aci minimum concrete temperature

S min = 0.0018 (for f y = 60,000 psi). Mixture proportioning for mass concrete is discussed in ACI 211.1. �tj��%�L�R:)���a�w U��g�B�֏�'�l2}xљ-�A��~4�%�?���]�������0>�V�P ƫ0�z>&I�S��ɠ5��Wf�p�L%�� /'��X���:��qͼ�l�dP^�C O�������9�(�t�N���JGW|�'���.ݻ�g��l�3R�y�UO�d����Tf�2�Y����n��v=����=�Cm�#a !X+qY{�7iOc�R� • When placing high-early-strength concrete or concrete with approved accelerators the 50° The American Concrete Institute (ACI) specifies in ACI 306R-16 Guide to Cold Weather Concreting recommended concrete temperatures based on the air … endstream endobj startxref Note 2: For Lines 2-4, maximum temperature is minimum temperature in the table plus 15 °F (9 °C). Section 7.12.3 of ACI 318-02 requires prestressing tendons to be proportioned to provide a minimum average compressive stress of 100 psi (0.7 MPa) on gross concrete area. endstream endobj 67 0 obj <>stream H���Oo�@���)�H�j���W�"5�TTJ� 1H�+@41� 0 �:�I •  Maximum – Unless otherwise specified, 95 degrees. The loss of volume causes the concrete to shrink, Although there is some cost to all t… The minimum ratio of required reinforcement is; FOR SLABS: f min = 0.002 (for f y = 40,000 psi). Hot weather is defined as any combination is high ambient temperature, high concrete temperature, low relative humidity, and wind velocity. h�ԘooI�?�}�~�(�����V�0��8�;�]�chk`Xf����S=��Mt{���������U ދD�LH/�DHiD&�J�K ��ia<4�[-2+��"s"K.!��"�B�ߙP*5B&�P�� |y�p��6��h���xp��=+t�n�0��T��KѣN�}��a(������'ju�b�O�@����X��)�[B�3������TH�D���=��[��]��t�� k��o2*�;e��F�\�/U�e��΂�i���O�Ŕ�vWN_��U�5Pq!��I����+"hȡ��{ �'��A��z���@g�uK$��"�ρ`�b������V-�o覘x>�XJ�6�oh;� ��I�E�;�U�::�9�5�tq�kk�V�I��>�F�lR��q��F6���9X�U�k\l Some concrete specifications contain a maximum temperature for the freshly mixed concrete as delivered. •  Minimum – If 3 day average less than 40 degrees, concrete 40 to 55 degrees depending on concrete dimensions. "u�1� dk�L�&�J�"/G�x�'0���A*. Note 1: For Line 1, maximum placement temperature is minimum temperature in the table plus 20 °F (11 °C). The minimum reinforcement ratio is the lowest possible quantity of steel that should be embedded in structural concrete elements to prevent premature failure after losing the tensile strength. ��z�z>��OQ�� ���>#���������F��e�����٦�m���? The American Concrete Institute (ACI) specifies in ACI 306R-16 Guide to Cold Weather Concreting recommended concrete temperatures based on the air temperature. The objectives are to prevent damage from early-age freezing (when the concrete is still saturated), to make sure the concrete develops the needed strength, and to limit rapid temperature changes or large temperature differentials that cause cracking. Concrete international MAY 2014 47 below 32°F [0°C]).5 However, given the recommendations in ACI 306R-10,4 ACI 306.1-90,3 and ACI 301-10,2 the minimum concrete temperature as placed must be at least 40°F (5°C). When concrete is being placed below 5 degrees but is not below freezing point, concrete … H�\�[k�@�����/{K@�4i �д?�� For Horizontal Steel. As recommended in ACI 306R, the mixing temperature should not be more than 15 °F (8 °C) above the values in Lines 2, 3, and 4. %PDF-1.7 %���� f min = 0.0015. 108 0 obj <>stream American Concrete Institute (ACI) P.O. 1.2—History When concrete was first used in dams, the dams were relatively small and the concrete was mixed by hand. -Concrete temperature (2.3) The concrete temperature at the time of placement should not be lower than the values given in Table 3.1, also the concrete temperature should be maintained at the recommended placement temperature for the required protection period. R����$�5���ˢa�nw��n�����ۓ֫'=��lH�R6h���=�?ʑߑ���wRo&����>=�o�<3@5���i]6h^�׫�X>֘m��5�#�;@z�g � �����j��H㘗��ۨA�l�)�Iǻk֍*�ԯs�5��=���g��X���:��� k.-���� ��;a ��F�M��!�aU"���V����2�Y�u��2�d4���i�)t½�0:�e�L�������=(��Ҟ ��h����d�s̎�b���ヷ�q��%tQ\�'0 1597 0 obj <>/Filter/FlateDecode/ID[<2DB69072FEC33144A6F05B1E53F6C838><4C29B2CD1984B24C802BAD72EFF78C62>]/Index[1583 29]/Info 1582 0 R/Length 84/Prev 1512536/Root 1584 0 R/Size 1612/Type/XRef/W[1 3 1]>>stream FOR WALLS: For Vertical Steel. Typical values are between 80° and 95° F as measured by ASTM C 1064-86. h�b```g``*f`a`�`b@ !�+s|f`�as����v,��a��P�d���0% �-~(飤p:�N��������ALB��@�@ Pc`�� �ŀXlv kK��u�>�4)p�(����#�����)�ˑiXm����Qg`��H3� �b`���` ��3� To control cracks to a … 87 0 obj <>/Filter/FlateDecode/ID[<8599594788DAD647BF92DBB45F3C42EE><474F1AD6159296469D74E6DF036507F6>]/Index[63 46]/Info 62 0 R/Length 108/Prev 496811/Root 64 0 R/Size 109/Type/XRef/W[1 2 1]>>stream Since the ACI 306R-10 edition, cold weather concrete applies when the air temperature is below 40 degrees or is expected to be below 40 degrees during the protection period. Section Size, minimum dimension <12” 12 to 36” Line Air Temperature Minimum concrete temperature as placed and maintained 1 - 55°F 50°F Minimum concrete temperature as mixed for the indicated air temperature* 2 Above 30oF 60°F 55°F 3 0 to 30oF 65°F 60°F 4 Below 0oF 70°F 65°F 5 Maximum allowable gradual temperature drop in the first 24 hours after end of … ACI 306R-10 Table 5.1, Temperature of Concrete includes recommended concrete temperatures by the air temperature range and by the minimum dimensions of the concrete section size. ACI 301-10 specifies a maximum temperature of 95°F. (1800 mm) Air temperature Minimum concrete temperature as placed and maintained — 55 °F (13 °C) 50 °F (10 °C) 45 ° (7 °C) 40 F (5 °C) Minimum concrete temperature as mixed for indicated air temperature* l�V�}�l�G'��\M?��2��K~��[�Ěz5�2�/).���K�Q�����s�!oB�m�ڶM���ͷo����&�q;�I|�IM��G� 5=� The protection period is defined as being between one and four days for concrete with accelerators mixed in (Table 7.1 of ACI 306). (mm) < 12 in. 1583 0 obj <> endobj Standard Test Method for Temperature of Freshly Mixed Hydraulic – Cement Concrete . Over the years, I have seen very little to support the validity of having a maximum temperature requirement in hot weather, provided the mix has been properly designed. I'm not sure where the rule is located in ACI 318-14. 9oq�*M�S�O��; �*���GR���Ǚq�f��q4���w�U'XӚ�ҭ�ۊؙ.��Ҍ�m5��յ��5���@ףi�(�Y����`G���ݙ�Q�fk�������d����?t%3����q?z)���J,�m�c��vW���s�e�S����n}Y�-ͅ�. The maximum reinforcement ratio is the largest steel area that can be put into concrete members … K������1��rxF�$;��wR��`M�yÄw�j��w�!���c��d/�D�"����6D��kDK�c�e��U����Q�*f��M�ae����R�rN}�s�{9��!Ě�2��b��s���X�n8���^�k;X=�2|uٷ�`a̪�����]�We������:��f��ϔ��d���ڇ��|a$��C�7�~�߂� Q]�X����T�h���� ��- endstream endobj startxref h�bbd```b``����`�$X$D2ՂH�h�Y"���*��$c� ���"@�! endstream endobj 1587 0 obj <>stream hޜT[o� �+cO]�$m�LM��:)�sX��ؑM���� �������w.|��4AQ����/&�ĮQ[!D�FV`�1'D(b� What is Cold-Weather Concreting? %%EOF ACI 306R-16: Guide to Cold Weather Concreting Author: ACI Committee 306 Subject: This document guides specifiers, contractors, and concrete producers through the selection processes that identify methods for cold weather concreting. Concrete Joints • Construction Joints • Expansion Joints Qualified laboratory technicians shall perform all required laboratory tests. American Concrete Institute ACI 306 defines cold weather when the following conditions exist for three consecutive days: The average daily temperature falls below 40°F, and Air temperature does not rise above 50°F for more than half a day in any 24-hour period. 63 0 obj <> endobj ASTM C 1064 . � ��0}��9ȾE xĸ�4fĀ1J��5���k�bǫ�\�`E�4�ђ�M��a���&��pS=��Yx��V*B�P�,�~����g�w�4� �l�pE�TN�r1�b�y��X ႎ��{H�2��P�|i$�t �L#�N"�"��=p�nλ5���ٿ�� Minimum Concrete Cover: • Concrete Base=3 inches (4” COE) • Concrete Walls=2 inches (3” COE) • Stilling Basin=6” (COE) Temperature and Shrinkage Reinforcing ACI 318 for Grade 60 Steel: As=0.0018bh ACI 350R (use chart), but As(min.)=0.0024bh. Box 9094 Farmington Hills, Mich. 48333-9094 American Petroleum Institute (API) Production Department 211 N. Ervay, Suite 1700 Dallas, Tex. As water evaporates from wet concrete, the total volume of the concrete decreases. The temperature reinforcement shall not be less than ½ inch at nine 9 inch center to center. endstream endobj 1584 0 obj <>>>/MarkInfo<>/Metadata 112 0 R/Names 1598 0 R/Outlines 453 0 R/PageLabels 1578 0 R/Pages 1581 0 R/StructTreeRoot 490 0 R/Type/Catalog/ViewerPreferences<>>> endobj 1585 0 obj <>/ExtGState<>/Font<>/ProcSet[/PDF/Text/ImageC]/XObject<>>>/Rotate 0/StructParents 97/Tabs/S/Thumb 109 0 R/TrimBox[0.0 0.0 612.0 792.0]/Type/Page>> endobj 1586 0 obj <>stream Cold weather period, as defined by ACI Committee 306, is when one of the following conditions occur for three consecutive days: Average daily air temperature is less than 40 o F ��L��'��x8h�Z�^�ڞy6Y�P.�v����O�s0vz�e�ŦN���)�=⾑����P�^��?P��*��M��+S���NSW��7��4�i�W3]��.�e������]�zS��}��s���!�g�u)���R������6U�73�f endstream endobj 64 0 obj <>>> endobj 65 0 obj <>/ExtGState<>/Font<>/ProcSet[/PDF/Text]>>/Rotate 0/TrimBox[0.0 0.0 585.0 783.0]/Type/Page>> endobj 66 0 obj <>stream Placement temperatures should not be higher than these minimum values by more than 20 F (11 C). In addition to carefully monitoring the temperature of concrete, formwork, reinforcing steel, subbase, subgrade and any other items associated with placement, the surfaces upon which concrete will be placed on should be above 32°F … Previous versions specified a maximum concrete temperature of 90°F. We use this provision for lift station slabs that can often be 3ft+ thick. ACI 306.1-90 Concrete temperatures Minimum concrete temps during the protection period are shown in column (2) Temps of concrete as placed shall not exceed the Column (2) by more than 20°F. ACI 301 has always contained limits on the minimum and maximum temperatures of delivered concrete for both hot and cold weather concrete applications. (300-900 mm) 36-72 in. For concrete with aggregates less than 3 inches, the thermometer must remain in the fresh concrete sample a minimum of 5 minutes or until the temperature reading stabilizes. ACI also limits the rebar spacing of beams and one-way slabs as a function of the steel stress under service loads (fs) in Section 10.6.4. ACI 318 indicates a minimum reinforcement of 0.0018 to control shrinkage and temperature effects. Therefore, regulating the temperature of concrete in cold weather is essential to its proper strength development. Concrete Temperature: ACI 301-16 • Mass concrete temperature must be monitored • Place 1 sensor and a backup at: 1) The center of the largest portion of placement 2) 2 in. � c*3�$������Ҍ�7����M�2&20��m>�8����z�]���A�Q\���M�T��d`a��^��{)i�&�2LWl>�s�m1g"Vr$���4#���,�Ȁ $2H��ei�y�ҿ |Va �� ��ս��$N�in��@Z��m5��E3��y$��г�� 0 Nonetheless, ASTM C 1064-86 set a maximum limit between 26.7°C and 35°C. If you have a 3ft thick section, then you can just look at top 1ft and bottom 1ft individually for minimum T & S steel. The objective of the ACI 306 is to keep concrete warm, over 5 degrees Celsius, for the first 48 hours, where concrete strength development is critical. ��6�'Hs��i��|��u�S�k�â��N�g�Kݤ~�ԟ�!u�����z�M��R�H�� �(o9�:�4������U�/N The code requirements for prestressing tendons used for shrinkage and temperature reinforcement might provide a starting place. ACI 301 provides two recommended temperature limits: a) The maximum concrete temperature shall not exceed 160 degrees Fahrenheit during curing, and b) The maximum temperature differential between the center and surface of placement shall not exceed 35 degrees Fahrenheit. h�b```a``�"W&11 �+P����i�B�CrOH���.���Ix���}���z*�@��+&O'%.�u�^�;G0��n�2�F� �aY����-R��ܻ�����t�W There are also other requirements in ACI 301-10 related to The minimum-reinforcement percentage, which is between 0.18 and 0.20%, does not normally control cracks to within generally acceptable design limits. (T or F) 2. 1905.6.2 Frequencyoftesting.The frequency of conduct-ing strength tests of concrete and the minimum number of tests shall be as specified in ACI 318, Section 5.6.2. ACI GRADE 1 FIELD TESTING CERTIFICATION PRACTICE TEST . The minimum amount and spacing of reinforcement to be used in structural floors, roof slabs, and walls for control of temperature and shrinkage cracking is given in ACI 318 or in ACI 350R. Design bar cutoffs. The temperature of concrete at the time of place- ment should always be near the minimum temperatures given in Chapter 3, Table 3.1. 1611 0 obj <>stream �T���%�26� i�}�$LK��ȫ��7ϳ����:��u�0�N�����d�$�f"��� ���c�e�9��j�E4 (300 mm) 12-36 in. The portland cement usually had to be aged to comply with a 5. ACI 350-06 Has the following table for minimum steel for sections thicker than 24 inches. (900-1800 mm) > 72 in. 4�c�bQ�{�����Cv�|�{6��ϖð��o^t�a^M����1�L�j��5,��K��-�0C�H���!����uC%|��v�x&7� Design temperature & shrinkage reinforcement. ��ib$�s�҈Z @�p��'��Q8��):>�'�1 ��"�~�jM\d}h�����a�;�3㇕���_#�j�7{�L��K��I� � b���4 �q�LLqf��܌d�J��g���?���.�ʴZ�L(�h&�z� b�$Jy�} ���v;�Q3�]�l����oY4�� �z)܅��/Fk��h�(��b)� ds�������[f�Q8��\���|���w����:z�&�uSBbܕ�3����-K�鈅� %PDF-1.5 %���� The minimum reinforcement ratio controls the cracking of concrete members. The minimum time period for which the concrete must be protected against freezing is as follows: • When placing regular concrete during "cold weather" conditions, the 50° f concrete temperature shall be maintained at least 3 days. “Cold weather concreting” is defined by the American Concrete Institute (ACI) 306: Guide to Cold Weather Concreting as the procedures relating to the placing, finishing, curing, and protection of concrete during cold weather.Monitoring temperature and meeting cold weather specifications is especially … One should take advantage of the opportunity provided by cold weather to place low- temperature concrete. 0 ¥��cD�����dޚ����G��(,�|ʞ�[���l��hrhHe�s��9M���@KPN%TќF�]�ŜPX1��� �,K,+ПaYШ�[B )]S�~�U�e4~X���c�0��%I=�Ԏ�{����B��>R9�LW4�ꏂ���X��B�TS�� �Y妜3�6��2K�q���_����[VN����5��2 ���dr�?B����P��tx���5�� ���w�w��׫�߉$�ݳH�*�F���W{��1�u�,+�Rd�����>_�l*In*)�V�3��e���8�"�Z L�L��od\z3���@I��ڀKV In case of an isolated footing with a depth greater … f min = 0.0025. Concrete Temperature Limits ACI 301.5, ACI 301, and ASTM C94 set no temperature limit on fresh concrete in hot weather conditions if precautions are considered in proportioning, production, delivery, placing, and curing concrete. Concrete work can be accomplished during even the coldest weather as long as the appropriate precautions are taken. the temperature of the fresh concrete when preparing speci-mens for strength tests. h�bbd``b`f�@�i#�`���� B�$D�� �[�&�X'@�w ��HpG�� �/��� !�$�@:��dq&F�s u�4$�3�y` ] Cooling and insulating systems for mass concrete are addressed in ACI 207.4R. Concrete Temperature Requirements Section size minimum dimension, in. 4. The mixing water will therefore be well above %%EOF [&F�} �**��~�` 0� 0 from center of nearest exterior surface 3) Shaded location to monitor ambient temperature • Monitor temperatures hourly • Compare temperatures with limits 17 1. ^�f�,)��c}v��[��t��L�Լ7��SB���(].�8djW���YÂ�VMJ\�k�]x{C���o���G���J�*:���P�zA�t��)��epK���20�A �U��L&`fV�5�0�i 6S

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