This specification covers materials in sheet form used for covering the surfaces of hydraulic cement concrete to inhibit moisture loss during the curing period and, in the case of the white reflective type materials, to also reduce temperature rise in concrete exposed to radiation from the sun. The following types are included: curing paper which can be regular or white, polyethylene film which can be clear or white opaque, and white-burlap-polyethylene sheet. The sheet materials furnished shall be tough, strong, resilient, and capable of withstanding normal job use without puncturing or tearing. The daylight reflectance of the white side of white curing paper shall be at least 50% when measured. The daylight reflectance of white polyethylene film and the polyethylene side of white burlap-polyethylene sheet shall be at least 70% when measured. Curing paper shall consist of two sheets of kraft paper cemented together with a bituminous material in which are embedded cords or strands of fiber running in both directions. The paper shall be light in color, shall be free of visible defects, and shall have a uniform appearance. White paper shall have a white surface on at least one side. The tensile strength of the curing paper shall be determined. Polyethylene film shall consist of a single sheet manufactured from polyethylene resins. It shall be free of visible defects and shall have a uniform appearance. The clear type shall be essentially transparent. The opaque film shall contain white pigment. The impact resistance of this film shall be measured. White burlap-polyethylene sheet shall consist of burlap extrusion coated on one side with white opaque polyethylene. The polyethylene material shall be securely bonded to the burlap so that there will be no separation of the materials during handling and curing of the concrete.

1.1 This specification covers materials in sheet form used for covering the surfaces of hydraulic cement concrete to inhibit moisture loss during the curing period and, in the case of the white reflective type materials, to also reduce temperature rise in concrete exposed to radiation from the sun. The following types are included:

1.1.1 Curing Paper.

1.1.1.1. Regular.

1.1.1.2 White.

1.1.2 Polyethylene Film:

1.1.2.1 Clear.

1.1.2.2 White Opaque.

1.1.3 White-Burlap-Polyethylene Sheet

1.2 The values stated in SI units are to be regarded as the standard. Inch-pound units are provided in parentheses for information only.

This specification does not cover materials such as burlap, cotton mats, or rugs used with additional applications of water to maintain a water-saturated environment on such surfaces. Procedures employing these materials are discussed in ACI 308R. Sheet materials having additional characteristics such as insulating properties and the ability to carry additional water to the curing region are commercially available but are not currently addressed in this specification.

1.3 The text of this standard references notes and footnotes which provide explanatory material. These notes and footnotes shall not be considered as requirements of the standard.