The influence of the metakaolinite addition on the hydration process of the alkali-activated synthetic gehlenite glasses Ł. Gołek, J. Deja Montreal July 11, 2007 AGH University of Science and Technology Faculty of Materials Science and Ceramics Kraków, Poland 12TH INTERNATIONAL CONGRESS ON THE CHEMISTRY OF CEMENT

Alkaline activation Alkaline activation Hydration process Hydration process -hydration with metakaolinite addition Synthetic gehlenite glasses Synthetic gehlenite glasses Examination of hydrated samples Examination of hydrated samples Conclusions Conclusions Scope of presentation

Alkaline activation Types of activators Types of activators Amount of activator Amount of activator Activation of slags Activation of slags Activation with highly concentrated solutions Activation with highly concentrated solutions

Hydration processes with activators Hydration processes with activators Hydration process slag glass Na +, K +, OH –... Ca 2+ [H 2 SiO 4 ] 2– Mg 2+ [Al(OH) 4 ] –

Hydration processes with activators Hydration processes with activators Hydration process Na +, H 2 O C-S-H (C/S ~ 1,0) slag glass

Hydration processes with activators and mineral additions Hydration processes with activators Hydration processes with activators Geopolymers Hydration process C-S-H (C/S ~ 1,0) slag glass Na +, K +, OH –...

Hydration process GEOPOLYMERS SlagMetakaolinAlkalies 5÷15 M NaOH KOH

Polymeric precursors – SiO 4 – AlO 4 – – SiO 4 – AlO 4 – SiO 4 – – SiO 4 – AlO 4 – SiO 4 – SiO 4 –

Experimental

Synthetic glasses Melilite glasses Melilite glasses Gehlenite glasses Gehlenite glasses Glass Content [%] Amount of moles [per 100g] Molar ratio Al 2 O 3 /SiO 2 CaOAl 2 O 3 SiO 2 CaOAl 2 O 3 SiO 2 B 1, C 1, Glass Content [%] Amount of moles [per 100g] Molar ratio Al 2 O 3 /SiO 2 CaOAl 2 O 3 SiO 2 MgOCaOAl 2 O 3 SiO 2 MgO A 0,

Composition of samples Designation Amount of the glass [%] Amount of the MK [%] Amount of the activator [%] Na 2 O AN1, AN3, AN AMN1, AMN3, AMN BN1, BN3, BN BMN1, BMN3, BMN CN1, CN3, CN CMN1, CMN3, CMN

Examinations of hardened samples Heat of hydration Heat of hydration Compressive strength Compressive strength XRD XRD IR IR NMR NMR

Examinations of pastes setting time and heat of hydration Designation Water-cement ratio Setting time Compressive strength [MPa] Heat of hydration, Q 24h, J/g AN1 0.24~24h AN3 0.24~24h AN7 0.24~24h AMN1 0.24~24h3.065 AMN3 0.24~24h AMN7 0.24~24h

Examinations of pastes setting time and heat of hydration Designation Water-cement ratio Setting time Compressive strength [MPa] Heat of hydration, Q 24h, J/g BN1 0.40~10 seconds BN3 0.40~10 seconds BN7 0.40~10 seconds BMN1 0.40~20 seconds BMN3 0.40~20 seconds BMN ~20 seconds

Examinations of pastes setting time, heat of hydration Designation Water-cement ratio Setting time Compressive strength After 28 days [MPa] Heat of hydration, Q 24h, J/g CN1 0.38~120 seconds CN3 0.38~30 seconds CN7 0.38~20 seconds CMN min CMN min CMN min

Examinations of hardened samples XRD CSH CN7 CN3 CN1 BN3 BN1 AN7 AN3 AN1 HT S S CASH/S S A/S S S CASH A/S C C A CASH/S BN7

Examinations of hardened samples XRD CMN7 CMN3 CMN1 BMN7 BMN3 BMN1 AMN7 AMN3 AMN1 CASH/S S A/S Z S CSH A/S S Q CA S A A Z Z S ZSS Z Q S

Examinations of hardened samples IR AN1 AMN1 BN1 BMN1 CN1 CMN1 ~540cm -1 ~3440cm -1 ~1620cm -1 ~1490cm -1 ~1010cm -1 ~860cm ~1100cm -1 ~800cm -1 ~460cm -1 OH groups Si-O-Si symetric Cyclic structures (Zeolites) O-Si-O (tetrahedral) Skeleton structure Carbonate groups Terminal bonds Si-O H2OH2O

Examinations of hardened samples SEM (AN3) Counts Energy [keV] Counts 3

Examinations of hardened samples EDS (AMN3) Energy [keV] Counts 3 Energy [keV] Counts 2 Energy [keV] Counts

Examinations of hardened samples EDS (BN3) Energy [keV] Counts 1 1 1

Examinations of hardened samples EDS (BMN3) Energy [keV] Counts Energy [keV] Counts

Examinations of hardened samples EDS (CN3) Energy [keV] Counts Energy [keV] Counts Energy [keV] Counts 3 3

Examinations of hardened samples EDS (CMN3) Energy [keV] Counts Energy [keV] Counts

Examinations of hardened samples NMR raw Hyd. ppm from TMS 29 Si NMR 8 kHz MAS A raw Hyd. ppm from TMS 29 Si NMR 8 kHz MAS B raw Hyd. ppm from TMS 29 Si NMR 8 kHz MAS C

Conclusions The influence of Al2O3/SiO2 molar ratio is significant The differences in the rates of hydration and also in the kind of hydration products were observed The MK addition has a tremendous influence on the rate of hydration process and on the properties and kind of forming phases The highly developed surface of MK causes decrease of mechanical properties of the samples The concentration of activator has a major influence on the rate of hydration process and amount of crystalline phases In case of pastes without the MK addition, more crystalline products with lower concentration of activator were observed

Ł. Gołek, J. Deja Thank you for attention Montreal July 11, 2007 AGH University of Science and Technology Faculty of Materials Science and Ceramics Kraków, Poland 12TH INTERNATIONAL CONGRESS ON THE CHEMISTRY OF CEMENT