Study on Modification of Alkali-Free Liquid Accelerator of Mine-Used Wet-Mix Shotcrete

Table 6

Physical properties of concrete materials.

Concrete materials	Sizes	Bulk density (g/cm^3)	Fineness modulus	Elastic modulus (GPa)	Compressive strength
					3 d	28 d
Cement	≤60 μm	3.0	Qualified	—	29.8 MPa	55.8 MPa
Fine aggregate	≤3 mm	2.58	2.81	0.21	—
Coarse aggregate	4–12 mm	2.65	5.68	0.23	—