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.

1.1 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.

1.2 Part I, Sections 1-11, of this specification presents general requirements and requirements which are common to each precast concrete product covered by this specification.

1.3 Part II of this specification presents specific requirements for each manhole product in the following sections:

Note 1—Future products will be included in Part II in a future revision of this specification.

1.4 This is the metric (SI) companion to Specification C 478.

Note 2—This specification is a manufacturing and purchase specification only, and does not include requirements for backfill, or the relationship between field load conditions and the strength requirements of the manhole products and appurtenances. Experience has shown, however, that the successful performance of this product depends upon the proper selection of the product strength, type of foundation and backfill, and care in the field installation of the manhole products and connecting pipes. The owner of the project for which these products are specified herein is cautioned to require inspection at the construction site.