The purpose of this research was to investigate the efficacy of enzyme stabilization on unpaved, low-volume roads through formal field experimentation with a control section. An experimental site was divided into six lanes for treatment with water only, portland cement, a combination of portland cement and Enzyme A, Enzyme A only, Enzyme B only, and a generic liquid soap. Testing was performed after 30, 60, and 270 days from the date of construction by using a dynamic cone penetrometer, portable falling-weight deflectometer, Clegg impact soil tester, and nuclear density gauge. The results were evaluated by using analysis of variance and pseudo-Bonferroni procedures. The analyses showed that treatment with cement or a combination of cement and Enzyme A yielded higher California bearing ratio, modulus, and Clegg impact values than the other treatments. This outcome occurred despite the fact that treatment with Enzyme A in particular yielded a statistically significant increase in dry density compared with the other treatments. With respect to curing time, the effects of freezing and thawing caused various degrees of deterioration in the material properties, as expected. Given the results of this study, the researchers recommend caution in applications of enzymes for soil stabilization; appropriate laboratory testing, field testing, or both are recommended before wide-scale stabilization that uses enzymes is attempted on any site.
