WP1 – Knowledge generation: lab testing

Photo above: Triaxial testing at NGI's soil mechanics laboratory (Photo NGI)

Research tasks

• T1.1 Sampling of industry by‐products (i.e., bioash, steel slag, waste paper sludge ash and biochar) and soft clay, quick clay and peat from the Norwegian GeoTest Sites (NGTS, RCN grant No. 245650/F50)
• T1.2 Perform laboratory experiments including geophysical methods on soils stabilised with industry by-products and identify optimum quantities and mixtures
• T1.3 Design, build and perform tests on a novel column experiment (model testing) to unlock new information about execution parameters affecting the integrity of stabilised soil
• T1.4 Establish correlations between monitored parameters (e.g., execution parameters, S‐wave velocity and curing temperature) and engineering properties measured at laboratory scale

Theoretical approach and methodology

Experimental investigations of industry by‐products for stabilising Norwegian soils currently fall short of obtaining relations between non‐destructive process monitoring data and engineering properties. The novelty of this work package is to design and perform innovative laboratory experiments across different scales and to adopt non‐destructive process monitoring of stabilised soil.

The obtained results will be the theoretical backbone to upscale, industrialise and automate soil stabilisation. WP1 will first obtain soil samples from the established NGTS sites Onsøy and Tiller‐Flotten and industry by-products from the consortium partners. Then, a range of laboratory mixtures will be prepared for the different materials and soils and tested using S‐wave velocity measurements. Unconfined compression, oedometer and triaxial tests will then be carried out on these samples.

The obtained results in combination with previous proof of concept studies will provide a solid foundation to determine optimum binder quantities and mixtures, and to obtain correlations between S‐wave velocity, curing temperature and engineering properties.

In addition, WP1 will design a half‐meter‐scale column experiment to study the role of execution parameters such as, for example, the mixing type tool, the mixing energy, the binder flow rate and the extraction rate of the mixing tool on the uniformity of stabilised soil in a controlled manner. The column tests will be crucial to test DFOS for distributed temperature and strain sensing of stabilised soil.