1.1 This test method covers the determination of freshly mixed unit weight and the air-dry (in-service) unit weight for structural lightweight concrete. 1.2 This test method determines directly the unit weight of freshly mixed lightweight concrete for placement control and the air-dry weight at the age of 28 days for design control. A method to determine equilibrium air-dry unit weight directly is included. Note 1-An approximate method for calculating the 28 day air-dry unit weight, the equilibrium air-dry unit weight, and a formula for estimating the oven-dry unit weight of lightweight concrete are provided in Section 9. The formula for estimating the oven dry unit weight is modified to estimate the equilibrium air-dry unit weight. 1.3 The values stated in inch-pound units are to be regarded as the standard. The values given in parentheses are provided for information only. 1.4 This standard does not purport to address all of the safety problems, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.