504PCCP FINISHING AND CURING

504.01Description

All PCCP surfaces shall be finished a nd cured in accordance with the following.

MATERIALS

504.02Materials

The materials shall be in accordance with the following:

Curing Materials .......................................................... 912.01

CONSTRUCTION REQUIREMENTS

504.03Finishing

PCCP shall be finished with equipmen t in accordance with 508.04. The operations shall be controlled so that an excess of mortar and water is not worked to the top. Long-handled floats may be used to smooth and fill in open textured areas in the PCCP.

Hand methods of finishing may be used when finishing equipment breaks down or in tight working areas where field conditions limit the use of mechanical devices. Hand placed concrete shall be further finished by means of a longitudinal float or a transverse smoothing float in accordance with 508.08(a).

The edges of formed PCCP adjacent to HMA or compacted aggregate shall be tooled. A continuous radius with a uniform smooth dense mortar finish shall be produced.

The PCCP surface shall be textured with a double thickness burlap drag or a 30 minimum 4 ft wide turf drag.

The textured surface of PCCP shall be tined, unless otherwise specified. Tining 504.03

shall consist of transverse grooves that are between 3/32 and 1/8 in. in width, between 1/8 and 3/16 in. in depth, and be spaced as follows: 5/8 in., 1 in., 7/8 in., 5/8 in., 1 1/4 in., 3/4 in., 1 in., 1 in., 1 in., 1 in., 3/4 in., 7/8 in., 1 3/4 in., 7/8 in., 3/8 in., 1 in., 1 in., 1 1/4 in., 1 1/2 in., 7/8 in., 3/4 in., 7/8 in., 1 in., 7/8 in., 1 in. The grooving pattern shall be repeated across the pavement. The grooves shall be formed in the plastic concrete without tearing the surface and without bringing pieces of the coarse aggregate to the top of the surface. 40

Texturing and curing operations may be performed by a single machine subject to satisfactory performance.

Areas of PCCP which are not finished in accordance with these requirements shall be corrected by retexturing.

Retexturing shall consist of cutting longitudinal or transverse grooves in the PCCP surface by means of saw blades or other approved devices. The grooves shall be spaced 3/4 in. center to center and be 1/8 in. in width and depth. Alternative patterns may be 50 used, subject to approval. The PCCP surface, after cutting, shall not be polished.

504.04Curing

Curing materials shall be applied to exposed surfaces and sides of newly placed PCCP within 30 minutes after the finishing operations have been completed, or as soon as marring of the concrete does not occur. Paving operations shall be immediately suspended if sufficient curing materials are not available on site.

When forms are used, the edges of the pavement shall be cured immediately upon removal of the forms. The edges shall be covered with curing materials equal to the 60 material used on the surface or banked with soil 12 in. wide or greater.

When conditions arise which prevent immediate application of curing materials, the paving operation shall be suspended and the PCCP shall be kept wet with a fine spray of water. The fine spray of water shall continue until application of curing materials resumes.

When blended portland pozzolan cements, fly ash, or slag cement are used in the concrete mix, the average ambient temper ature must be above 50°F for the curing period. The average temperature shall be calculated based on hourly temperature 70 measurements taken at the jobsite or from published weather station data within 10 miles of the jobsite. If the temperature restrictions are not met during placement or during the required curing period, curing shall continue and the PCCP shall not be opened to traffic until the strength requirements are met.

If liquid membrane forming compounds are used as the curing method and open to traffic strength has been achieved, the ro ad may be opened to traffic and the 96 h stipulation stated below will not apply. Except when liquid membrane forming compounds are used, curing shall be continuous for 96 h unless a longer period is 504.04

ordered. Curing shall be in accordance with the following. 80

The curing compound shall be mixed thoroughly within 1 h before use. The application shall be a minimum spreading rate of 1 gal. of liquid coating for every 150 sq ft of concrete surface. Curing compoun d shall be applied to provide a uniform, solid, white opaque coverage on all surfaces, similar to a white sheet of paper.

All concrete cured by this method shall receive two applications of the curing compound. The first application shall be applied immediately after surface water has disappeared and surface texturing has been applied. If formwork has been used, both 90 applications of curing compound shall be applied immediately after the formwork is removed. The second application shall be applied after the first application has set.

The curing compound may be warmed in a water bath during cold weather at a temperature not exceeding 100°F. Thinning with solvents will not be allowed. Non- uniform film rates will result in the discontinuance of that application method.

A new coat of curing compound shall be applied to areas damaged by rain or other means during the curing period. The recoating shall be applied as soon as possible and at a rate equal to that specified for the original coat. 100

The PCCP shall be covered with wet burlap laid directly on the surface and kept wet with a fine spray of water. This initial burlap shall receive an additional covering of wet burlap no later than 9:00 a.m. the day following its placement. The two layers of burlap shall be kept wet for the required curing period.

The PCCP shall be kept wet with a fogged spray of water, or be covered with wet burlap laid directly on the surface and kept wet with a fine spray of water. The PCCP 110 shall receive a cover no later than 9:00 a. m. the day following its placement. If white burlap polyethylene sheets are used, the burlap side shall be wet or the surface of the concrete thoroughly wetted just prior to the blanket being placed.

The covers shall be weighted down on each edge and shall be as wide as the full width of the pavement being cured. Adjoining covers shall overlap 12 in. or more and the laps held securely in place.

Covers may be reused provided they are airtight. All torn covers shall be repaired with patches. All units not in accordance with these requirements shall not be used. 120

The covers shall remain in place for the required curing period.

504.05Method of Measurement

Finishing and curing operations will not be measured for payment. 504.05

504.06Basis of Payment

The cost of finishing the PCCP surface furnishing and placing curing materials shall be included in the cost of the PCCP.