About This Course

Rigid inclusions are used for ground improvement works and they are often designed as unreinforced concrete columns. The installation methods of rigid inclusions mainly involve full-displacement drilling methods or non-displacement techniques which both utilize pumped and pressurized in-situ concrete. Ground improvement with rigid inclusions often requires the use of low to medium strength concrete to achieve the project specific design criteria.

Concrete mix designs need to allow for sufficient workability and stability of the fresh concrete to be able to withstand external pressures from pumping and placement. In addition, the workability life and the early strength development also need to be considered to allow for high quality rigid inclusions as well as smooth and efficient column installation on site.

The presentation discusses the importance of adequate workability of the fresh concrete and the impacts of unsuitable concrete mix designs on the quality of the rigid inclusions as well as on potential disruptions in the construction process when the fresh concrete performance is inadequate. Fresh concrete properties like slump, spread, workability, stability, slump/ spread retention will be discussed and some common testing methods to assess the quality of fresh concrete for rigid inclusions are introduced. In addition, the presenter highlights some selected construction related aspects which may impact the quality of the rigid inclusions as a result of insufficient concrete placement and quality on site.