Identification of the hydrates formed in cement paste in the presence of MSWI fly ash

To identify hydrates formed in cement paste in the presence of MSWI fly ash, XRD analyses were carried out.

Cement pastes with a water/cement (W/C) ratio of 0.5 and ash/cement ratios of 0 and 0.2 were prepared for the XRD analyses. The pastes were placed in two layers in 7 cm x 7 cm x 40 cm molds (60 impacts per layer) on the impact test bench. After placement, the molds were then kept in sealed bags. The cement pastes were removed from the molds after two days, then placed once again in sealed bags and kept at a temperature of 20 ºC. After curing for at least 28 d in the sealed bags, the central region of the samples was cut out (approximately 1 cm was removed from each surface of the test pieces). XRD was then carried out with the copper Ka line (l = 1.5406 Å). These tests were carried out at the Henry Longchambon Diffractometry Centre in Lyon. Table 1 shows the composition of the pastes.