The most common strength test, compressive strength, is carried out on a 50 mm (2-inch) cement mortar test specimen. The test specimen is subjected to a compressive load (usually from a hydraulic machine) until failure. This loading sequence must take no less than 20 seconds and no more than 80 seconds. Table 12 shows ASTM C 150 compressive strength specifications.

• Table 12: ASTM C 150 Portland Cement Mortar Compressive Strength Specifications in MPa (psi)

Curing Time	Portland Cement Type
	I	IA	II	IIA	III	IIIA	IV	V
1 day	-	-	-	-	12.4 (1800)	10.0 (1450)	-	-
3 days	12.4 (1800)	10.0 (1450)	10.3 (1500)	8.3 (1200)	24.1 (3500)	19.3 (2800)	-	8.3 (1200)
7 day	19.3 (2800)	15.5 (2550)	17.2 (2500)	13.8 (2000)	-	-	6.9 (1000)	15.2 (2200)
28 days	-	-	-	-	-	-	17.2 (2500)	20.7 (3000)
Note: Type II and IIA requirements can be lowered if either an optional heat of hydration or chemical limit on the sum of C3S and C3A is specified

一、 Standard Test Methods

•  AASHTO T 106 and ASTM C 109: Compressive Strength of Hydraulic Cement Mortars (Using 50-mm or 2-in. Cube Specimens)
•  ASTM C 349: Compressive Strength of Hydraulic Cement Mortars (Using Portions of Prisms Broken in Flexure)