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Chemically bonded ceramic/cementitious materials of alkali activated metakaolin processed by cold pressing
Highlights Chemically bonded ceramics of metakaolin with various alkalis were investigated. Semi-dry pastes were uniaxially cold pressed and then cured up to 300 °C for up to 3 h. Strengths up to 19 MPa (Flexural) and 50 MPa (compressive) were stable up to 1 year. The main reaction product were a gel N-A-S-H, Na-faujasite and silica gel. Ceramic-like materials with high strength were obtained in short curing times.
Abstract The strength, reaction products and microstructure of chemically bonded ceramic/cementitious materials of metakaolin activated with various alkalis, at 12–16% wt. R2O (R = Na or K), were investigated for one year. Pastes of low water:solids ratio were uniaxially cold-pressed and cured at 100–300 °C for 1–3 h. The Taguchi method was used for the experimental design. The flexural and compressive strength reached up to 19 and 50 MPa, respectively. The Optimum conditions to maximize the compressive and flexural strength were the use of liquid sodium silicate, 12%Na2O and curing at 300 °C for 1 h. XRD, SEM and NMR showed the formation crystalline Na-faujasite, silica gel and N-A-S-H type gel as reaction products identified by the presence of Q4(4Al), Q4(3Al) and Q4(2Al) sites. The processing is suitable to obtain useful stable alkali activated ceramic-like materials with high strength in short curing times.
Chemically bonded ceramic/cementitious materials of alkali activated metakaolin processed by cold pressing
Highlights Chemically bonded ceramics of metakaolin with various alkalis were investigated. Semi-dry pastes were uniaxially cold pressed and then cured up to 300 °C for up to 3 h. Strengths up to 19 MPa (Flexural) and 50 MPa (compressive) were stable up to 1 year. The main reaction product were a gel N-A-S-H, Na-faujasite and silica gel. Ceramic-like materials with high strength were obtained in short curing times.
Abstract The strength, reaction products and microstructure of chemically bonded ceramic/cementitious materials of metakaolin activated with various alkalis, at 12–16% wt. R2O (R = Na or K), were investigated for one year. Pastes of low water:solids ratio were uniaxially cold-pressed and cured at 100–300 °C for 1–3 h. The Taguchi method was used for the experimental design. The flexural and compressive strength reached up to 19 and 50 MPa, respectively. The Optimum conditions to maximize the compressive and flexural strength were the use of liquid sodium silicate, 12%Na2O and curing at 300 °C for 1 h. XRD, SEM and NMR showed the formation crystalline Na-faujasite, silica gel and N-A-S-H type gel as reaction products identified by the presence of Q4(4Al), Q4(3Al) and Q4(2Al) sites. The processing is suitable to obtain useful stable alkali activated ceramic-like materials with high strength in short curing times.
Chemically bonded ceramic/cementitious materials of alkali activated metakaolin processed by cold pressing
Ortega-Zavala, D.E. (author) / Burciaga-Díaz, O. (author) / Escalante-García, J.I. (author)
2020-10-16
Article (Journal)
Electronic Resource
English
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