ACI 306.1-90 Standard Specification forcold Weather Concreting.
1.2. – Definitions These defmitions are to assist in interpreting the pro- visions of this specification. Accepted – Accepted by or acceptable to the Archi- tecthgineer. ArchitedEngineer -The architect, engineer, archi- tectural firm, engineering firm, or architectural and en- gineering firm issuing Project Drawings and Specifica- tions, or administering the Work under the Contract Documents. Cold weather – A period when for more than three successive days the average daily outdoor temperature drops below 40 F. The average daily temperature is the average of the highest and lowest temperature during the period fi-om midnight to midnight. When tempera- tures above 50 F occur during more than half of any 24 hr duration, the period shall no longer be regarded as cold weather. Cold weather concreting – Operations concerning the placing, finishmg, curing, and protection of con- crete during cold weather. Contractor – The person, firm, or corporation with whom the Owner enters into an agreement for con- struction of the Work. Contract documents – Documents including the Project Drawings and Project Specifications covering the required Work. Day – A time period of 24 consecutive hours. Owner – The corporation, association, partnership, individual, or public body or authority with whom the Contractor enters into an agreement and for whom the Work is provided.
3.2.2 Protection temperature – Unless otherwise specified, the minimum temperature of concrete during the protection period shall be as shown in Column 2 of i ahie 3.2. i. Temperatures specified to be maintained during the protection period shall be those measured at the concrete surface, whether the surface is in contact with formwork, insulation, or air. Measure the temper- ature with a surface temperature measuring device hav- ing an accuracy of _t2 F. Measure the temperature of concrete in each placement at regular time intervals as specified in the Contract Documents. 3.2.3 Termination of protection – The maximum decrease in temperature measured at the surface of the concrete in a 24-hour period shall not exceed the values shown in Column 3 of Table 3.2.1. Do not exceed these limits until the surface temperature of the concrete is w i t h 20 F of the ambient or surrounding tempera- tures. When the surface temperature of the concrete is w i t h 20 F of the ambient or surrounding tempera- ture, all protection may be removed.
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