To ensure the proper use of ductile iron manhole covers, attention must be paid to installation quality, ensuring accurate dimensions, secure installation, easy opening, and a clean and aesthetically pleasing appearance. When constructing the brickwork for ductile iron manhole covers, the inner diameter of the manhole opening should match the inner diameter of the manhole cover and grate. The installed manhole cover should be flush with the road surface. After pouring and laying concrete or asphalt for the manhole base, the cover should be opened and cleaned promptly to prevent mortar or asphalt from fusing the manhole cover and base together, which could affect future opening.
When installing manhole bases on cement roads, cast a 20cm thick C25 concrete ring beam on the brickwork at the manhole opening and smooth it. Ensure the manhole base is firmly secured on all four sides, level, and not loose. Cast a 40cm wide concrete protective ring around the manhole cover (or a 20cm wide concrete protective ring for cement roads, reinforced with steel bars). Allow at least 10 days for curing.
When constructing asphalt pavements, thin sheet metal should be used to cover manhole covers, or waste engine oil should be brushed onto the surface to prevent asphalt from spraying onto the manhole covers. When installing ductile iron manhole covers on asphalt pavements, care must be taken to avoid construction machinery directly running over the manhole base. When the pavement is cast as a whole, holes slightly larger than the manhole base should be reserved in the pavement for installation after the asphalt is laid.
