1、This document has been approved for use by agen- cies of the Department of Defense and for listing in the DoD Index of Specifications and Standards. 306.1 -90 (Reapproved 2002) Standard Specification forcold Weather Concreting (306.1-90) Reported by AC1 Committee 306 Nicholas J. Carino, Chairman* Fr
2、ed Anderson* Peter Antonich George R. U. Burg Oleh B. Ciuk Douglas J. Haavik* Gilbert Haddad Jules Houde David A. Hunt Robert A. Kelsey Albert W. Knott Charles J. Korhonen William Perenchio* John M. Scanlon This Standard Specification gives requirements for cold weather con- creting. It includes col
3、d weather requirements for preparations prior to placement of concrete, and protection of concrete. Keywords: accelerating admixtures; cold weather; compressive strength; con- struction; curing; formwork; freezing; heating; insulation; maturity; protec- tion; temperature. FOREWORD F1. This foreword
4、is included for explanatory pur- poses only; it does not form a part of the Standard Specification AC1 306.1. F2. Standard Specifications AC1 306.1 is a Reference Standard which the Archtect/Engineer may cite in the Project Specifications for any building project, to- gether with supplementary requi
5、rements for the spe- cific project. F3. Each technical section of Standard Specification AC1 306.1 is written in the Three-Part Section Format of the Construction Specifications Institute, as adapted by AC1 and modified to AC1 requirements. The lan- guage is generally imperative and terse. F4. Check
6、lists do not form a part of Standard Spec- ification AC1 306.1. Checklists are to assist the Archi- tect/Engineer in properly choosing and specif$ng any necessary requirements for the Project Specifications. PREFACE TO SPECIFICATION CHECKLIST P1. Standard Specification AC1 306.1 is intended to be us
7、ed by reference or incorporation in its entirety in the Project Specifications. Individual sections, articles, or paragraphs shall not be copied into the Project Specifications, since tahg them out of context may change their meaning. *Task force for revision. Supercedes AC1 306.1-87. Revised by the
8、 Expedited Standardization Proce- dure, effective July 1, 1990. In 1990, the format was revised. The Foreword, Preface, and Specification Checklist were revised. Reference Standards were updated and the sections on Materials and Execution were rewritten and re- numbered. Michael Shydlowski Bmce A. S
9、uprenant J. Derle Thorpe Valery Tokar Lewis H. Tuthill* Harold B. Wenzel Arthur T. Winters P2. If sections or parts of Standard Specification AC1 306.1 are edited into project specifications or any other document, they shall not be referred to as AC1 Standards, since the Standard Specification has b
10、een altered. P3. Building codes set minimum requirements neces- sary to protect the public. This Standard Specifica- tion may stipulate requirements more restrictive than the minimum. Adjustments to the needs of a particular project shall be made by the Architect/Engineer by re- viewing each of the
11、items in the Specification Check- list and then including the Archtect/Engineers deci- sion on each item as a mandatory requirement in the Project Specifications. P4. These mandatory requirements designate the specific qualities, procedures, materials, and perfor- mance criteria for which alternativ
12、es are permitted or for which provisions were not made in the Standard Specification. Exceptions to the Standard Specifica- tion shall be made in the Project Specifications, if re- quired. P5. A statement such as the following will serve to make Standard Specification AC1 306.1 a part of the Project
13、 Specifications. Work on shall conform to all requirements of AC1 306.1, Standard Spec- ification for Cold Weather Concreting, published by the American Concrete Institute, Detroit, Michigan, except as modified by the requirements of these Contract Documents. P6. The Standard Specification Checklist
14、 identifies Architect/Engineer choices and alternatives. The checklist identifies the sections, parts, and articles of the Standard Specification and the action required by the Archtect/Engineer. Copyright 0 2002, American Concrete Institute. All rights reserved includ- ing rights of reproduction an
15、d use in any form or by any means, including the making of copies by any photo process or by any electronic or mechanical de- vice, printed or written or oral or recording for sound or visual reproduction or for use in any knowledge or retrieval system or device, unless permission in writing is obta
16、ined from the copyright proprietors. 306.1-1 306.1-2 AC1 STANDARD SPECIFICATION CHECKLIST M. MANDATORY REQUIREMENTS Section/Par/Article of AC1 306.1 Notes to the ArchitectEngineer 1.4 Reference standards 3.1 Preparation before concreting Review applicability of the cited references and take exceptio
17、n if required If the temperature of massive embedments, such as heavy steel de rails or channels and steel grate frames or ducts, is lower than 32 F, concrete cast around them will be gaged b freezing. IdentiSi in the Contract Documents massive embedments which must be at a temperature above Zeezing
18、 prior to placement of con- crete. A frozen subgrade can lead to freezing of newly-placed concrete or foundation settlement upon subse uent thawing of the subgrade. SpeciSi in the Contract Documents the depth to which frozen subgrade shojd be thawed prior to placement of concrete. Specify procedure
19、to verify that subgrade has been thawed to specified depth. 3.2.2 Protection temperature Speci the frequency for recording the temperature but do not use a frequency lower than twice per 24-hr pe- riod. 3.4.5 Protection for structural safety Indicate in the Contract Documents the concrete strength r
20、equired for each structural member before form re- moval or continued construction, or both. O. OPTIONAL REQUIREMENTS Section/Par/Article of AC1 306.1 Notes to the ArchitectEngineer 1.5.1 Detailed procedures Indicate in the Contract Documents whether submittal, review, and acceptance of procedure is
21、 required. Des- ignate degree of detail required in any submittal procedure. 3.3 Curing concrete Strength gain may not continue after removal of the protection because of rapid drying in regions where there are periods of cold, dry, wind weather. Therefore, under these conditions, consideration shou
22、ld be given to extending the protection peno1 in order to facilitate moist curing. Spec* the minimum protection temperature if different than Column 2 of Td ., .c.:. . : h4.* 1 B km p. sub. 9 -4, ., y . 3.1 - Preparation before concreting 3.2 - Concrete temperature 3.3 - Curing of concrete 3.4 - Pro
23、tection of concrete 1 -GENERAL 1.1 - Scope 1.1.1 This Standard Specification covers require- ments for cold weather concreting and protection of concrete fi-om freezing during the specified protection period. 1.1.2 The provision of this Standard Specification shall govern unless otherwise specified
24、in the Contract Documents. 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
25、 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 high
26、est 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 protec
27、tion 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
28、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. Project drawings -The drawings, which along with the Project Specifications, complete the descripti
29、ve in- formation for constructing the Work required or re- ferred to in the Contract Documents. Project specifications - The written documents which specifj requirements for a project in accordance with the service parameters and other specific criteria established by the Owner. Protection period -
30、The required time during which the concrete is maintained at or above a specific tem- perature in order to prevent freezing of the concrete or to ensure the necessary strength development for struc- tural safety. Reference standards - Standards of a technical so- ciety, organization, or association,
31、 including the codes of local or state authorities, which are referenced in the Contract Documents. Required - Required by this Specification or the Contract Documents. Submitted - Submitted to the ArchitectEngineer for review. Work - The entire construction or separately iden- tifiable parts thereo
32、f which are required to be fur- nished under the Contract Documents. Work is the result of performing services, furnishmg labor, and furnishing and incorporating materials and equipment into the construction, all as required by the Contract Documents. 1.3 - Reference organizations ACI: American Conc
33、rete Institute P.O. Box 19150 Detroit, MI 48219 ASTM: American Society for Testing and Materials 1916 Race Street Philadelphia, PA 19 103 1.4 - Reference standards 1.4.1 ACI Standards 301-89 Specifications for Structural Concrete for Buildings Standard Method of Making and Curing Concrete Test Speci
34、mens in the Field C 150-86 Standard Specification for Portland Cement C 494-86 Standard Specification for Chemical Admixtures for Concrete C 803-82 Standard Test Method for Penetration Resistance of Hardened Concrete 1.4.2 ASTM Standards C 31-88 306.1-4 AC1 STANDARD C 873-85 Standard Test Method for
35、 Compressive Strength of Concrete Cylinders Cast in Place in Cylindncal Molds C 900-87 Standard Test Method for Pullout Strength of Hard- ened Concrete 1.5 - Submittal of procedures 1.5.1 Detailed procedures - If required, submit de- tailed procedures for the production, transportation, placement, p
36、rotection, curing, and temperature moni- toring of concrete during cold weather. In the submit- tal, include procedures to be implemented upon abrupt changes in weather conditions or equipment failures. Do not begin cold weather concreting until these pro- cedures have been reviewed and accepted. 2-
37、 MATERIALS 2.1 Scheduling protection materials All materials and equipment required for protection shall be available at the project site before cold weather concreting. 2.2 - Concrete Concrete for slabs and other flatwork exposed to cycles of freezing and thawing in a wet condition dur- ing the con
38、struction period shall be air entrained as specified in AC1 30 1 even though the concrete may not be exposed to freezing in service. 3 - EXECUTION 3.1 - Preparation before concreting Remove all snow, ice, and fi-ost fi-om the surfaces, including reinforcement, against which the concrete is to be pla
39、ced. Before beginning concrete placement, thaw the subgrade to the depth specified in the Con- tract Documents. Do not place concrete around mas- sive embedments identified in the Contract Documents unless such embedments are at a temperature above freezing. 3.2 - Concrete temperature 3.2.1 Placemen
40、t temperature - The minimum tem- perature of concrete immediately after placement shall be as specified in Column 2 of Table 3.2.1. The tem- perature of concrete as placed shall not exceed the val- ues shown in Column 2 of Table 3.2.1 by more than 20 F. Table 3.2.1 - Concrete temperature (1) Least d
41、imension of section, in. Less than 12 12 to less than 36 36 to 72 Greater than 72 55 50 50 45 40 20 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
42、 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 e
43、ach 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 u
44、ntil the surface temperature of the concrete is with 20 F of the ambient or surrounding tempera- tures. When the surface temperature of the concrete is with 20 F of the ambient or surrounding tempera- ture, all protection may be removed. .,-, 3.3 - Curing of concrete Prevent concrete fi-om drying du
45、ring the required curing period. If water curing is used, terminate use at least 24 hr before any anticipated exposure of the con- crete to freezing temperatures. 3.4 - Protection of concrete 3.4.1 Combustion heaters - Vent flue gases fi-om combustion heating units to the outside of the enclo- sure.
46、 3.4.2 Overheating and drying - Place and direct heaters and ducts to avoid areas of overheating or drying of the concrete surface. 3.4.3 Maximum air temperature - During the pro- tection period, do not expose the concrete surface to air having a temperature more than 20 F above the values shown in
47、Column 2 of Table 3.2.1, unless higher values are required by an accepted curing method. 3.4.4 Protection against freezing - Cure and protect concrete against damage fi-om freezing for a minimum period of 3 days, unless otherwise specified. Maintain the surface temperature of the concrete during tha
48、t pe- riod in accordance with Column 2 of Table 3.2. l, un- less otherwise specified. The protection period may be reduced to 2 days if use of one or more of the follow- ing to alter the concrete mixture is accepted: Type III portland cement meeting the require- A strength accelerating admixture mee
49、ting the re- 100 lb/yd3 of additional cement ments of ASTM C 150 quirements of ASTM C 494 During periods not defmed as cold weather, but when freezing temperatures may occur, protect concrete sur- faces against freezing for the first 24 hr after placing. 3.4.5 Protection for structural safety - If the con- crete strength is required for structural safety, extend COLD WEATHER CONCRENG SPECIFICATION 3 06.1-5 in. Ib/yd psi temperature, “F temperature interval, “F the duration of the protection period to ensure the nec- essary strength development. The strength required for formwork re
