A contractor on a Rideau Street mid-rise was losing sleep over foundation backfill last winter. The soil was a mix of silty sand and chunks of limestone till, and the inspector flagged inconsistent density readings from the field crew. We ran a series of modified Proctor tests on samples taken from the lift, cross-referenced them with field density data from a sand cone density test, and identified the optimum moisture content that the crew had been missing by almost three percent. That adjustment saved them from re-compacting two floors' worth of backfill before the first big freeze. In Ottawa, where native soils range from sensitive Leda clay in the east to dense glacial till in the west, the Proctor test is not just a box to check—it is the reference curve that every compaction spec hangs on.
Compaction without a Proctor curve is just guesswork—and guesswork in Ottawa's silty till costs re-compaction by the metre.
