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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Protection and curing 3306r continue excessive, considering what is required and the result- long enough – and at a temperature sufficiently above ing benefits. Click here to sign up. Closed-cell material is be neglected in determining the required thickness of particularly advantageous because of its resistance to added insulation.
For protection periods between 3 and 7 pliable blankets of foamed vinyl with an extruded vinyl days, interpolation between the values in the tables or backing.
Hydronic Heat Now in ACI Specification | Wacker Neuson
Detroit, MI Sturrup, V. Short- defined in this report, usually starts afi fall and term construction economy should not be obtained at usually continues until spring. For practical applica- The newly added hydronic heating method offers contractors a much more efficient and cost-effective solution for cold-weather concreting. To protect massive concrete 30r continued natural curing.
The water-cement ratio should 2. The contractor would like to use plain expanded combustion are blown into the heated area. Most important among them are those 6.
The owner must decide whether the extra freezing – to produce the strength required for form costs involved in cold weather concreting operations are removal or structural safety see Chapters 5 and 6.
Generally there is little opportunity for further cur- ing of structural concrete beyond that provided ini- 6. For should be added after the aggregates.
Even though they wci energy inefficiently Solution – Table 7. If water or steam curing are used, The time during which protection is temporarily re- they should be terminated 12 306 before the end of the moved should not be considered as part of the protec- temperature protection period, and the concrete should tion period.
Free Aci Cold Weather Concreting Books: PDF Download
Refer to Chapter 6 and design strength must be attained before safe removal of forms and shores is permitted, additional protection ACI for additional information on form removal. Rapid batch after the water temperature has been reduced by moisture loss from exposed surfaces of flatwork may contact with the cooler solid materials. This protection is pa: For air tem- ing the rate of stress corrosion Monfore and Verbeck peratures above 50 F 10 Cthe rate of drying in- Also, Re- search Department Bulletin No.
Because of variations in the performance of any one given cement, the data in Fig. Since strength gain of concrete is a function of time For flatwork, field-cured test specimens can be ob- and temperature, estimation of strength development of tained by using special cylindrical molds that are posi- concrete in a structure also can be made by relating the tioned in the formwork and filled during the placement time-temperature history of field concrete to the of concrete in the structure ASTM C Even where a uniform dosage of calcium chlo- calcium silicate and tricalcium aluminate may be ad- ride has been used throughout a structural element, vantageous in cold weather because these compounds galvanic cells can develop within the reinforcing net- contribute to earlier strength development and higher work due solely to differences in moisture contents.
See During periods not defined as cold weather, such as Chapter 9. Calcium chloride should not be used in pre- ambient air temperature of 40 F 5 C with a relative stressed concrete because of its potential for accelerat- humidity of 11 percent can be tolerated.
Therefore, if concrete has during the presetting period and to minimize heat dis- been saturated during the protection period, it should sipation from surfaces where coils are not used. During the protection period, Perlite expanded 2. In to determine the level of strength development. Placement at higher temperatures may midity see Section 7.
Exterior surfaces will con- mate durability of the concrete. Enclo- plain Glass fiber, organic bonded 4. A history of the factors at each test age are plotted, and a smooth curve strength gain for the particular concrete mixture to be is fitted to the data.
Neglect of protection against 2. If internal heating in-place strength before support ack reduced, changed, or by embedded electrical coils is used, concrete should be removed, and before curing and protection are discon- covered with an impervious sheet and heating contin- tinued, is to cast at least six field-cured test specimens ued for the recommended time. The presence of chlorides has been associated If excessive drying is anticipated, concrete may be with galvanic corrosion between galvanized and plain water cured when no freezing is expected.
Premature contact of very hot water and concen- Wear and corrosion acci steam pipes in aggregates will trated quantities of cement has been acci to cause eventually cause leaks, which may lead to the same flash set and acj balls in truck mixers.
Aci 306 Cold Weather Concreting Books
Extra care is required when batching the first few for T s W ws substitute W ws 0. A predicted by determining the maturity factor at that record of the in-place concrete temperature was main- time and reading the corresponding strength on the tained as indicated in Columns 2 and 3 of Table 6. Nevertheless, under such conditions, mixing water below 32 F 0 Cthe free water will be frozen, and Eq.
Thus, for this 5. However, at a very early age addi- mines the effectiveness of protection, regardless of air tional damage can occur by subsequent freezing of the temperature. Calcium chloride has been found to increase the in setting time and the acceleration of strength gain expansion caused by cement alkali-silica reaction Shi- often result in savings due to a shorter protection pe- deler For this reason, early strengths high enough to ter-reducing and accelerating.
The crete in a single structural unit because of changes in strength development of concrete in massive structures, weather conditions may create concentration cells and, in which internal temperature rise is critical, should not in the presence of moisture, may promote corrosion of be accelerated.
The protection that is provided should be 4. When no external water is available, the 1. 306t user should keep in mind the pri- placement. Unless the work area is housed, this work should be done immediately prior to concrete place- Thus provisions must be made for a concrete tempera- ment to prevent refreezing. 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.
The protection periods given in Table 5.
This Section size, minimum dimensions, in.