ASTM C858-19 pdf download.Standard Specification for Underground Precast Concrete Utility Structures.
5.2 Aggregates—Aggregate shall conform to Specification C33 and light-weight aggregate shall conform to Specification C330, except that the requirements for grading shall not apply. 5.3 Admixtures—Admixtures may be used provided such admixtures are not injurious to other products used in the concrete.
5.3.1 Chemical Admixtures—Chemical admixtures shall conform to Specification C494/C494M.
5.3.2 Fly Ash and Pozzolanic Admixture—Fly ash or other pozzolanic admixtures shall conform to Specification C618. 5.3.3 Air-Entraining Admixtures—Air-entraining admix- tures shall conform to Specification C260. 5.4 Water—Water used for curing, washing aggregate, or mixing concrete shall be clean and free ofinjurious amounts of oil, acids, alkalis, salts, organic materials, or other substances that may be incompatible with concrete or steel.
5.5 Steel Reinforcement:
5.5.1 Wire Reinforcement—Wire reinforcement shall con- form to Specifications A82/A82M or A496/A496M.
5.5.2 Wire Fabric Reinforcement—Wire fabric reinforce- ment shall conform to Specifications A185/A185M or A497/ A497M. 5.5.3 Bar Reinforcement—Bar reinforcement shall conform to Specifications A184/A184M, A615/A615M, A706/A706M, or A996/A996M. 6. Manufacture
6.1 Forms—Forms shall be accurately constructed and strong enough to maintain the structure’s dimensions within the tolerances given in Section 8. Forms should be constructed in such a manner as to minimize the seepage of water. All casting surfaces shall be smooth nonporous material.
6.1.1 Cleaning and Oiling—Forms shall be cleaned before each use. New forms shall be free of paint or other protective coatings that might cling to the surface of the structure. Releasing agents applied to the form to aid in breaking the bond between the form and the concrete shall not be injurious to the concrete.
6.2 Reinforcement—Steel reinforcement shall conform to the requirements of this specification and shall be securely positioned in the form to maintain design concrete cover given in Section 7 during concrete placement. All chairs, bolsters, braces, and spacers in contact with form and reinforcing rod shall be of material that will not deteriorate.

6.3 Mixture—The aggregates shall be sized, graded, propor- tioned, and thoroughly mixed in a batch mixer with proportions of cement and water as will produce a homogeneous concrete having the required specified compressive strength. If Ready- Mix concrete is used, it shall be in accordance with Specifica- tion C94/C94M.
6.3.1 Water-Cementitious Material Ratio—Concrete that will be exposed to freezing and thawing shall have a water- cementitious ratio of 0.45 or less.
6.3.2 Air Entrainment—When there is a risk that the con- crete may be exposed to a freeze-thaw cycle, the concrete mixture shall contain 5.5 6 1.5 % air by volume as determined by Specification C231.
6.4 Concrete Placement—Concrete shall be deposited as nearly as practicable in its final position. Concrete shall be placed in the form at a rate such that the concrete is plastic at all times and flows readily into all parts ofthe form and around all reinforcement steel and embedded fixtures without segre- gation of materials. Concrete that has partially hardened or has been contaminated by foreign material shall not be deposited in the form.
6.5 Curing—Structures shall be cured by an accepted in- dustry method that will develop the required 28-day compres- sive strength without affecting the long-term durability of the concrete.ASTM C858 pdf download.