R Hot Weather Concreting. ACI R Concrete mixed, transported, and placed under conditions of high ambient temperature, low humidity, solar. The technical committees responsible for ACI committee reports and standards strive to avoid . Copies of ACI R, ACI , and ACI must be. of Institute standards does not constitute governmental endorsement of ACI or the ACI R·IO supersedes ACI R·99 and was adopted and puhlished.
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distribution and storage media, without the written consent of ACI. ACI R supersedes ACI R and was adopted and published October ACI R: Guide to Hot Weather Concreting. Secure PDF associated with mass concrete are treated more thoroughly in ACI R, R, and R. Hot weather, as defined by ACI R, is any combination of the following conditions that tends to impair the quality of freshly mixed or hardened concrete by.
Cornell II Antonio J. Guerra Darmawan Ludirdja Kenneth C. Tiffany D. Gene Daniel G. Terry Harris, Sr. Dan Ravina Louis R.
Valenzuela Kirk K. Deadrick Jerry S. Haught Robert J. This specification provides requirements for hot weather concreting that P3. Work on Project Title shall conform to all require- The document includes hot weather requirements for production ments of ACI Provisions governing a preplacement Concreting, published by the American Concrete Insti- conference, concrete mixture proportions, maximum allowable concrete tute, Farmington Hills, Michigan, except as modified temperature, measurement of the rate of surface evaporation, evaporation by these Contract Documents.
Specifications Institute, as adapted for ACI requirements. The language is imperative and terse. The Specification is written to the Contractor.
If the Contractor is and Submittals checklists following the Specification. ACI Specification Paragraphs into the Project Specification, because taking them out of context may change their meaning.
Provisions of this Specification shall West Conshohocken, PA govern, except where other provisions are specified in Phone: Contract Documents. Specimens hot weather concreting—operations concerning the C Test Method for Flexural Strength of preparation, production, delivery, placement, finishing, Concrete Using Simple Beam with protection, and curing of concrete during hot weather.
Do not place concrete against surfaces temperature of fresh concrete—the temperature that have free water. Customary or SI units concrete and air temperatures, relative humidity of the air, shall be regarded separately as standard.
Values stated in and the wind velocity have the capacity to evaporate water each system might not be exact equivalents; therefore, each from a free water surface at a rate that is equal to or greater system must be used independently of the other, without than 1.
Determine the evaporation rate of surface moisture by use of the Menzel Formula: 1. Customary units] placement, finishing, curing and protection of concrete during hot weather concreting. Obtain this ments and mix designs. The temperature of 1.
Multiply the saturation 1. Air temperature and relative humidity are to Mixed Concrete Producer. Continue to monitor site conditions at intervals of 30 minutes or less until specified curing procedures have been applied. Use equipment concreting commences. Include specific materials, manufacturer, testing using a concrete mixture similar to one known to have and type for hot weather concreting.
Frequency of temperature determination shall be in 70 0. During the minute 3. If necessary, move the laboratory mixer into an rotating the mixer continuously at a drum angle between 45 enclosed, heated and ventilated space, or use heated mixing and 75 degrees from horizontal. At the end of 50 minutes, water, or both, to achieve and maintain the proposed mix the concrete mixture at full mixing speed designated by maximum allowable concrete temperature.
For drum-type the manufacturer 8 to 20 rpm for 2 minutes.
During the minute period, the mixer shall 3. During the rest period, cover the mixer opening that its maximum temperature at discharge will not exceed with a non-absorbent material, such as plastic, to prevent the specified maximum allowable concrete temperature. At the end of 44 minutes, mix the concrete Acceptable production methods to reduce the temperature of mixture at full mixing speed designated by the manufacturer the concrete include: shading aggregate stockpiles, sprinkling 8 to 20 rpm for 2 minutes.
The substitution of other cooling methods will be of the or minute laboratory trial mixing period. If necessary, move the truck mixer into an enclosed, heated, and ventilated space to achieve a 3. The concrete mixture shall be held in the mixer for 90 minutes, 3. During 3. Use these materials and methods mixing speed designated by the manufacturer 6 to 18 rpm in accordance with ACI During mixing and agitation periods, the addi- tion of water, chemical admixture, or both, to adjust slump is 3.
As needed, check and adjust the slump of ACI C M. This Foreword is included for explanatory purposes the mixing period along with the other specified tests. Responsibilities for project participants proposed concrete mixture and all values obtained from past must be defined in the Project Specification. The ACI Spec- field experience or preconstruction testing. Test results shall ification cannot and does not address responsibilities for any be within the Project Specification ranges and tolerances.
The Submittals Checklist identifies Specifier choices Checklists assist the Specifier in selecting and speci- for information or data to be provided by the Contractor fying project requirements in the Project Specification. The Specifier shall make adjustments to the needs of a F7.
Recommended references—Documents and publications that are referenced in the Checklists of ACI Specification particular project by reviewing each of the items in the These references provide guidance to the checklists and including the items the Specifier selects as Specifier and are not considered to be part of ACI Specifi- mandatory requirements in the Project Specification.
AC1 certification programs identify craftsmen, technicians, and inspectors who have demonstrated their qualifications.
Stop the mixer and cover the batch with wet burlap; 4. Theodore, a Greek, one of the greatest of the cancers, who suggested throughout England, and enjoyed the 16 7 potential and heavy solution.
The total water initial water plus the remixing water can be expected to equal that required at the batch plant to give the required site slump; and job 5. Guide to Hot Weather Concreting: Chemical admixtures in affect the properties concrete as described the following.
Withoutabox Submit to Film Festivals. For most concrete, the maximum temperature reduction with is approximately ice 20 F 1 1 C. The affected area is then retroweled a to level finish. Site traffic should be coordinated for a quick turnaround of concrete mixertrucks. Therefore, the properties of 2. Arrangements should be made for readily available backup equipment. Concrete plant and delivery units should be in good operating condition.
Intermittent stoppage of deliveries due to equipment breakdown can be much more serious under hot weather conditions than in moderate weather. Concrete strengths are generally found to be substantially higher than those of comparable concrete without admixture and with the same cement content. High concrete temperatures, high wind speed, and low humidity, alone in or combination, cai rapid evaporation of surface water.
English Choose a language for shopping. The several volumes are arranged to group related material together and maybe purchased individually or in setS.
Please choose a product format. These methods and their effectiveness are discussed further.
Manyconcrete placements get off to a bad start because the concrete was ordered before the job was ready and slump control was lost at this most critical time.
To maximize amounts of ice or cold mixing axi should be well-drainedof free moisture, permitting a greater quantity of ice or cold mixing water to be used.
Procedures for keeping exposed surfaces from drying must be promptly commenced, with amplecoverage and continued withoutinterruption.