CONCRETE CURING Sample Clauses
The CONCRETE CURING clause sets out the requirements and procedures for properly curing concrete after it has been placed. Typically, it specifies the methods to be used—such as maintaining moisture, covering with curing compounds, or using wet coverings—and the minimum duration for which curing must be maintained to ensure optimal strength and durability. This clause ensures that the concrete achieves its intended structural properties by preventing premature drying or cracking, thereby reducing the risk of defects and prolonging the lifespan of the finished structure.
CONCRETE CURING. A. Protect freshly placed concrete from premature drying and excessive cold or hot temperatures.
1. Comply with ACI 301 (ACI 301M) and ACI 306.1 for cold weather protection during curing.
2. Comply with ACI 301 (ACI 301M) and ACI 305.1 (ACI 305.1M) for hot- weather protection during curing.
3. Maintain moisture loss no more than 0.2 lb./sq. ft. x h (1 kg/sq. m x h), calculated in accordance with ACI 305.1, before and during finishing operations.
B. Curing Unformed Surfaces: Comply with ACI 308.1 (ACI 308.1M) as follows:
1. Begin curing immediately after finishing concrete.
CONCRETE CURING. Cure the precast units by any of the methods specified in Division 3, Section 4 of the PCI Manual for Quality Control for Plants and Production of Precast and Prestressed Concrete Products. Submit the curing method to be used in writing for approval before the start of fabrication.
1 Delay the application of steam within the enclosure for a period of five to six hours when the air temperature is 50º F or lower and delay for a period of three hours when the air temperature is 50º F or higher. 2 Wait a period from four to six hours if retarders are used, regardless of the air temperature. 3 Maintain the curing temperature at 145 ± 10º F for a period of 12 hours. Test two concrete test cylinders, similarly cured, after the curing procedure specified. Should the tests indicate that the precast units have not achieved a compressive strength of 5,000 pounds per square inch, cure the precast units further until the required strength is reached. Remove the forms after the precast units have achieved a compressive strength of 3,000 pounds per square inch. Perform one compressive strength test from the two concrete cylinders that are taken from each concrete truck or from each batch of concrete that is produced to determine the acceptance or failure of the concrete. Average together the two test results to obtain a single value representing the units. Concrete will be accepted if this averaged single value is equal to or greater than the class design strength as identified in Subsection 903.03, Table 903.03.06-3. Concrete will be accepted with a pay adjustment if the averaged single value is within the range from 1 to 500 pounds per square inch less than the class design strength for the specified concrete class, (i.e. for Class P concrete, this range will be between 5,000 and 5,500 pounds per square inch). The pay adjustment will be according to Section 903.03.05. Concrete will be rejected if the averaged single value is greater than the amount that is 500 pounds per square inch less than the class design strength for the specified concrete class. The RE may use testing results obtained from concrete cores or nondestructive testing before requiring any corrective action or removal and replacement of the concrete. All costs for coring and testing will not be paid.
CONCRETE CURING. Curing of the precast units shall be by any of the methods specified in Division 3, Section 4 of the PCI Manual for Quality Control for Plants and Production of Precast and Prestressed Concrete Products. The curing method to be used shall be submitted in writing for approval before the start of fabrication.
1. The applications of steam within the enclosure shall be delayed for a period of five to six hours when the air temperature is 50 ºF or lower and shall be delayed for a period of three hours when the air temperature is 50 ºF or higher.
2. If retarders are used, the waiting period shall be from four to six hours regardless of the air temperature.
3. The curing temperature shall be maintained at 145 ± 10 ºF for a period of 12 hours. Two concrete test cylinders, similarly cured, shall be tested after the curing procedure specified. Should the tests indicate that the precast units have not achieved a compressive strength of 5,000 pounds per square inch the precast units shall be cured further until the required strength is reached. Forms may be removed after the precast units have achieved a compressive strength of 3,000 pounds per square inch.
CONCRETE CURING. The Contractor shall not overspray chemical curing compounds and shall not allow runoff of curing compounds.
CONCRETE CURING. Protect freshly placed concrete from premature drying and excessive cold or hot temperatures.
CONCRETE CURING. A. In accordance with Section 03370.