College of Engineering
Materials Engineering Department
BS in Materials Engineering
Non-toxic food thickeners were investigated as a solution for thickening mud to mitigate the effects of mudslides. All soil was obtained from a site on the California Polytechnic State University campus where a mudslide occurred in 2017. Guar gum was mixed into the soil at 1 wt% and 10 wt% of the moisture content in the soil. Whey protein was mixed into the soil at 2 wt% and 19 wt% of the moisture content in the soil. The soils’ liquid limit was found using the Casagrande cup testing method. Liquid limit testing indicated that thickeners raised the liquid limit, most significantly the higher concentration of guar gum. The viscosities of the treated and untreated soils were found using a viscometer. Viscosity measurements indicated that 10 wt% guar gum had the greatest immediate thickening effect, while after 72 hours, 19 wt% whey had the highest viscosity. Soil and thickener interactions were examined using scanning electron microscopy (SEM). Tests for soil toxicity were conducted by seeding annual ryegrass in the soils, and comparing the biomass of the ryegrass grown in each soil treatment, as well as measuring the Degrees Brix of the grasses. The soil toxicity showed that all treatments were non-toxic to ryegrass, with a low concentration of whey protein having an unintended fertilizing effect.
Available for download on Saturday, June 13, 2020