Browsing by Author "Erdogan, Sinan Turhan"

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Citation - WoS: 20
Citation - Scopus: 21
Effects of Clay Type and Component Fineness on the Hydration and Properties of Limestone Calcined Clay Cement
(Springer, 2024) Atasever, Muhammet; Erdogan, Sinan Turhan
Limestone calcined clay cement (LC3) is emerging as an alternative to Portland cement, offering economic advantages, reduced CO2 emissions, and mechanical properties on par with Portland cement. Central to the effective utilization of LC3 is understanding how the fineness of its components affects its performance. The current study investigates limestone calcined clay cement mixtures composed of kaolinite, illite, and montmorillonite calcined clays and limestone at two levels of fineness. Strengths of mortar cubes were tested at 1, 3, 7, and 28 d and statistical analysis was performed with a 95% confidence level. Additionally, LC3 pastes were analyzed using x-ray diffraction, mercury intrusion porosimetry, scanning electron microscopy, and isothermal calorimetry. The fineness of the calcined clay along with the fineness of limestone is found to be statistically significant for 28-d strength in LC3 mortars made with kaolinitic and montmorillonite calcined clays. All hydrated blends had a hemicarboaluminate phase, whose intensity was related to the fineness of the calcined clay, and the monocarboaluminate phase formation was found to be dependent on both the fineness and type of calcined clay. Porosimetry revealed that LC3 pastes with illite clay have larger threshold pore diameters than those with kaolinite clay. LC3 pastes containing kaolinite have denser microstructures due to C-S-H and hemicarboaluminate formation. Pastes produced with coarse calcined clay and coarse limestone led to a broader, weaker heat development peak and lower normalized cumulative heat. LC3 with kaolinitic clay has the highest normalized cumulative heat, while that with montmorillonite calcined clay has the lowest.
Citation - WoS: 3
Citation - Scopus: 3
Characterization of Limestone Calcined Clay Cement Made With Calcium Sulfoaluminate Clinker
(Springer int Publ Ag, 2024) Atasever, Muhammet; Erdogan, Sinan Turhan
This study concentrated on producing limestone calcined clay calcium sulfoaluminate cement by replacing portland cement in limestone calcined clay cement with calcium sulfoaluminate cement, with the goal of increasing the early strength of limestone calcined clay cement. The mineralogy and microstructures of hydrating pastes were investigated using x-ray diffraction and scanning electron microscopy. Heat evolution was studied using isothermal calorimetry. Strength development and workability were assessed on mortar samples. The 1 day strengths of limestone calcined clay calcium sulfoaluminate cement samples exceeded those of limestone calcined clay cement by similar to 30-80%, though its strength gain slows significantly after 1 day due to the lack of calcium silicates, affecting pH and clay dissolution. Despite this, the strength development of limestone calcined clay calcium sulfoaluminate cement, when adjusted for CO2 emissions, is comparable to limestone calcined clay cement. Additionally, limestone calcined clay calcium sulfoaluminate cement provides a 10-15% higher flow and exhibits a lower heat of hydration beyond 12 h, while maintaining a production cost similar to that of limestone calcined clay cement.