Pouring Concrete Manholes With Volumetric Mixers
- Two or more sewer/stormwater lines intersect;
- The size of the sewer/stormwater lines change;
- The sewer/stormwater line alignment changes; and/or
- The sewer/stormwater line grade changes.
The diameter of the system can also dictate placement.
When Are Concrete Manholes Installed?
Construction and/or installation takes place toward the end of the sewer project itself. Yet, since a manhole cover itself ranges in size from 22 inches to 60 inches and weighs, on average, between 250 pounds and 300 pounds, adequate design and poured concrete is a must.
The cover, such as a concrete sewer cover, rests on the inner lip at the top, accessible for sewer and/or utility workers at all times.
2 Types Of Concrete Manholes
While most project plans call for precast manholes, some specify using a cast-in-place — or monolithic — method. In this situation, the area is prepared and excavated before form placement and concrete pouring. This method eliminates joints, reducing the risk of sections shifting with soil movement.
Designed to meet the specific needs of various projects, precast manholes range in size from 48 inches to 144 inches. Once lowered into place, the surrounding area can be backfilled and remaining work for the project completed.
What’s The Difference Between A Manhole Cover And An Access Cover?
Manhole covers are essentially lids, with the sole purpose of preventing anyone and/or anything from entering the underground area, such as drains. Because of their designed heft, special tools are usually needed to remove them for access. Cast iron and galvanized steel are the two most common metals used in making manhole covers. But, some covers use a concrete and metal blend.
Access covers focus more on aesthetics but also subtlety. They’re more common in roadway and paving projects, along with on driveways and sidewalks. This is because manholes are rarely placed in traffic lanes unless necessary due to accessibility and safety concerns.
Why Volumetric Mixers Are Perfect For Concrete Manholes
Volumetric mixers specialize in on-demand exactness in terms of producing the same mix design time and time again with no deviation. This gels perfectly with precast production which relies on repetition to create high-quality products their customers count on. But, cast-in-place jobs receive numerous benefits from using a volumetric mixer, such as reduced employee downtime and accurate aggregate measurements.
For manhole covers, these jobs are generally small, sometimes needing amounts down to the quarter yard. Volumetric mixers allow you to produce this small amount, time and time again.
Interested in learning how our line of volumetric concrete mixers can help you more efficiently complete water and sewer projects? Contact us today!