Expansion Mechanism and Properties of Magnesium Oxide Expansive Hydraulic Cement for Engineering Applications

Table 1

Chemical and physical requirements for MgO expansive agent [30].

Items			Requirements
			R (rapid type)	M (medium type)	S (slow type)
MgO mass content (%)		≥		80.0
Loss on ignition (%)		≤		4.0
Water content (%)		≤		0.3
Reaction time (s)			<100	≥100 and <200	≥200 and <300
Fineness	80 µm square hole sieve residue (%)	≤		5.0
	1.18 mm square hole sieve residue (%)	≤		0.5

Reaction time is the time required for completing the neutralization reaction between magnesium oxide expansive agent and citric acid solution with definitive concentration