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proven that the curing compound will not prevent bond,or unless positive measures are <br /> taken to remove it completely from areas to receive bonded applications. <br /> Moisture loss from surfaces placed against wooden forms or metal forms exposed to <br /> heating by the sun shall be minimized by keeping the forms wet until they can be safely <br /> removed. After form removal,the concrete shall be cured until the end of the curing time <br /> by one of the previously described curing methods. <br /> Curing shall be continued for at least 7 days in the case of all concrete except high-early <br /> strength concrete for which the period shall be at least 3 days. Alternatively,if tests are <br /> made of cylinders kept adjacent to the structure and cured by the same methods,moisture <br /> retention measures may be terminated when the average compressive strength has <br /> reached 70%of the specified concrete strength. <br /> B. Cold Weather <br /> When the mean daily outdoor temperature is less than 40'F,the temperature of the concrete shall <br /> be maintained between 50 and 700 for the required curing period. When necessary,arrangements <br /> for heating,covering,insulation,or housing the concrete work shall be made in advance of <br /> placement and shall be adequate to maintain the required temperature without injury due to <br /> concentration of heat. Combustion heaters shall not be used during the first 24 hours unless <br /> precautions are taken to prevent exposure of the concrete to exhaust gases which contain carbon <br /> dioxide. <br /> C. Hot Weather <br /> When necessary,provision for windbreaks,shading,fog spraying,sprinkling,ponding,or wet <br /> covering with a light colored material shall be made in advance of placement,and such protective <br /> measures shall be taken as quickly as concrete hardening and finishing operations will allow. <br /> D. Rate of Temperature Change <br /> Changes in temperature of the air immediately adjacent to the concrete during and immediately <br /> following the curing period shall be kept as uniform as possible and shall not exceed 5°F in any 1 <br /> hour or 50'F in any 24 hour period. <br /> E. Protection from Mechanical Injury <br /> During the curing period,the concrete shall be protected from damaging mechanical disturbances, <br /> such as load stresses,heavy shock,and excessive vibration. All finished concrete surfaces shall be <br /> protected from damage by construction equipment,materials,or methods,by application of curing <br /> procedures,and by rain or running water. Self supporting structures shall not be loaded in such a <br /> way as to overstress the concrete. <br /> 3.05 REPAIR OF SURFACE DEFECTS <br /> Surface defects,including tie holes,unless otherwise specified by the Contract Documents,shall be <br /> repaired immediately after form removal. <br /> A. Repair of Defective Areas <br /> All honeycombed and other defective concrete shall be removed down to sound concrete. If <br /> chipping is necessary,the edges shall be perpendicular to the surface or slightly undercut. No <br /> feather edges will be permitted. The area to be patched and an area at least 6"wide surrounding it <br /> shall be dampened to prevent absorption of water from the patching mortar. A bonding grout shall <br /> be prepared using a mix of approximately 1 part cement to 1 part fine sand passing a No.30 mesh <br /> sieve,mixed to the consistency of thick cream,and then well brushed into the surface. <br /> 9/17 Section 03310-Page 7 of 8 <br />