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II 11'. (2) Ensure that the mix is at least 3 yd [2.3 m3] and is mixed in a mixer truck. (3) After initial mixing, determine the slump, concrete temperature, ambient temperature and air content. Ensure that the concrete properties are within the required specification target limits. (4) Mix the concrete intermittently for 30 seconds every five minutes at the mixing speed of the mixer. (5) Determine slump, concrete temperature, ambient temperature and air content at 30 minute intervals until the slump is 4 inches [100 mm] or less. Remix the mix for one minute at the mixing speed of the mixer before these tests are run. (6) Begin all elapsed times when water is initially introduced into the MIX. (7) Ensure that the concrete maintains a slump of at least 4 inches [100 mm] for the anticipated elapsed time. (8) Obtain the Engineer's approval of slump loss test results in terms of elapsed time before concrete placements. 346 -3.3 Mass Concrete: When mass concrete is designated in the Contract Documents, provide an analysis of the anticipated thermal developments in the mass concrete elements for all expected project temperature ranges using the selected mix design, casting procedures, and materials. Use a Specialty Engineer competent in the design and temperature control of concrete in mass elements. The specialty Engineer will follow the procedure outlined in Section 207 of the ACI Manual of Concrete Practice to formulate, implement, administer and monitor a temperature control plan, making adjustments as necessary to ensure compliance with the Contract Documents. The Specialty Engineer will select the concrete design mix proportions that will generate the lowest maximum temperatures possible to ensure the 35 °F temperature differential is not exceeded. Describe the measures and procedures intended for use to maintain a temperature differential of 35 °F [20 °C] or less between the interior core center and exterior surface(s) of the designated mass concrete elements during curing. Submit both the mass concrete mix design and the proposed mass concrete plan to monitor and control the temperature differential to the Engineer for acceptance. Provide temperature monitoring devices to record temperature development between the interior core center and exterior surface(s) of the elements in accordance with the accepted mass concrete plan. The Specialty Engineer, or a qualified technician employed by the Specialty Engineer, must personally inspect and approve the installation of monitoring devices and verify that the process for recording temperature readings is effective for the first placement of each size and type mass component. Submit to the Engineer for approval the qualification of all technicians employed to inspect or monitor mass concrete placements. For placements other than the first, designate an employee(s) approved by the Specialty Engineer, as qualified to inspect monitoring device installation, to record temperature readings, to be in contact at all times with the Specialty Engineer if adjustments must be made as a result of the temperature differential being exceeded, and to immediately implement adjustments to temperature control measures as directed by the Specialty Engineer. Read the monitoring devices and record the readings at intervals no greater than 6 hours. The readings will begin when the mass concrete placement is complete and continue until the maximum temperature differential (not maximum temperature) is reached and a decreasing temperature differential is confirmed as defined in the temperature control March 2007 01000 -94 03- 4122.D ` ,