Geopolymer material for panels
A geopolymeric material is described having compressive strength at 28 days ranging from 15 to 100 N/mm 2 , obtainable by curing for 12 hours at a temperature ranging from 20° C. to 60° C., from a geopolymeric aqueous mixture comprising the following inorganic components in the following parts by dry mass: metakaolin 15-65 potassium silicate and/or sodium silicate 20-40 aggregates recycled from CDW (Construction and Demolition Waste) 5-300; said geopolymeric aqueous mixture is obtainable by mixing 20-175 parts by mass of water with said inorganic components, and has a viscosity at 23° C. between 100 and 10000 Pa·s, wherein: i) the viscosity is measured via Brookfield methodology, ii) the aggregates recycled from CDW belong to one or more of the classes 17.01.01, 17.01.02, 17.01.03, 17.01.07 according to the European Waste Catalogue, iii) the aggregates recycled from CDW have a grain size less than or equal to 4 mm, preferably less than or equal to 2 mm.
1 . A geopolymeric aqueous mixture comprising the following inorganic components in the following parts by dry mass:
metakaolin 15-65
potassium silicate and/or sodium silicate 20-40
aggregates recycled from Construction and Demolition Waste (CDW) 5-300
blast furnace slag 0-60
fly ash 0-25
sodium citrate 0-25,
said geopolymeric aqueous mixture being obtained by:
mixing 20-175 parts by mass of water with said inorganic components, said geopolymeric aqueous mixture having a viscosity at 23° C. between 100 and 10000 Pa·s, wherein
i) viscosity is measured via Brookfield methodology,
ii) said aggregates recycled from CDW belong to one or more of the classes 17.01.01, 17.01.02, 17.01.03, 17.01.07 according to the European waste catalogue,
said aqueous geopolymeric mixture being selected from the following ones:
an aqueous geopolymeric mixture ( 1 ):
having: a viscosity at 23° C. between 100 and 150 Pa·s, a working time at 23° C. of not less than 70 min;
and consisting of metakaolin:blast furnace slag:fly ash:potassium silicate CDW:Total H 2 O in the corresponding parts by mass 34:23:11:31:93:38, wherein the molar ratio Si/Al˜2.2 and the molar ratio K/Al˜0.80, wherein the potassium silicate has a molar ratio SiO 2 /K 2 O=1.9 and a solvation water content of 38 parts by mass and the CDW is a blend consisting of concrete and bricks with a particle size of 1 to 2 mm and 0 to 1 mm, with the two particle size fractions mixed in a mass proportion between 3:2 and 2:1, respectively;
a thixotropic aqueous geopolymeric mixture (II):
with viscosity at 23° C. between 2000 and 5000 Pa·s and
consisting of metakaolin:blast furnace slag:fly ash:potassium silicate CDW:Total H 2 O in parts by weight respectively of 37:37:0:27:100:32-41 wherein the molar ratio Si/Al˜2.3 and the molar ratio K/Al˜0.75, wherein the potassium silicate has a molar ratio SiO 2 /K 2 O=1.9 and a solvation water content of 32 parts by mass and the CDW has a particle size of less than 2 mm; and
a thixotropic aqueous geopolymeric mixture (III):
with viscosity at 23° C. between 2000 and 5000 Pa·s
consisting of metakaolin:blast furnace slag:fly ash:potassium silicate:CDW:Total H 2 O in parts by weight respectively of 38:38:0:24:70:30-36 wherein the molar ratio Si/Al˜2.0 and the molar ratio K/Al˜0.75, wherein the potassium silicate has a molar ratio SiO 2 /K 2 O=1.4 and a solvation water content of 30 parts by mass and wherein the CDW has a particle size of less than 2 mm.
2 . The geopolymeric aqueous mixture of claim 1 , wherein the blast furnace slag and fly ash have a particle size such that D50 is less than or equal to 20 microns.
3 . The geopolymeric aqueous mixture according to claim 1 , further comprising a percentage by volume between 0.2% and 3% of polymeric and/or metallic and/or mineral fibres.
4 . A geopolymeric material obtained by curing the aqueous mixture (I) according to claim 1 , wherein the geopolymeric material has a compressive strength at 28 days ranging from 35 to 40 N/mm 2 and a drying shrinkage of less than 0.22% after 6 months obtained by curing for 12 hours at 50° C.
5 . A geopolymeric material obtained by curing the aqueous mixture (II) according to claim 1 , wherein the geopolymeric material has a compressive strength at 28 days ranging from 70 to 80 N/mm 2 and a drying shrinkage of less than 0.12% after 3 months obtained by curing at 30° C. for 12 hours.
6 . A geopolymeric material obtained by curing the aqueous mixture (III) according to claim 1 , wherein the geopolymeric material has a compressive strength at 28 days ranging from 85 to 95 N/mm 2 obtained by curing at 30° C. for 12 hours.
7 . A panel consisting of the geopolymeric material according to claim 5 .
8 . The geopolymeric aqueous mixture of claim 1 , wherein said aggregates recycled from CDW have a grain size less than or equal to 2 mm.
9 . A panel comprising:
a layer consisting of the geopolymeric material of claim 4 ,
an insulating layer adjacent to said cured geopolymeric material layer, said insulating layer comprising:
a plurality of channels facing the geopolymeric material layer and housing a plurality of pipes for the flow of a service fluid,
small vent channels fluidly connected to said channels.
10 . A panel consisting of the geopolymeric material according to claim 6 .