This specification covers the manufacture and purchase requirements of products used for the assembly and construction of circular vertical precast reinforced concrete manholes and structures used in sewer and water works. Reinforced concrete shall consist of cementitious materials, mineral aggregates, and water, in which steel reinforcement has been embedded in such a manner so that the steel reinforcement and concrete act together. Aggregates shall conform to the specification , except that the requirements for gradation shall not apply. Minimum compressive strength of concrete manhole products covered must meet the requirement. The aggregates shall be sized, graded, proportioned, and mixed with such proportions of cementitious materials and water as will produce as homogeneous concrete mixture of such quality that the products will conform to the test and design requirements. Concrete products shall be subjected to either steam or water curing. Test methods such as compression and absorption testing shall be performed.