1. No category

Geopolymers with reduced density for applica5on as structural elements in energy efficient buildings Glikeria Kakali [email protected] V. Pavlakou, A. Skaropoulou, S. Tsivilis Na:onal Technical University of Athens, School of Chemical Engineering, Athens, Greece EinB2014 -­‐ 3rd Interna:onal Conference “ENERGY in BUILDINGS 2014” What are geopolymers? Raw materials: Aluminosilicate materials + alkaline solu5on =
+
Process Raw materials Ac5va5on solu5on Mixing Moulding Curing t=48 h, T=50-­‐90oC t=7 d, T=RT EinB2014 -­‐ 3rd Interna:onal Conference “ENERGY in BUILDINGS 2014” 2 Why geopolymers? wastes as raw materials Ø  green materials low embodied energy low CO2 footprint Ø  tailored proper5es Ø  low cost materials and process strength development Ø enhanced proper5es fire resistance acid/base resistance EinB2014 -­‐ 3rd Interna:onal Conference “ENERGY in BUILDINGS 2014” 3 Drawbacks? Ø  Raw materials varia5on Ø  Lack of data on long term durability Ø  Adherence to composi5onally-­‐based building codes and standards Ø  Conserva5ve nature of the construc5on and building products industry with regard to new products EinB2014 -­‐ 3rd Interna:onal Conference “ENERGY in BUILDINGS 2014” 4 Worldwide Research Ac5vity EinB2014 -­‐ 3rd Interna:onal Conference “ENERGY in BUILDINGS 2014” 5 Commercial Products Company
Country
Products
site
WAGNERS
ZEOBOND
Australia
Australia
www.wagner.com.au/
www.zeobond.com
BANAH UK
SCHLUMBERG ER
UK
USA
Nu-Core®
Australia
China
Concrete
Cement, Concrete,
Pre-cast walls
Cement, Concrete
Cement,
Sealing materials
Fire resistant panels
CORNING Inc
AIRBUS
PYROMERAL Sys
ÉIRECOMPOSITES TEO
USA
France
France
Ireland
Ceramics
Composite materials
Composite materials
Composite materials
www.banahuk.co.uk
www.slb.com
www.nu-core.com.au
www.nu-core.com.cn
www.corning.com
www.airbus.com
www.pyromeral.com
www.eirecomposites.com
EinB2014 -­‐ 3rd Interna:onal Conference “ENERGY in BUILDINGS 2014” 6 Experimental: Materials Fly Ash (Megalopolis) Chemical composi5on (%w/w) SiO2 Al2O3 Fe2O3 CaO MgO K2O Na2O SO3 L.O.I. 47.86 23.54 7.15 10.56 2.28 1.58 -­‐ 2.50 4.30 Mineral composi5on: Quartz, feldspars, anhydrite, ghelenite, maghemite Fineness: d50 ~ 20 μm Ac5va5on Solu5on Na Waterglass: SiO2/Na2O:3.34, density: 1.37 g/cm3 EinB2014 -­‐ 3rd Interna:onal Conference “ENERGY in BUILDINGS 2014” 7 Geopolymeriza5on of fly ash P. Duxson et al, J Mater Sci (2007) 42:2917–2933
EinB2014 -­‐ 3rd Interna:onal Conference “ENERGY in BUILDINGS 2014” 8 Op5miza5on of synthesis Optimization of curing
conditions
Op$miza$on of curing condi$ons Op$miza$on of synthesis EinB2014 -­‐ 3rd Interna:onal Conference “ENERGY in BUILDINGS 2014” 9 Op5miza5on of geopolymer composi5on Parameters Si/Al=2.20-­‐2.50 Na/Al=0.65-­‐0.95 solids/liquid=2.80-­‐3.40 Op$mum condi$ons Si/Al=2.40 – Na/Al=0.85 – s/l=3.20 Proper5es: Compresive strength: 55 MPa Bending strength: 2 MPa Density: 1.77 g/cm3 EinB2014 -­‐ 3rd Interna:onal Conference “ENERGY in BUILDINGS 2014” 10 Prepara5on of lightweight geopolymer Incorpora5on of expanded polystyrene ü  Common PS ü  Sphere (1-­‐3 mm) ü  Sphere (3-­‐5 mm) ü  PS -­‐ 1% polywex -­‐ 6% pentane ü  PS -­‐ 1% graphene -­‐ 6% pentane ü  Coperion Incorpora5on of foaming agents ü  H2O2 H2O2→H2O + ½ O2 ü  Me: Al, Si, Zn xH2O + Me→0.5xH2 + Me(OH)x ü  Silica fume (free Si < 1% w/w) EinB2014 -­‐ 3rd Interna:onal Conference “ENERGY in BUILDINGS 2014” 11 GEOP + PS: Compressive strength -­‐ Density Common Expanded Polystyrene
1.5
40
30
1
20
0.5
10
0
0
0.5
1.0
1.5
50
30
1
% exp pol
compressive strength
2
density
PS, 1% Polywex, 6% pentane
2
1
0.5
0
2
60
compressive
strength (MPa)
1.5
density (g/cm3)
compressive
strength (MPa)
0
0
density
60
50
40
30
20
10
0
2
50
1.5
40
30
1
20
0.5
10
0
0
0
% exp pol
compressive strength
0.5
10
PS, 1% graphene, 6% pentane
1
1
20
% w/w polystyrene
0
1.5
40
0
2.0
compressive strength
2
density
density (g/cm3)
0.0
compressive
strength (MPa)
60
dencity (g/cm3)
2
50
density (g/cm3)
compressive
strength (MPa)
60
Coperion PS
1
% exp pol
compressive strength
EinB2014 -­‐ 3rd Interna:onal Conference “ENERGY in BUILDINGS 2014” 2
density
12 GEOP + PS 2 % w/w: Compressive strength -­‐ Density EinB2014 -­‐ 3rd Interna:onal Conference “ENERGY in BUILDINGS 2014” 13 GEOP + Al: Effect of synthesis condi5ons EinB2014 -­‐ 3rd Interna:onal Conference “ENERGY in BUILDINGS 2014” 14 GEOP + Al: Microstructure Reference GEOP Reference GEOP + 0.1% w/w Al EinB2014 -­‐ 3rd Interna:onal Conference “ENERGY in BUILDINGS 2014” 15 GEOP + Al: Compressive strength -­‐ Density Higher strength: ♦Fiber reinforcement ♦Uniform pore size distribu5on EinB2014 -­‐ 3rd Interna:onal Conference “ENERGY in BUILDINGS 2014” 16 Silica fume as foaming agent Raw materias Mass Ratios Foaming effect Silica fume -­‐ Metakaolin 1:1 yes Silica fume – F ly ash 1:1 no Silica fume – F ly ash 1:4 no Silica fume – Metakaolin -­‐ Fly ash 1:1:1 no Silica fume – Metakaolin -­‐ Fly ash 1:1:3 no Silica fume – Metakaolin -­‐ Fly ash 2:2:1 little EinB2014 -­‐ 3rd Interna:onal Conference “ENERGY in BUILDINGS 2014” 17 Conclusions v  Fly ash (Megalopolis) can be used for the synthesis of geopolymers. The compressive strength depends on Si/Al and Na/Al ra5os (60 MPa for Si/Al:2.4, Na/Al: 0.95). v  The addi5on of expanded polystyrene grains can lower the density by 20-­‐40%, with corresponding compressive strength from 20 to 8 MPa. v  The addi5on of Al can lower the density by 25-­‐55%, with
corresponding compressive strength from 4 to 12 MPa. v  Silica fume works as a foaming agent in combina5on with metakaolin, but the presence of fly ash inhibits the foaming reac5on, probably due to the high iron content. EinB2014 -­‐ 3rd Interna:onal Conference “ENERGY in BUILDINGS 2014” 18 Geopolymers with reduced density for applica5on as structural elements in energy efficient buildings Glikeria Kakali [email protected] EinB2014 -­‐ 3rd Interna:onal Conference “ENERGY in BUILDINGS 2014” 19