Effects of Filler Properties on Fatigue Performance and Bond Strength of Asphalt Mastics

Mineral fillers are a vital part of asphalt mastic and mixtures that are known to have a major role in the mixtures' performance. A better understanding of the effects of the filler properties on asphalt mastic is important to control the distresses of the asphalt mixtures. This study evaluates the effects of physical and chemical properties of filler on fatigue and bond strength of asphalt mastic. Twelve asphalt mastics are prepared in the laboratory using three types of asphalt and four types of fillers. A filler to binder ratio of 1 (by mass) is used for all mastic sample preparation in the laboratory. Rigden voids (RV), fineness modulus (FM), calcium oxide (CaO), and methylene blue value (MBV) are used as properties of the filler for characterizing the fillers. The fatigue cracking behavior of asphalt mastic is evaluated using linear amplitude sweep (LAS) test, and asphalt bond strength (ABS) test is used to evaluate the interfacial bond strength between aggregate samples and mastics. The results from LAS test showed that the rolling thin-film oven (RTFO) aged mastic with a high percentage of FM containing filler has a better fatigue life than RV, CaO, and MBV containing filler. For pressure aging vessel (PAV)-aged mastic, the overall test result indicated that the fatigue cracking resistance of mastic is dependent on the interaction between base asphalt binder and filler type. The failure criteria of the LAS test method is an important parameter to characterize the mastic properties. The LAS and ABS test methods reveal that mastics prepared with high MBV and low CaO containing filler have better bond strength and worst fatigue performance. The bond strength performance of the mastic prepared with high FM filler is worse than base asphalt. FM, MBV, and CaO are major filler properties that could influence the asphalt mastic's fatigue and bond strength performance.

Automated summary

Mineral fillers play a crucial role in the performance of asphalt mastic and mixtures. This study evaluates the effects of filler properties on the fatigue and bond strength of asphalt mastic. Various tests are conducted to assess the cracking behavior and interfacial bond strength of asphalt mastics containing different types of fillers. The results indicate that the properties of filler, such as fineness modulus, calcium oxide, and methylene blue value, significantly impact the fatigue and bond strength performance of the asphalt mastic.