704.2(c) 704.3(c) of allowable mixing time.
• If using mixer or agitator trucks, agitate concrete for at least 20 revolutions immediately before placement. Do not use concrete that has exceeded 45 minutes without agitation.
• If wash water is used to clean the truck drum, completely discharge this wash water before the introduction of the succeeding batch.
• Do not allow concrete to come in contact with aluminum unless the aluminum is coated with an acceptable coating (delivery of concrete in an aluminum truck bed is allowed).
contract documents, are incidental.
704.3VOLUMETRIC MIXED CEMENT CONCRETE —
plant. Provide plant equipment, facilities, and a concrete technician(s) as specified in Section 704.1. Do not begin production until the mixing plant and all equipment and facilities necessary for performing the work have been inspected and accepted. Mixing plants may be truck mounted.
anchors, signposts , and similar miscellaneous structures requiring small quantities of concrete. If allowed by the District Executive in writing, volumetric mixing plants may also be used for pavement patching and structures. Approved plants may produce concrete for precast items.
volume in terms of mixed concrete, the operating speed, the plant auger mixing angle, and the plant weight - calibrated cement constant in terms of a revolution counter or other output indicator, all as r ated by the manufacturer.
bins and prevent contamination and intermixing of the fine and coarse aggregates during loading and transporting. Keep the cement bins free of moisture and contamination. Provides uitable means to carry water and additives and to incorporate the additives with the mixing water in the mix .
ingredients to the mixing unit. Equip each bin with an accurately controlled individual gate to form an orifice for volumetrically measuring the material drawn from the bin compartme nt. Do not charge aggregate bins more than 4 hours before mixing. Set the cement bin feeding mechanism to discharge a given volumetric weight equivalent of cement at a continuous and uniform rate during the concrete mixing operation. Coordinate the coarse and fine aggregat