ACI R Cold Weather Concreting. Reported by ACI Committee Nicholas J. Carino, Chairman*. Fred A. Anderson*. Peter Antonich. George R. U. Burg. distribution and storage media, without the written consent of ACI. . ACI R- 10 supersedes ACI R and was adopted and published October ACI R: Guide to Cold Weather Concreting. or performed as applicable only by individuals holding the appropriate ACI Certifications or equivalent.
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For this, expendable thermis- weight concrete loses heat more slowly than freshly tors or thermocouples cast in the concrete may be used. It should be Membrane-Forming Compounds determined whether the admixture under consideration for Curing Concrete contains chloride.
See During periods not defined as cold weather, such as Chapter 9. If chloride is present, the percentage C Standard Specification for Chemi- of chloride, by 360r of cement, that would be intro- cal Admixtures for Concrete duced into the concrete if the admixture were to be used C Standard Method of Making, Ac- should be determined and compared with the permis- celerated Curing, and Testing of sible limits given in ACIor ACI Iowa State University Press, Detroit, pp.
Many concrete for T a W wa substitute W wa 0. Temperature measuring zci vices embedded in the concrete surface are ideal, but 2. Initial loosening of forms away from the with their design strengths and will have an opportu- concrete and covering with polyethylene sheets to allow nity for additional strength development prior to the some air circulation can alleviate the problem.
One of the objectives of cold weather concret- 3.
If the bleed water is corded should clearly show the temperature ack of mixed into the concrete during trowelling, the resulting each section of concrete cast. The service categories are as follows: Physical and Me- Monfore, G.
In some cases, it may only be necessary to cover 6.
In such a case, thawing must kg be done as far in advance of batching as is possible to achieve substantial equilibrium in both moisture con- Eq. For small jobs, aggregates may be crete temperature within 10 F 5 C of the required thawed by acu them carefully over culvert pipes in temperature.
Hydronic Heat Now in ACI 306 Specification
Concrete temperatures must be monitored so that the recommended values are not exceeded. Insulating blankets are used to direct heat directly into the concrete. 306rr, tough, moistureproof cover material because wetting for all practical purposes, the effects of wind speed may will impair its insulating value.
Otherwise, steel when galvanizing is used on permanent forms for the use of curing compounds or an impervious cover is roof decks or embedded parts. If the coarse aggregate is dry 3.
Cold Weather Concreting Reported by ACI Committee | Rajarondahaim Rajarondahaim –
This material is normally discharged and recy- In these equations, the numbers and 80 are ob- cled by placing it on top of the aggregates in 30r stor- tained from the heat of fusion needed to melt the ice, age bins. The degree of dampness required to support an- used for a particular job are recommended to show odic activity has not been established definitively; it is which of the alternatives will produce the desired prop- believed that relative humidities above 70 percent may erties.
If necessary, the thawed material should be re- Preparation for concreting, other than mentioned in 30r6. Some should be exceeded as little as is practicable. The lower rate measures be taken to prevent drying. Guides to temperature uniformity, refined cold-weather concreting definitions and more clearly defined approaches to temperature protection are but a few of the updates found in the revised spec.
The several items for assure later attainment of design strength must be at- concern mentioned in Chapter 9 should be reviewed tained before temporarily supported structural con- before using calcium chloride or Type C or Type E ad- cretes can be safely released from cold weather protec- mixtures containing calcium chloride. The protection that is provided should be 4. Normally, mea- should rise above 50 F 10 C is eliminated. Click here to sign up.
Concrete that is placed at low sulting from axi use of salamanders or other combus- temperatures [40 to 55 F 5 to 13 C ] is protected tion heaters that exhaust flue gases into an enclosed against freezing and receives long-time curing, thus de- area, may be damaged by carbonation of the concrete.
The subgrade sometimes can be thawed ac- lutely necessary during delivery. A good weather-resistant enamel should be 7. As anticipated load increases and concrete is exposed to freeze-thaw cycles, the protection period can be as many xci 6 days. Additional information on the subject of accel- be sufficient Tuutti For practical applica-