| dc.description.abstract | Soil classification is very important in engineering applications since it categorizes soil into
groups of similar characteristics. There are various classification systems that have been
developed, but the most commonly used in engineering soil are the AASHTO and USCS. These
classification schemes are based on the particle size, liquid limit and plasticity because these
index properties of soil are fairly stable. At the moment the laboratory methods for obtaining
these soil properties are costly and time consuming hence making the engineering classification
an involving process. This study developed rapid protocol for expediting engineering
classification of soil through the use of near-infrared (NIR) spectroscopy. NIR spectroscopy in
determining chemical, organic and physical composition of soil has been proven to be useful;
which is rapid, economical and reduces drudgery. This research focused on the application ofthe
NIR within the range of 350nm and 2500nm and was found with over 67% correlation with soil - properties used in engineering classificationif'h.¢ correlation encouraged the application of near ..•
infrared spectral reflectance in identifying engineering classes of soil. More than 70% overall
correct identification of AASHTO engineering classes of soil was registered. This predictive
accuracy demonstrated that near infrared spectral reflectance can be useful in classifying soil into
different engineering classes. Together with the time and cost gains that researchers have
recently shown on spectral reflectance over convectional soil testing, the results from this study
reflectance. Furthermore, the spectral reflectance was able to detect subtle differences between
neighbouring engineering classes which could have been the result of hard boundaries imposed
by the existing engineering classification schemes. Consequently, reconstruction of classes in
engineering classification was suggested by use of near infrared spectral reflectance. | en |
