Aci 306R
Páginas: 48 (11768 palabras)
Publicado: 6 de mayo de 2012
This document has been approved for use by agencies of the Department of Defense and for listing in the DoD Index of Specifications and Standards.
ACI 306R-88
(Reapproved 2002)
Cold Weather Concreting
Reported by ACI Committee 306
Nicholas J. Carino, Chairman* Fred A. Anderson* Peter Antonich George R. U. Burg* Oleh B. Ciuk Douglas J. Haavik* Gilbert J. Haddad Don B. Hill Jules HoudeDavid A. Hunt Robert A. Kelsey Albert W. Knott William F. Perenchio John M. Scanlon* Michael L. Shydlowski* Bruce A. Suprenant Derle Thorpe* Valery Tokar* Harry H. Tormey Lewis H. Tuthill* Harold B. Wenzel
The general requirements for producing satisfactory concrete during cold weather are discussed, and methods for satisfying these requirements are described. One of the objectives of cold weatherconcreting practice is to provide protection of the concrete at early ages to prevent damage from freezing. For many structural concretes, protection considerably in excess of that required to prevent damage by early freezing is needed to assure development of adequate strength. The following items are discussed in the report: recommended temperature of concrete, temperature records, temperatureof materials, preparations prior to placement, duration of protection period, methods for determining in-place strength, form removal, protective insulating covers, heated enclosures, curing methods, and accelerating admixtures. References are included that provide supplementary data on the effects of curing temperature on concrete strength.
Keywords: accelerating admixtures; age; aggregates;calcium chloride; cold weather; compressive strength; concrete construction; concretes; curing; durability; form removal; formwork (construction); freeze-thaw durability; heating; in-place testing; insulation; materials handling; protection; subgrade preparation; temperature.
Chapter 3 - Temperature of concrete as mixed and placed and heating of materials, p. 306R-5
3.1 3.2 3.3 3.4 3.5 3.6 3.73.8 Placement temperature Mixing temperature Heating mixing water Heating aggregates Steam heating of aggregates Overheating of aggregates Calculation of mixture temperature Temperature loss during delivery
Chapter 4 - Preparation before concreting, p. 306R-7
4.1 4.2 4.3 4.4 Temperature of surfaces in contact with fresh concrete Metallic embedments Removal of snow and ice Condition of subgradeCONTENTS Chapter 1 - Introduction, p. 306R-1
1.1 1.2 1.3 1.4 1.5 Definition of cold weather Standard specification Objectives Principles Economy
Chapter 5 - Protection against freezing and protection for concrete not requiring construction supports, p. 306R-7
5.1 5.2 5.3 5.4 5.5 5.6 Protection to prevent early-age freezing Need for additional protection Length of protection period Strippingof forms Temperature drop after removal of protection Allowable temperature differential
Chapter 2 - General requirements, p. 306R-3
2.1 2.2 2.3 2.4 2.5 2.6 2.7 Planning Protection during fall and spring Concrete temperature Temperature records Heated enclosures Exposure to freezing and thawing Concrete slump
Chapter 6 - Protection for structural concrete requiring construction supports,p. 306R-9
6.1 - Introduction 6.2 - Tests of field-cured specimens 6.3 - In-place testing 6.4 - Maturity method 6.5 - Attainment of design strength 6.6 - Increasing early strength 6.7 - Cooling of concrete 6.8 - Estimating strength development 6.9 - Removal of forms and supports 6.10 - Requirements
*Task force member. This report supercedes ACI 306R-78 (Revised 1983). Copyright © 2002, AmericanConcrete Institute. All rights reserved including rights of reproduction and use in any form or by any means, including the making of copies by any photo process, or by any electronic or mechanical device. 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 obtained from the copyright...
ACI 306R-88
(Reapproved 2002)
Cold Weather Concreting
Reported by ACI Committee 306
Nicholas J. Carino, Chairman* Fred A. Anderson* Peter Antonich George R. U. Burg* Oleh B. Ciuk Douglas J. Haavik* Gilbert J. Haddad Don B. Hill Jules HoudeDavid A. Hunt Robert A. Kelsey Albert W. Knott William F. Perenchio John M. Scanlon* Michael L. Shydlowski* Bruce A. Suprenant Derle Thorpe* Valery Tokar* Harry H. Tormey Lewis H. Tuthill* Harold B. Wenzel
The general requirements for producing satisfactory concrete during cold weather are discussed, and methods for satisfying these requirements are described. One of the objectives of cold weatherconcreting practice is to provide protection of the concrete at early ages to prevent damage from freezing. For many structural concretes, protection considerably in excess of that required to prevent damage by early freezing is needed to assure development of adequate strength. The following items are discussed in the report: recommended temperature of concrete, temperature records, temperatureof materials, preparations prior to placement, duration of protection period, methods for determining in-place strength, form removal, protective insulating covers, heated enclosures, curing methods, and accelerating admixtures. References are included that provide supplementary data on the effects of curing temperature on concrete strength.
Keywords: accelerating admixtures; age; aggregates;calcium chloride; cold weather; compressive strength; concrete construction; concretes; curing; durability; form removal; formwork (construction); freeze-thaw durability; heating; in-place testing; insulation; materials handling; protection; subgrade preparation; temperature.
Chapter 3 - Temperature of concrete as mixed and placed and heating of materials, p. 306R-5
3.1 3.2 3.3 3.4 3.5 3.6 3.73.8 Placement temperature Mixing temperature Heating mixing water Heating aggregates Steam heating of aggregates Overheating of aggregates Calculation of mixture temperature Temperature loss during delivery
Chapter 4 - Preparation before concreting, p. 306R-7
4.1 4.2 4.3 4.4 Temperature of surfaces in contact with fresh concrete Metallic embedments Removal of snow and ice Condition of subgradeCONTENTS Chapter 1 - Introduction, p. 306R-1
1.1 1.2 1.3 1.4 1.5 Definition of cold weather Standard specification Objectives Principles Economy
Chapter 5 - Protection against freezing and protection for concrete not requiring construction supports, p. 306R-7
5.1 5.2 5.3 5.4 5.5 5.6 Protection to prevent early-age freezing Need for additional protection Length of protection period Strippingof forms Temperature drop after removal of protection Allowable temperature differential
Chapter 2 - General requirements, p. 306R-3
2.1 2.2 2.3 2.4 2.5 2.6 2.7 Planning Protection during fall and spring Concrete temperature Temperature records Heated enclosures Exposure to freezing and thawing Concrete slump
Chapter 6 - Protection for structural concrete requiring construction supports,p. 306R-9
6.1 - Introduction 6.2 - Tests of field-cured specimens 6.3 - In-place testing 6.4 - Maturity method 6.5 - Attainment of design strength 6.6 - Increasing early strength 6.7 - Cooling of concrete 6.8 - Estimating strength development 6.9 - Removal of forms and supports 6.10 - Requirements
*Task force member. This report supercedes ACI 306R-78 (Revised 1983). Copyright © 2002, AmericanConcrete Institute. All rights reserved including rights of reproduction and use in any form or by any means, including the making of copies by any photo process, or by any electronic or mechanical device. 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 obtained from the copyright...
Leer documento completo
Regístrate para leer el documento completo.