1001. 3(k) 1001. 3(k) than 20F. Do not place concrete upon frozen foundation material, in forms containing frost, around frosted reinforcement, or in pile shells surrounded by ice or frozen earth. For succeeding batches, place concrete in the forms within 30 minutes. Place concrete in horizontal layers no more than 15 inches in depth. Fill each part of the form by depositing the concrete as close to its final position as possible. Do not work or flow concrete along the forms from the point of deposit. Work the concrete without displacing the reinforcement. Place concrete so that the upper surface of the concrete is at the indicated elevation after it has been struck off and after initial shri nkage has taken place. Finish exposed concrete surfaces accurately and evenly, free from open and rough areas, and free from depressions and projections. In bridge seats and walls, place concrete to the required elevation. Strike off with a straightedge and float to the correct elevation. Do not add water or curing agent to the concrete surface to assist in finishing. Finish bearing areas of substructures, as specified in Section 1001.3(k) 9. In areas where reinforcement extends through a construction joint, do not place concrete adjacent to previously placed concrete until at least 24 hours has elapsed.
work shutdown, caused by the failure of the equipment in operation. Use an acceptable mechanical vibrator. Do not attach it to the forms or reinforcement. Use a vibrator capable of transmitting vibration to the concrete with a frequency of not less than 100 impulses per second. Determine the vibrator size by the reinforcement spacing. When sufficient concrete has been deposited, spade and manipulate it to fill the form. Apply the vibrator to the concrete, at intervals not exceeding 3 feet, immediately after the concrete has been deposited. Move the vibrator throughout the mass, completely working the concrete around the reinforcement and other embedded fixtures, and into the corners and angles of the forms. Correct any reinforcement displacement caused by the vibrator before continuing vibration. Move the vibrator slowly to preve nt segregation. Do not use vibrators to spread concrete. Remove and discard concrete segregated by the vibrating operation. Ensure that the vibrator does not penetrate or disturb partially hardened layers. Reinforcement in freshly placed concrete may be vibrated for short durations to ensure proper reinforcement embedment.
3.a General. When the depth of water in the foundation area is less than 1 inch, no adjustments to the specified class of