Using Food Industry Byproduct to Stabilize an Expansive Clay

The process of purifying agricultural products, at various food processing plants, generates waste materials that consist of precipitated calcium carbonate, organic debris, and trace amounts of soil and agricultural contaminants. A specific food-processing waste, hereafter referred to as a food industry byproduct, FIBP, is typically stockpiled on land adjacent to the corresponding food processing facilities due to its large volume and chemical composition. The FIBP also contains commercially available unspent lime products, which makes its reuse viable in various applications. An example is construction applications where an organic content of up to 5% by weight is allowed, such as treating expansive clays. Traditionally, lime stabilization has been used for improving the properties of expansive clays, where ground improvement methods are necessary for a large area. However, the process of producing lime is resource- and energy-intensive as it includes crushing and heating limestone in kilns to extract lime. Therefore, one specific doubly sustainable application is the treatment of expansive clays using the FIBP instead of lime. The main application tested here is the treatment of expansive clayey soils underneath a stretch of State Highway 95 near Marsing, ID. Other potential applications are in road and embankment construction. To evaluate the potential of expansive clay stabilization utilizing the FIBP, a series of geotechnical and environmental laboratory testing were conducted to measure the engineering properties (e.g., swell potential, permeability, and strength properties) of expansive clay amended with FIBP. Preliminary testing on blends with an expansive clay suggests benefits such as decreased swelling potential, increased density, and leachate immobilization.