Effect of loading frequency on dynamic modulus of rubber latex-modified asphalt concrete

One of the key material properties in Mechanistic design of flexible pavement design is the dynamic modulus of asphalt concrete. In order to improve the performance of asphalt pavement, various techniques of modifications of the physical properties of bitumen have evolved over the years using different materials like natural rubber (rubber latex). Research has also proved that dynamic modulus of asphalt concrete is influenced by loading frequency. It is on this basis that the present study was indented to investigate the effect of loading frequency on the dynamic modulus of rubber latex-modified asphalt concrete. The result of the study showed that the dynamic modulus of the modified asphalt concrete at 0.5%, 1%, 1.5%, 2%, 2.5% and 3% rubber latex increased from 73,188.27 to 198,703.64 PSI, 70,879.34 to 192,442.87 PSI, 69,197.70 to 187,877.09 PSI, 65953.17 to 179,067.94 PSI, 64,388.41 to 174,819.48 PSI and 64,388.41 to 160,086.18 PSI at loading frequencies of 0.1HZ, 1HZ, 5Hz, 10Hz and 25Hz respectively. This behaviour is comparable with that of unmodified asphalt concrete indicating that rubber latex-modified asphalt concrete is adequate for design and construction of asphalt pavement. The result however, showed an optimum dynamic modulus at 0.5% rubber latex at all loading frequencies investigated.