Influence of Diatomite and Mineral Powder on Thermal Oxidative Ageing Properties of Asphalt

Abstract

Ageing of asphalt affects the performances of asphalt pavement significantly. Therefore, effects of diatomite and mineral powder on ageing properties of asphalt were investigated systematically in order to improve the antiageing property of mixture. Thin film oven test (TFOT) was used to conduct the short term ageing in laboratory. Softening points, penetrations, force ductility, low temperature creep properties, and viscosities of asphalt mastics were tested before and after TFOT, respectively. Results indicated that percent retained penetration (PRP) increased with the increasing of fillers. Increment of softening point (ΔT), ductility retention rate (DRR), deformation energy ageing index (JAI), and viscosity ageing index (VAI) of asphalt mastics nonlinearly decreased with the increasing of fillers. Ageing of asphalt was reduced by diatomite and mineral powder. And the antiageing effect of diatomite was better than that of mineral powder as a result of its porous structure. It is suggested that the mineral powder could be reasonably replaced by diatomite in order to reduce thermal oxidative ageing of asphalt mixture. The optimal content of diatomite 12.8% is also suggested for engineering.

Laboratory Study on Properties of Diatomite and Basalt Fiber Compound Modified Asphalt Mastic

“…This is an important means to prolong the service life of asphalt pavement. At present, the common asphalt modifier can be divided into the polymer-modified material and the inorganic modified material [6][7][8][9][10][11][12][13][14]. By the inorganic modified material utilization such as diatomite and basalt fiber as the modifier, not only the asphalt performance could be enhanced, but also the polymer modifier pollution to the environment could be avoided.…”

Short-Term Aging Effect on Properties of Sustainable Pavement Asphalts Modified by Waste Rubber and Diatomite

“…Softening point is a widely used parameter to evaluate high temperature susceptibility of asphalt. It is the temperature at which a phase change occurs [20]. The Ring and Ball Softening Point test (TR&B) (SYD-2806, Beijing Zhonghangkegong Instrument Co., Ltd., Beijing, China) was used to measure the temperature at which the asphalt could not support the steel ball with the weight 3.5 g at the heating rate 5 • C/min according to ASTM D36.…”

“…Wet process was widely adopted to prepare the modified asphalt binders [11,[25][26][27], which can make crumb rubber, diatomite, and asphalt react for a period and take advantage of the benefits of all base ingredients [4]. A high speed shear homogenizer [20] was employed to stir the modified asphalt (shown in Figure 1), the oil bath as a heating device can control the temperature of the modified asphalt when stirring. The preparation process mainly included three steps: heating of raw materials; shearing and mixing of ingredients; and storing of modified asphalt binder.…”

“…The results shown in Figure 8 reveal that creep stiffness (S) of asphalt binders linearly increases while the m-value linearly decreases with increasing time. This is because the light component in asphalt transforms into a heavy component, which make the asphalt become harder [20,21]. Thus On the contrary, the elastic recovery property is distinct for the crumb rubber modifying process because of the swelling reaction and degradation action.…”

“…The results shown in Figure 8 reveal that creep stiffness (S) of asphalt binders linearly increases while the m-value linearly decreases with increasing time. This is because the light component in asphalt transforms into a heavy component, which make the asphalt become harder [20,21] The results shown in Figure 8 reveal that creep stiffness (S) of asphalt binders linearly increases while the m-value linearly decreases with increasing time. This is because the light component in asphalt transforms into a heavy component, which make the asphalt become harder [20,21].…”