In some instances during a sewer project, an existing catch basin or manhole's existence is no longer needed. In such situations, such a structure may be in a location where its complete removal may not be necessary. In these cases, the project engineer may require that the structure be 'abandoned' . 

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The term 'abandoned' in such a case, most commonly means filled with grout, low strength mortar, or concrete (depending on the specification), and eventually covered with the final surface material, be it roadway or greenspace. The project engineer may require that the casting frame and cover be removed as part of the abandonement. Low strength mortar is very commonly used as the backfill material though some engineers may allow aggregate to be used as backfill.