Fig. 21

Photo image of samples with different CaO: SiO2 ratios (1 = 1: 1.17, 2 = 1: 1.25, and 3 = 1: 1.45) fired at different temperatures.
Photo image of samples with different CaO: SiO2 ratios (1 = 1: 1.17, 2 = 1: 1.25, and 3 = 1: 1.45) fired at different temperatures.