Influence of production parameters on calcium sulfoaluminate cements


Canbek O., ERDOĞAN S. T.

CONSTRUCTION AND BUILDING MATERIALS, cilt.239, 2020 (SCI İndekslerine Giren Dergi) identifier identifier

Özet

The main appeal of calcium sulfoaluminate (C (S) over barA) cements is the possibility of reducing CO2 emissions. C (S) over barA clinkers can generally be produced at lower kiln temperatures and with lower limestone contents than required for portland cement clinker. However, it is important to assess the effects of various production parameters on the properties of C (S) over barA clinkers and cements. The influence of kiln maximum temperature, kiln retention time, and raw mixture proportioning on clinker properties, and those of water-to-cement ratio (W/C) and gypsum addition on cement hydration, were investigated. C (S) over barA clinkers were prepared in a laboratory furnace, with limestone, bauxite, and gypsum. Clinker and cement properties were explored with X-ray diffraction, isothermal calorimetry, thermogravimetric analysis, and scanning electron microscopy. Kiln temperatures as low as 1250 degrees C and retention times as low as 90 min. yielded satisfactory clinkers. Raw meal composition and calcination temperature have a greater effect on clinker phases than retention time. Hydration heat is affected mostly by raw meal composition. Hydration and strength gain were rapid until 3 d, after which they slowed down due to ettringite and AH(3) coating the clinkers particles. Mortars with W/C = 0.6, achieved using citric acid as a retarder, gained similar to 50 MPa strength at 28 d, 50-60% higher than mortars with W/C = 0.7. (C) 2019 Elsevier Ltd. All rights reserved.