The Job
This MSE wall backfill project is located on Interstate 95 north of Baltimore, Maryland. The Express Toll Lanes will add extra capacity up the center of the existing roadway. This project is adjacent to a previous CJGeo project, where we placed 2,000 CY of CJFill-Ultra Lightweight cellular concrete as part of the Clayton Road Overpass reconstruction.
The Challenge
A 96″ diameter PCCP raw water supply line runs parallel to Interstate 95 along most of the project length. Originally, there was quite a bit of room between the roadway and the water line. However, as lanes are added, it’s gotten closer and closer to the PCCP water line. As part of this project, there are extensive ramp and embankment sections. They are immediately adjacent to the waterline, which is not in a condition to see any increase in loading.
To address this, designers specified lightweight material for the MSE wall backfill material.
The CJFill MSE Wall Backfill Solution
Originally designed for backfilling with Lightweight Expanded Shale Aggregate (LESA). CJGeo worked with the contractor to develop a hybrid MSE wall backfill material of 30lb/cuft cellular concrete and traditional weight 57 stone.
The relative depths of the two materials was selected so that the average density of the mass was equal to that of an entirely LESA backfill. This resulted in only needing roughly 2/3 the volume of lightweight backfill material.
Lightweight backfill is rarely less expensive as soil or traditional aggregates. However, by leveraging the very low unit weight of cellular concrete, a blended solution was possible that saved significant amounts of money.
CJGeo generated as much 500CY per day of CJFill-Ultra Lightweight to backfill the wall. The 30lb/cuft wet cast density provides adequate pull out resistance, and 140psi of unconfined compressive strength at 28 days.
Speak With An Expert
Facing a similar MSE wall backfill challenge? Give us a shout or shoot us a text. Click the state marker for the location of your project for contact info for the appropriate rep.
