Laboratory evaluation of thermal cracking in bitumen and asphalt mixture modified with nano-silica

Bitumen modification using additives is one of the ways to improve the performance characteristics of bitumen and asphalt mixture. Nanomaterials are one of the newest technologies, which is rapidly advancing in various sciences. The many advantages of this technology have led researchers in the field of pavement to use it to improve the properties of asphalt mixtures. Heat cracking is one of the most common road failures. Considering the relationship between fatigue failure and grooving in bitumen and asphalt mix at medium and high temperatures and the lack of studies on thermal cracking at low temperatures, it is important to evaluate the relationship between thermal cracking parameters in bitumen and asphalt mix. For this purpose, flexural beam rheometer (BBR) test for bitumen and SCB flexural semicircle test for asphalt were used. The purpose of this study is to investigate the behavior of bitumen and asphalt mixture modified with nano-silica. The results showed that the strength of the asphalt mixture modified with silica nanoxide was cracked and the modulus of resistance was about 1.6 and 1.4 times. The index related to moisture sensitivity of asphalt mixtures also increased by about 7% compared to the control sample. However, bitumen test results indicate a decrease in the performance of nanosilica-modified bitumens at low temperatures. The toughness results in SCB test for asphalt mix are consistent with BBR test results in bitumen. Tensile bonds of FTIR test and increased stiffness in asphalt mixture are effective factors in improving the behavior of nanosilica modified bitumen compared to the control sample.