Earthen fills obtained either from excavation on site or imported from offsite borrow pits feature on most civil engineering and building projects. Dams, levees and highway and rail embankments consume large quantities of earthen fills - often using cohesive materials.
Laboratory compaction tests (Standard and Modified Proctor Tests) were developed in the 1930s and 1950s to model the performance of contemporary sheepsfoot rollers towed by tractors in use at the time. These tests generate a laboratory ‘compaction curve’ that relates dry density achieved during the test to the moisture content of the soil at the time of compaction.
Unfortunately, these tests are outdated and are a poor model for production compactors commonly used today.
Since these tests, and similar tests in use in other jurisdictions, do not model well modern compactors, specifications based on these tests often lead to basic engineering objectives not being met, allowing for issues to develop during the lifetime of the compacted fills, particularly with respect to volume change on wetting.
Earthen Construction with cohesive fills is the one part of geotechnical, and indeed civil, engineering where project specifications consistently do not ensure engineering and performance objectives will be achieved and QC test results confirm this to be the case.
An improved understanding of the compaction process in terms of the performance of modern compactors in terms of their actual compaction curve (dry density-moisture content relationship) leads to distinct benefits:
Better performing compacted fills
A wider range of acceptable cohesive fill materials
A wider range for fill placement moisture contents
Wottesbrooke Earthwork Solutions offers specialist consulting services, giving you a full understanding of your earthworks needs and ensuring that engineering objectives are truly achieved during construction, saving you time and money.