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ASTM C 171. <br />1 1.2 MINIMUM CURING PERIODS <br />Basic Tvoe of Cement 50~ F - 70~ F 70a F - 100a F <br />Normal or Sulphate Resistant 7 days 5 days <br />11.3 PROTECTION <br />11.3.1 COLD WEATHER <br />When the mean daily temperature of the atmosphere is less <br />than forty degrees Fahrenheit (40a Fl, the temperature of <br />the concrete shall be maintained between fifty degrees <br />Fahrenheit (50~ F) and seventy degrees Fahrenheit (70~ F) <br />for the required curing period. When necessary, <br />arrangements for heating, covering, insulating or housing <br />shall be made in advance of placement and shall be <br />adequate to maintain the required temperature and moisture <br />conditions without injury due to the concentration of heat. <br />Detailed recommendations are given in "Recommended <br />Practice of Cold Weather Concreting" (ACI 306R). <br />11.3.2 HOT WEATHER <br />When the air temperature is expected to exceed ninety <br />degrees Fahrenheit (90~ F) within forty-eight (48) hours <br />after placement, all surfaces shall be protected from direct <br />sunlight and maintained in a moist condition for a minimum <br />period of forty-eight (481 hours. Detailed recommendations <br />are given in "Recommended Practice for Hot Weather <br />Concreting" (ACI 305R). <br />1 1.3.3 EXCESSIVE TEMPERATURE CHANGES <br />Changes in temperature of the concrete shall be as uniform <br />as possible and shall not exceed five degrees Fahrenheit 15~ <br />F) in any one 11) hour or twenty degrees Fahrenheit (20~ F) <br />in any twenty-four (24) hour period. <br />12 CONCRETE FINISHES <br />12.1 REPAIRING AND PATCHING SURFACES <br />Concrete surfaces shall be repaired immediately after form removal in <br />accordance with the following procedures below and with ACI 301 and <br />ACI 309.2R: <br />12.1.1 Holes left by tie rods shall be hammer packed with stiff, dry <br />mortar using the same materials as those in the concrete <br />except with a somewhat leaner mix. <br />12.1.2 Honeycombed areas shall be cut out to a depth at which <br />SPEC B -CONCRETE <br />PAGE i8 <br />