|
90-7.01B CURING COMPOUND METHOD
<br /> • Surfaces of the concrete that are exposed to the air shall be sprayed uniformly with a curing compound.
<br /> • Curing compounds to be used shall be as follows:
<br /> 1. Pigmented curing compound conforming to the requirements in ASTM Designation: C 309,Type 2,Class B,except
<br /> the resin type shall be poly-alpha-methylstyrene.
<br /> 2. Pigmented curing compound conforming to the requirements in ASTM Designation: C 309,Type 2,Class B.
<br /> 3. Pigmented curing compound conforming to the requirements in ASTM Designation: C 309,Type 2,Class A.
<br /> 4. Nonpigmented curing compound conforming to the requirements in ASTM Designation: C 309,Type 1,Class B.
<br /> 5. Nonpigmented curing compound conforming to the requirements in ASTM Designation: C 309,Type 1,Class A.
<br /> 6. Nonpigmented curing compound with fugitive dye conforming to the requirements in ASTM Designation: C 309,
<br /> Type 1-D,Class A.
<br /> • The infrared scan for the dried vehicle from curing compound (1) shall match the infrared scan on file at the
<br /> Transportation Laboratory.
<br /> • The loss of water for each type of curing compound,when tested in conformance with the requirements in California
<br /> Test 534,shall not be more than 0.15-kg/m2 in 24 hours.
<br /> • The curing compound to be used will be specified elsewhere in these specifications or in the special provisions.
<br /> • If the use of curing compound is required or permitted elsewhere in these specifications or in the special provisions
<br /> and no specific kind is specified,any of the curing compounds listed above may be used.
<br /> • Curing compound shall be applied at a nominal rate of 3.7 m2/L,unless otherwise specified.
<br /> • At any point,the application rate shall be within±1.2 m2/L of the nominal rate specified,and the average application
<br /> rate shall be within t0.5 m/L of the nominal rate specified when tested in conformance with the requirements in California
<br /> Test 535. Runs, sags, thin areas, skips, or holidays in the applied curing compound shall be evidence that the application is
<br /> not satisfactory.
<br /> • Curing compounds shall be applied using power operated spray equipment. The power operated spraying
<br /> equipment shall be equipped with an operational pressure gage and a means of controlling the pressure. Hand spraying of
<br /> small and irregular areas that are not reasonably accessible to mechanical spraying equipment,in the opinion of the Engineer,
<br /> may be permitted.
<br /> • The curing compound shall be applied to the concrete following the surface finishing operation, immediately before
<br /> the moisture sheen disappears from the surface,but before any drying shrinkage or craze cracks begin to appear. In the event
<br /> of any drying or cracking of the surface, application of water with an atomizing nozzle as specified in Section 90-7.01A,
<br /> "Water Method," shall be started immediately and shall be continued until application of the compound is resumed or started;
<br /> however, the compound shall not be applied over any resulting freestanding water. Should the film of compound be
<br /> damaged from any cause before the expiration of 7 days after the concrete is placed in the case of structures and 72 hours in
<br /> the case of pavement,the damaged portion shall be repaired immediately with additional compound.
<br /> • At the time of use, compounds containing pigments shall be in a thoroughly mixed condition with the pigment
<br /> uniformly dispersed throughout the vehicle. A paddle shall be used to loosen all settled pigment from the bottom of the
<br /> container,and a power driven agitator shall be used to disperse the pigment uniformly throughout the vehicle.
<br /> • Agitation shall not introduce air or other foreign substance into the curing compound.
<br /> • The manufacturer shall include in the curing compound the necessary additives for control of sagging, pigment
<br /> settling, leveling, de-emulsification, or other requisite qualities of a satisfactory working material. Pigmented curing
<br /> compounds shall be manufactured so that the pigment does not settle badly, does not cake or thicken in the container, and
<br /> does not become granular or curdled. Settlement of pigment shall be a thoroughly wetted, soft, mushy mass permitting the
<br /> complete and easy vertical penetration of a paddle. Settled pigment shall be easily redispersed,with minimum resistance to
<br /> the sideways manual motion of the paddle across the bottom of the container,to form a smooth uniform product of the proper
<br /> consistency.
<br /> • Curing compounds shall remain sprayable at temperatures above 4°C and shall not be diluted or altered after
<br /> manufacture.
<br /> • The curing compound shall be packaged in clean 1040-L totes,210-L barrels,or 19-L pails shall be supplied from a
<br /> suitable storage tank located at the job site. The containers shall comply with "Title 49, Code of Federal Regulations,
<br /> Hazardous Materials Regulations." The 1040-L totes and the 210-L barrels shall have removable lids and airtight fasteners.
<br /> The 19-L pails shall be round and have standard full open head and bail. Lids with bungholes will not be permitted. Settling
<br /> or separation of solids in containers, except tanks, must be completely redispersed with low speed mixing prior to use, in
<br /> conformance with these specifications and the manufacturer's recommendations. Mixing shall be accomplished either
<br /> manually by use of a paddle or by use of a mixing blade driven by a drill motor, at low speed. Mixing blades shall be the
<br /> Contract No. 10-OM7104
<br /> 85
<br />
|