This study explores the possibility of using PCS in the surface layer of asphalt pavements. It looks into engineering aspects like stability, flow, air void content, unit weight, and VMA percentage of asphalt specimens containing petroleum contaminated soils (PCS). The variation in the engineering properties of the asphalt concrete was studied with incorporating different percentages of PCS into it and also with a variety of asphalt contents.
Change in the quantity of PCS in the asphalt specimen's results in a significant change in properties of asphalt concrete. This thesis looks into the change in properties of asphalt concrete with the addition of different percentages of PCS. A high content of PCS is expected to result in low stability of the mix. One way to meet the test specifications for mix having high PCS is by adding admixtures. Addition of different admixtures like limestone dust and fly ash results in improved engineering properties. This study also looks into the possibility of adding materials like fly ash to the same mix thereby enhancing the engineering properties of the mixes and at the same time getting rid of materials like fly ash.
A set of laboratory tests were needed to establish the change in the properties of the asphalt mix with change in PCS and admixture contents. The Marshall test method (ASTM D-1559-82) is used to determine the stability, flow, and air voids of the mixes. This method was used to study the variation in properties of the mixes with the addition of contaminated soils and admixtures.
From the test results, it can be concluded that PCS can be incorporated to hot mix asphalt because the asphalt mixes satisfy ODOT specifications for stability and flow even after adding 15% of PCS.
Mixes with more than 7.5% of PCS do not satisfy the ODOT requirements for air voids and VMA for high traffic surface course. This study clearly indicates that more than 7.5% of PCS cannot be added to the mix as it results in very low air voids. It is also found that with the addition of PCS the amount of asphalt cement required in the mix is reduced. This can result in very high savings. It is also seen that 2% of fly ash can be added to the mix, satisfying the ODOT specifications. This will result in effective disposal of fly ash, which is detrimental to environment.