Specifications include, but are not limited to: A. Portland cement shall comply with ASTM C150 (Type I, II, or III). B. Fly ash shall NOT be used in storm tunnel applications. C. Water shall be free from deleterious substances. D. Foam used in the cellular concrete product shall be produced separately on the job site and be combined with discharged concrete slurry in-line. E. Admixtures for water reducing, retarding, accelerating, anti-washout and other specific properties may be used when specifically approved by the manufacturer of the pre-formed foam. F. Preformed cellular concrete shall have the following properties: 1. Wet-cast maximum density of 30 pcf 2. Minimum compressive strength of 130 psi 3. Material will require a slump sufficient for pumping and self-leveling of large void spaces or pipes.