Effects of Fine Gangue on Strength, Resistivity, and Microscopic Properties of Cemented Coal Gangue Backfill for Coal Mining

Table 4

Active ion content at 3-day and 28-day curing times.

	Compound	Mg	Si	Fe	Al	Ca	K	Na
3 d; (mg/L)	20%	0.664	1.76	0.447	6.966	86.5	2.28	2.94
	30%	0.596	1.69	0.438	6.758	77.6	2.43	2.77
	40%	0.650	1.70	0.412	6.638	74.3	2.34	2.82
	50%	0.601	1.56	0.387	6.495	72.1	2.18	2.88
	60%	0.624	1.47	0.342	5.786	63.7	2.08	2.68
28 d; (mg/L)	20%	0.748	0.468	0.327	7.452	47.0	2.62	2.57
	30%	0.687	0.547	0.334	7.714	49.6	2.37	2.63
	40%	0.674	0.608	0.332	8.007	48.7	2.57	2.84
	50%	0.746	0.584	0.437	8.125	51.6	2.18	2.71
	60%	0.689	0.617	0.441	8.131	52.4	2.60	2.64