Advances in Civil Engineering

Research Article

Crystalline Swelling Process of Mg-Exchanged Montmorillonite: Effect of External Environmental Solicitation

Table 2

Structural parameters used to reproduce experimental patterns of SWy-2-Mg complex as a function of RH along the first hydration-dehydration cycle.


	% RH	% of MLS	% of 0W/1W/2W/3W-	L.Th	nH₂O	ZH₂O	Z_Mg	M
				0W	0W	0W	0W
				1W	1W	1W	1W
				2W	2W	2W	2W
				3W	3W	3W	3W

Hydration	40 (start)	65	0/45/55/0–R0	—	—	—	—
		35	0/05/95/0–R0	12.30	2	09.60	09.60	8
				15.65	4	10.00/14.50	12.40
				—	—	—	—
	50	70	0/35/65/0–R1	—	—	—	—
		30	0/0/85/15–R0	12.30	2	09.70	09.70	8
				15.75	4	10.00/14.50	12.40
				18.00	6	10.60/14.80/16.20	14.80
	60	60	0/0/70/30–R0	—	—	—	—
		40	0/30/70/0–R1	12.40	2.5	09.80	09.80
				15.75	5	10.00/14.70	12.40	7
				18.00	6	10.60/14.80/16.20	14.80
	70	80	0/0/70/30–R0	—	—	—	—
		20	0/25/5/0–R1	12.65	2.5	09.80	09.80	8
				15.80	5.6	10.00/14.85	12.60
				18.00	6	10.60/14.70/16.40	14.70
	80	80	0/0/65/35–R1	—	—	—	—	11
		20	0/65/35/0–R1	12.65	3	10.40	09.60
				15.80	6	10.00/14.50	12.70
				18.40	6	10.60/14.50/16.80	16.80

Dehydration	70	70	0/0/70/30–R0	—	—	—	—
		30	0/35/65/0–R0	12.40	2.5	10.20	09.20	10
				15.75	6	10.00/14.90	12.60
				18.40	6	10.40/14.90/16.70	14.70
	60	60	0/0/80/20–R1	—	—	—	—
		35	0/45/55/0–R1	12.15	2.5	10.30	10.30	10
				15.50	5	09.50/14.70	12.50
				18.30	6	10.70/14.70/16.70	14.70
	50	50	0/0/80/20–R0	—	—	—	—	—
		50	0/45/55/0–R1	12.00	2.5	10.30	10.30	10
				15.20	4	09.60/14.50	12.40
				18.30	6	10.60/14.50/16.70	14.50
	40	58	0/0/82/18–R1	—	—	—	—
		42	0/45/55/0–R1	12.30	2.5	10.00	10.00	10
				14.95	4	09.70/14.90	12.60
				18.30	6	10.20/14.70/16.90	14.70
	30	58	0/0/90/10–R0	—	—	—	—
		42	0/45/55/0–R1	12.50	2	10.00	10.00	10
				14.95	3.2	10.30/14.50	12.60
				18.20	6	10.00/14.70/16.90	14.70
	20	40	35/65/0/0–R1	10.70	—	—	9.00	9
		37.80	0/25/75/0–R1	12.50	2	09.70	09.70
		22.20	0/80/20/0–R0	14.75	3.6	10.30/14.50	12.40
				—	—	—	—
	10	60	15/85/0/0–R0	10.20	—	09.00	9.00
		40	0/65/35/0–R0	12.00	1.5	09.70	09.70	7
				14.75	3.6	10.30/14.00	12.40
				—	—	—	—
Rehydration	20	78	0/75/25/0–R0	—	—	—	—
		22	0/35/65/0–R0	12.00	1.5	09.50	09.50	9
				15.00	3.6	10.30/14.00	12.50
				—	—	—	—
	30	65	0/75/25/0–R0	—	—	—	—	—
		35	0/60/40/0–R0	12.00	1.8	09.50	09.50	10
				15.30	4	10.30/14.00	12.50
				—	—	—	—
	40 (return)	58	0/30/70/0–R1	—	—	—	—
		42	0/55/45/0–R1	12.40	1.8	10.20	10.50	7
				15.80	4	11.00–14.60	12.20
			—	—	—	—

Note: 3W, 2W, 1W, and 0W are attributed to the layer hydration state. R: Reichweit (R)″factor. R0 and R1 describe the MLS with random interstratifications or with partial segregation, respectively. L.Th: layer thickness in Å. nH₂O: number of H₂O molecule per half unit cell. Z_H2O: position along axis of H₂O molecule. Z_Mg: position of exchangeable cations per half unit cell calculated along axis. M: average layer number per stacking. n_Mg: number of H₂O molecule per half unit cell fixed to 0.15, indicating full saturation of the cationic exchange capacity CEC of the minerals.