Optimization and Hydration Mechanism of Composite Cementing Material for Paste Filling in Coal Mines

Table 7

Effects of additives on performances of composite cementing material.

Test number	Contents of additives (%)	Setting time (min)		Compressive strength (MPa)
		Initial	Final	8 h	16 h	1 d	3 d	7 d	28 d
J1	D09	42	64	4.2	18.2	29.3	39.7	44.5	52.7
J2	Li2CO3 (0.15)	21	32	6.1	23.5	26.7	30.2	34.4	40.5
J3	Li2CO3 (0.30)	18	27	8.4	25.4	24.1	27.6	32.7	38.4
J4	H2BO3 (0.15)	125	184	2.0	12.7	20.7	34.2	39.5	51.2
J5	H2BO3 (0.3)	324	348	1.2	10.4	18.6	32.1	38.8	50.7
J6	H2BO3 (0.3) + Li2CO3 (0.1)	152	182	5.8	24.6	28.7	32.2	36.4	39.3
J7	H2BO3 (0.3) + Na2SO4 (0.1)	182	185	5.8	22.8	34.2	46.5	49.7	58.4
J8	H2BO3 (0.3) + NaNO2 (0.1)	214	232	5.2	19.5	32.9	43.2	47.3	54.1