Effect of Clay Soil from Mbiama on the Mechanical and Moisture Damage Properties of Asphaltic Concrete

Abstract

Many studies have shown the damaging effect of moisture on conventional asphalt concrete when submerged in water for a time period under the application of traffic load. This study is aimed at determining the effect of partially replacing the mineral filler portion of the total mix with 2-14% clay, sourced from Mbiama on asphaltic concrete. The Marshall Stability Design Method was used to determine the optimum bitumen content of 5% and to evaluate asphalt concrete properties after soaking durations of 2, 4, and 7 days. The clay used for the study underwent Atterberg Limit Test for classification. The results show that the clay adhered to OL and A-3 in both the USC and AASTHO soil classification systems. The Marshall Stability value for the control sample increased from 8.4 kN to 16.54 kN at 4% clay addition, given a 49% increase in stability over the control sample. Soaked clay modified asphalt concrete samples maintained a significant retained stability across all soaking duration with superior moisture resistance capabilities.