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Calcined illite-chlorite shale as supplementary cementing material: Thermal treatment, grinding, color and pozzolanic activity
https://orcid.org/0000-0003-4488-0014
Abstract The thermal transformation (100–1100 °C) of two shales containing illite-chlorite (I/Ch), feldspars and quartz from La Cabañita quarry (Olavarria, Argentine) was studied by TG-DTA, XRD and FTIR. It included dehydration; dehydroxylation (350–800 °C) and the structural collapse of illite (950 °C); while the neoformations were hematite and iron spinel. For rotary kiln production, the glass formation due to feldspars melting at 1100 °C was the upper temperature limit. For the calcination temperature range of 900–1100 °C, grindability increased when calcination temperature increased, but the specific surface area decreased. The high Fe-content caused a reddish color of particle surface, but their cores were black. The pozzolanicity test was satisfied at 7 days and strength activity index was 0.84–0.97 and 0.94–1.04 at 28 and 90 days, respectively. The addition of calcined shale did not affect the mortar flow and the hydration products assembly. Calcined I/Ch shale was a slow reactive pozzolan with good strength at 90 days.
Graphical abstract Display Omitted
Highlights Thermal transformation of two illite-chlorite shales was studied to obtain pozzolan. Calcination temperature range is determined by illite collapse and glassy formation. Grindability and specific surface area of pozzolan depend on calcination temperature. Compressive strength equivalent to PC is achieved at 90 days for 25% mass replacement. Both calcined shales have similar properties determining the robustness for industry.
Calcined illite-chlorite shale as supplementary cementing material: Thermal treatment, grinding, color and pozzolanic activity
https://orcid.org/0000-0003-4488-0014
Abstract The thermal transformation (100–1100 °C) of two shales containing illite-chlorite (I/Ch), feldspars and quartz from La Cabañita quarry (Olavarria, Argentine) was studied by TG-DTA, XRD and FTIR. It included dehydration; dehydroxylation (350–800 °C) and the structural collapse of illite (950 °C); while the neoformations were hematite and iron spinel. For rotary kiln production, the glass formation due to feldspars melting at 1100 °C was the upper temperature limit. For the calcination temperature range of 900–1100 °C, grindability increased when calcination temperature increased, but the specific surface area decreased. The high Fe-content caused a reddish color of particle surface, but their cores were black. The pozzolanicity test was satisfied at 7 days and strength activity index was 0.84–0.97 and 0.94–1.04 at 28 and 90 days, respectively. The addition of calcined shale did not affect the mortar flow and the hydration products assembly. Calcined I/Ch shale was a slow reactive pozzolan with good strength at 90 days.
Graphical abstract Display Omitted
Highlights Thermal transformation of two illite-chlorite shales was studied to obtain pozzolan. Calcination temperature range is determined by illite collapse and glassy formation. Grindability and specific surface area of pozzolan depend on calcination temperature. Compressive strength equivalent to PC is achieved at 90 days for 25% mass replacement. Both calcined shales have similar properties determining the robustness for industry.
Calcined illite-chlorite shale as supplementary cementing material: Thermal treatment, grinding, color and pozzolanic activity
https://orcid.org/0000-0003-4488-0014
Abstract The thermal transformation (100–1100 °C) of two shales containing illite-chlorite (I/Ch), feldspars and quartz from La Cabañita quarry (Olavarria, Argentine) was studied by TG-DTA, XRD and FTIR. It included dehydration; dehydroxylation (350–800 °C) and the structural collapse of illite (950 °C); while the neoformations were hematite and iron spinel. For rotary kiln production, the glass formation due to feldspars melting at 1100 °C was the upper temperature limit. For the calcination temperature range of 900–1100 °C, grindability increased when calcination temperature increased, but the specific surface area decreased. The high Fe-content caused a reddish color of particle surface, but their cores were black. The pozzolanicity test was satisfied at 7 days and strength activity index was 0.84–0.97 and 0.94–1.04 at 28 and 90 days, respectively. The addition of calcined shale did not affect the mortar flow and the hydration products assembly. Calcined I/Ch shale was a slow reactive pozzolan with good strength at 90 days.
Graphical abstract Display Omitted
Highlights Thermal transformation of two illite-chlorite shales was studied to obtain pozzolan. Calcination temperature range is determined by illite collapse and glassy formation. Grindability and specific surface area of pozzolan depend on calcination temperature. Compressive strength equivalent to PC is achieved at 90 days for 25% mass replacement. Both calcined shales have similar properties determining the robustness for industry.
Calcined illite-chlorite shale as supplementary cementing material: Thermal treatment, grinding, color and pozzolanic activity
Irassar, Edgardo F. (author) / Bonavetti, Viviana L. (author) / Castellano, C. Cristina (author) / Trezza, Monica A. (author) / Rahhal, Viviana F. (author) / Cordoba, Gisela (author) / Lemma, Roxana (author)
Applied Clay Science ; 179
2019-05-22
Article (Journal)
Electronic Resource
English
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