830CONCRETE CURING MATERIALS

696

CONCRETE CURING MATERIALS

830.01Burlap Cloth and Waterproof Covering Material

Burlap cloth and waterproof covering material shall be of sufficient length and width to extend beyond the edge of the concrete a distance of at least twice the thickness of the slab. Sections of covering material shall be lapped at least 18 inches {450 mm}. The surface and both sides of a concrete slab shall be completely covered. The covering shall be so placed and secured as to cause it to remain in total contact with the exposed surface. Burlap cloth shall be saturated with water before being placed and shall be kept wet while in position. The covering shall remain in position for six days after the concrete has been placed unless otherwise specified or directed.

171 modified to omit the elongation requirements when the sheeting is internally reinforced with a cord net having a cord spacing of 1/4 to 1/2 of an inch {6 to 13 mm}. (Net may be nylon or other approved material.)

830.02Impervious Membrane

Impervious membrane compounds shall meet the requirements of ASTM C 309, Class A. Type 2 white pigmented shall be used on concrete pavement. Other types may be used on other concrete. Membrane liquid shall be applied under pressure with spray nozzles in such a manner as to cover the area being treated with a uniform film. For concrete pavement the rate of application shall be 1 gallon {4 L} to not more than 135 square feet {13 m²}, applied in two applications. For sidewalks the rate of application shall be 1 gallon {4 L} to not more than 200 square feet {19 m²}.

830.03Wetted Earth Or Sand

When this type of curing is used, the pavement shall be cured initially with burlap cloth, polyethylene sheets, or waterproof paper, as specified in Article 830.01, until after final set of the concrete or, in any case, for 12 hours after placing the concrete. As soon as the covering material is removed, the surfaces and sides of the pavement shall be covered with a blanket of earth or sand not less than 2 inches {50 mm} thick. If the earth or sand covering becomes displaced during the curing period, it shall be replaced to the original depth and saturated with water for three days and thoroughly wetted down during the morning of the fourth day; the cover shall remain in place until the concrete has attained the required strength. When permission is given to open the pavement to traffic, the covering material shall be removed and the pavement cleaned and swept. Earth or sand used in this method of curing shall be free of sticks, stones, or other matter which might injure the surface of the concrete. The material shall contain no ingredients which would be detrimental to the concrete or discolor the surface finish.

830.04Straw

Straw used as a supplement to the curing materials noted in Article 830.01 and 830.02 for cold weather protection shall be suitable for the purpose intended and approved each time it is used. PRECAST CONCRETE PRODUCTS

831.01Description

All precast concrete products, except precast non-prestressed concrete bridge members, shall be furnished from an approved producer that is participating in, and meeting the requirements given in ALDOT-364. ALDOT 364 is the "Procedure for Inspection of Concrete Pipe, Precast Manholes, Precast Box Culverts, and Miscellaneous Precast Concrete Products". CONCRETE JOINT FILLERS, JOINT AND CRACKSEALANTS, AND WATERSTOP MATERIALS 697

Producers of precast concrete products shall be shown in List I-8, PRODUCERS OF PRE-CAST CONCRETE PRODUCTS, of the Department's "Materials, Sources, and Devices with Special Acceptance Requirements" Manual. Information concerning this list is given in Subarticle 106.01(f) and ALDOT-355. Precast products will be evaluated at delivery according to the criteria in AASHTO R 73. CONCRETE JOINT FILLERS, JOINT AND CRACKSEALANTS, AND WATERSTOP MATERIALS

832.01Preformed Joint Filler

Preformed joint filler units shall be furnished in one piece of the length, thickness, and depth shown on the plans for a complete joint, unless otherwise authorized by the Engineer. When the use of more than one piece is authorized, the abutting ends shall be fastened securely and held accurately in place to correct shape by stapling or other satisfactory means. When a preformed filler is used with dowels or other protruding items which must pass through the filler, clean-cut holes, accurately spaced and not more than 1/8 of an inch {3 mm} larger than the protruding item shall be provided. Damaged filler units shall be rejected. Joint fillers used in conjunction with expansion joints will require the use of a joint sealer in order to provide a functional joint. Sealants shall be one of the appropriate types specified in Article 832.02 or Subarticle 832.03(a), unless a specific type is specified by the plans.

Preformed bituminous joint filler for general use in bridge, culvert, and drainage structure work shall meet the requirements for one of the following "Types" unless a specific "Type" is required by the detailed plans:  Type 1 - AASHTO M 33  Type 2 - AASHTO M 213, modified to allow a maximum of 25% water absorption.

Expansion joint filler for concrete pavement, curb, gutter, combination curb and gutter, flumes, slope paving, and other miscellaneous concrete structures shall meet the requirements as given for one of the following materials:

832.02Joint and Crack Sealants

Joint and crack sealants may be used for sealing both expansion joints and construction joints in concrete units other than bridges within the following limitations: Vertical joints in concrete units such as curbs, etc. will require the use of a non-sag compound. Construction joints 1/4 of an inch {6 mm} or less in width will not require sealing unless specified by plan details. The shape factor of joint sealant is most important. The joint configuration shown by the plan details may require the use of a backer rod or strip to ensure proper shape. When a backer rod or strip is necessary, it shall be compatible with the sealant and shall have no bond or reaction between the sealant and the backer rod or strip. A bond breaking tape may be used to ensure no bond occurs between the two materials. Requirements for joint and crack sealants are noted in the following Subarticles; however, the Contractor may substitute an approved preformed elastomeric seal meeting the requirements of Subarticle 832.03(a) in lieu of a sealer provided such is furnished at no additional cost to the Department. A certified test report showing actual test results shall be furnished with each lot of joint sealer furnished to each project. Each lot of sealant shall be delivered in containers plainly marked with