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A platform for research: civil engineering, architecture and urbanism
One-part pastes and mortars of CaO-Na2CO3 activated blast furnace slag: Microstructural evolution, cost and CO2 emissions
https://orcid.org/0000-0002-1766-3236
Highlights Blends of CaO-Na2CO3 are effective activators for one part slag alkaline cements. Handling solid CaO-Na2CO3 activators is safer than sodium silicates. No transitional carbonated phases delaying the reactivity and hardening are formed. Blended activators produce economical binders with low embodied CO2 emissions.
Abstract The mechanical properties and a thorough characterization of the reaction products were studied in one-part blast furnace slag (BFS) binders activated with 4, 6 and 8 % of a blend of CaO-Na2CO3 (with molar ratios of 1:1) in relation to the BFS. Pastes and mortars were cured for 24 h at 20 °C or 60 °C; with subsequent exposure at 20 °C up to 90 days. The compressive strength indicated that curing at 20 °C was beneficial for the advancement of the reactions; binders with 8 % CaO-Na2CO3 developed 45 MPa after 90 days, while the other regime reached 35 MPa. Mortars with aggregate:binder proportions of 2:1 and 3:1 developed 24 MPa and 21 MPa at 28 days, respectively. XRD, thermal analysis, SEM, FT-IR and 29Si and 27Al NMR evidenced the consolidation of microstructures with low porosity, formed by C-(A-)S-H-type gel, hydrotalcite phases and calcite; the later occurred by reaction of Ca2+ and CO3 2− ions supplied by the alkaline activator. The assessed binders are environmentally friendly and cost effective compared to a blended Portland cement (BPC) paste and mortar.
One-part pastes and mortars of CaO-Na2CO3 activated blast furnace slag: Microstructural evolution, cost and CO2 emissions
https://orcid.org/0000-0002-1766-3236
Highlights Blends of CaO-Na2CO3 are effective activators for one part slag alkaline cements. Handling solid CaO-Na2CO3 activators is safer than sodium silicates. No transitional carbonated phases delaying the reactivity and hardening are formed. Blended activators produce economical binders with low embodied CO2 emissions.
Abstract The mechanical properties and a thorough characterization of the reaction products were studied in one-part blast furnace slag (BFS) binders activated with 4, 6 and 8 % of a blend of CaO-Na2CO3 (with molar ratios of 1:1) in relation to the BFS. Pastes and mortars were cured for 24 h at 20 °C or 60 °C; with subsequent exposure at 20 °C up to 90 days. The compressive strength indicated that curing at 20 °C was beneficial for the advancement of the reactions; binders with 8 % CaO-Na2CO3 developed 45 MPa after 90 days, while the other regime reached 35 MPa. Mortars with aggregate:binder proportions of 2:1 and 3:1 developed 24 MPa and 21 MPa at 28 days, respectively. XRD, thermal analysis, SEM, FT-IR and 29Si and 27Al NMR evidenced the consolidation of microstructures with low porosity, formed by C-(A-)S-H-type gel, hydrotalcite phases and calcite; the later occurred by reaction of Ca2+ and CO3 2− ions supplied by the alkaline activator. The assessed binders are environmentally friendly and cost effective compared to a blended Portland cement (BPC) paste and mortar.
One-part pastes and mortars of CaO-Na2CO3 activated blast furnace slag: Microstructural evolution, cost and CO2 emissions
https://orcid.org/0000-0002-1766-3236
Highlights Blends of CaO-Na2CO3 are effective activators for one part slag alkaline cements. Handling solid CaO-Na2CO3 activators is safer than sodium silicates. No transitional carbonated phases delaying the reactivity and hardening are formed. Blended activators produce economical binders with low embodied CO2 emissions.
Abstract The mechanical properties and a thorough characterization of the reaction products were studied in one-part blast furnace slag (BFS) binders activated with 4, 6 and 8 % of a blend of CaO-Na2CO3 (with molar ratios of 1:1) in relation to the BFS. Pastes and mortars were cured for 24 h at 20 °C or 60 °C; with subsequent exposure at 20 °C up to 90 days. The compressive strength indicated that curing at 20 °C was beneficial for the advancement of the reactions; binders with 8 % CaO-Na2CO3 developed 45 MPa after 90 days, while the other regime reached 35 MPa. Mortars with aggregate:binder proportions of 2:1 and 3:1 developed 24 MPa and 21 MPa at 28 days, respectively. XRD, thermal analysis, SEM, FT-IR and 29Si and 27Al NMR evidenced the consolidation of microstructures with low porosity, formed by C-(A-)S-H-type gel, hydrotalcite phases and calcite; the later occurred by reaction of Ca2+ and CO3 2− ions supplied by the alkaline activator. The assessed binders are environmentally friendly and cost effective compared to a blended Portland cement (BPC) paste and mortar.
One-part pastes and mortars of CaO-Na2CO3 activated blast furnace slag: Microstructural evolution, cost and CO2 emissions
Burciaga-Díaz, O. (author) / Betancourt-Castillo, I.E. (author) / Montes-Escobedo, M.E. (author) / Escalante-García, J.I. (author)
2023-01-15
Article (Journal)
Electronic Resource
English
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