LS-bearing sample depicts a wide area covered by C-S-H

5% SPP2 0% NS 0.5% SPP2 20%NS 1% SPP1 10% NS 1% SPP1 6% NS 1% SPP1 0% NS 1% SPP1 20%NS 0.5% SPP1 10% NS 0.5% SPP1 6% NS 0.5% SPP1 0% NS 0.

Duran A, Navarro-Blasco I, Fernández JM, Alvarez JI. Long-term mechanical resistance and durability of air lime mortars with large additions of nanosilica.

Conclusions 1) star-shaped polymer PCE1 as compared to PCE2 (worm like polymer) The lowest anionic charge density The largest plasticizing effect in the assayed lime

its use as grout Better mechanical resistance and durability (freezing thawing cycles) PCE2 Conclusions 2) LS as compared to PNS More effective in increasing the

10 Compressive strength values of mortars with PNS and LS 20% NS - 1% PNS 20% NS - 1% LS The micrograph of the LS-bearing sample depicts a wide area covered by C-S-H crystals freezing thawing cycles durability Specimens 20%NS 1% SPP2 10% NS 1% SPP2 6% NS 1% SPP2 0% NS 1% SPP2 20%NS 0.5% SPP2 10% NS 0.5% SPP2 6% NS 0.5% SPP2 0% NS 0.5% SPP2 20%NS 1% SPP1 10% NS 1% SPP1 6% NS 1% SPP1 0% NS 1% SPP1 20%NS 0.5% SPP1 10% NS 0.5% SPP1 6% NS 0.5% SPP1 0% NS 0.5% SPP1 20% NS 10% NS 6% NS Control group Decay degree none scarce moderate large total Conclusions F/T cycles Duran A, Navarro-Blasco I, Fernández JM, Alvarez JI. Long-term mechanical resistance and durability of air lime mortars with large additions of nanosilica. Constr Build Mater 2014;58: Conclusions 1) star-shaped polymer PCE1 as compared to PCE2 (worm like polymer) The lowest anionic charge density The largest plasticizing effect in the assayed lime pastes The lowest comsumption (low amount of adsorbed polymer) Perpendicular adsorption Steric hindrance With metakaolin provided the best flowability in order to its use as grout Better mechanical resistance and durability (freezing thawing cycles) PCE2 Conclusions 2) LS as compared to PNS More effective in increasing the fluidity of the samples Able to form Ca 2 complexes Large number of free LS molecules in the suspension Strong steric effect Favoured the formation of C-S-H 3) PNS Formation of organo-mineral phases that increased its consumption Poor plasticizing performance Low slump retention capacity Electrostatic repulsion as the main dispersion mechanism PCE1 6

4 th Historic Mortars Conference HMC2016

4 th Historic Mortars Conference HMC2016 Laboratory of of of Building Materials Department of of Civil Engineering Aristotle University of of Thessaloniki Proceedings of the HMC2016 10 th -12 th October 2016, Santorini, Greece Editors Ioanna