Stabilisation of base course materials with nanoemulsions.

Abstract

The province of KwaZulu-Natal, like many geographical locations in South Africa and around the globe, lacks quality materials suitable for pavement construction. Pavement engineers are aware of the dangers of utilising substandard materials in building roadways due to their susceptibility to several forms of distress. Aside from the unrestrained emission of carbon compounds to the atmosphere and the high cost associated with hauling standard materials to the construction site, the continuous depletion of these natural materials results in distortion of the environment. Several techniques are employed to enhance substandard construction materials using traditional and non-traditional stabilisers; however, many researchers have proven the latter's effectiveness at improving marginal paving materials over the former. The use of nanotechnological products, including nano polymers and nano-modified emulsions on South African pavements, is still at the experimental stage; however, numerous research studies using this technology are promising and could lead to the ultimate transformation of pavement structures that will satisfy the current environmental demands. Nanoemulsions can be formed using emulsifying agents to break down larger droplets of one liquid into smaller, more uniformly dispersed droplets throughout another liquid. This study aims to improve the performance of a substandard base course material with nanoemulsions. The study also seeks to provide a long-lasting wearing course for unsurfaced roads in South Africa and across the globe. In this current study, two stabilisers designated as nano A and B were obtained from two manufacturers in South Africa. The stabilisers were mixed by mass at 0,7% - 1,5% with the soil sample, and the results indicate an optimum content at 1% and 1,2% for nano A and B, respectively. The impact of the stabilisers on the material was evaluated through California bearing ratio, unconfined compressive strength, and indirect tensile strength tests. Analysis of the experimental results reveals that nano A and B significantly improved the bearing strength of the material by as much as 53% and 92%. Significant improvements were also noted in the results of unconfined compressive strength and indirect tensile strength. Evaluation of the effect of rapid and 28-day curing conditions on the specimens yields similar results. Nano B also showed great potential by creating a hydrophobic effect in the soil matrix. These enhancements would prevent moisture damage in the stabilised layer and ensure the construction of quality roads.