No-Fines Concrete Backfill
No-Fines Concrete
Use of No-Fines Concrete Backfill has increased our ability to install reinforced retaining walls in locations where typical construction would not be possible because of property line constraints or limited excavation options. When using the Allan Block products with No-Fines concrete, the permeable concrete actually attaches to the back of the block and extends the depth of the retaining wall mass. This allows for taller retaining walls with less excavation than conventional geogrid reinforced retaining walls.
Typical geogrid reinforced walls require an excavation depth of 60% or more of the wall height; while a no-fines backfill wall, with similar site conditions, requires only 30 to 40% of the wall height. The recommended minimum structure depth of the no-fines concrete backfill, measured from the face of the wall to the back of the mass, is 24 in (60 cm). Limiting the excavation depth will not only save time and money, but it might make the difference between getting the job or not.
There are additional advantages to using the no-fines solution. Contractors are able to build with better production rates and with less manpower. The use of no-fines concrete backfill also eliminates the need for compaction and compaction testing of the reinforced soil. It provides superior wall drainage since the entire mass is permeable; therefore eliminating the need for wall rock in the cores and behind the wall. This pervious concrete backfill will provide a “solid” solution that can reduce the overall settlement behind the wall.
For more information on No Fines Concrete - Check out Tech Sheet - Building with No Fines Concrete

No-Fines Concrete
Engineering Properties:
- No-fines concrete backfill can be used with any of the Allan Block Retaining Wall Collections.
- No-fines concrete backfill typically consists of cement, fly ash, water and coarse aggregate. The quantity of cementitious material is approximately 500 lb/yd3 (297 kg/m3) with a water/cement ratio of approximately 0.30 – 0.40.
- No-fines concrete backfill is designed using 3/8 to 3/4 in (9.5 mm to 19 mm) aggregate with an aggregate/cement ratio of 6:1.
- The density of this product will vary with the density of the aggregate used, but will typically range between 100 lb/ft3 – 135 lb/ft3 (1600 kg/m3 – 2160 kg/m3).
- No-fines concrete backfill exerts pressure on the soil and Allan Block wall similar to loosely poured aggregate until cured.
- When using no-fines concrete backfill, the backfill zone will also serve as the required drainage or wall rock zone within the cores and directly behind the wall.
See the No-Fines Concrete Estimating Chart for more information.

