Abstract:To solve the nanoparticles (NPs) agglomeration phenomena of nanometer calcium carbonate (nano-CaCO3) modified asphalt binder, in this paper, solvent-free CaCO3 nanofluids (NFs) were prepared based on surface-functionalized CaCO3 NPs to study the effect on asphalt. Microscopic structures, compositions, and thermal stability were characterized by Fourier transform infrared spectrometer (FTIR), X-ray diffractometer (XRD), transmission electron microscope (TEM), and thermogravimetric analyzer (TGA), respectively. … Show more
“…It appears that a specific concentration of FSN satisfies any rutting requirements. This result is in agreement with findings from other researches on nano-reinforced binders 20 , 39 – 42 . Figure 3 Analysis of Dynamic Shear Rheometer tests—rutting resistance of binder samples before and after aging: ( a ) control sample, ( b ) 0.1 wt.-% fumed silica nanoparticles (FSN), ( c ) 0.2 wt.-% FSN, and ( d ) 0.3 wt.-% FSN.…”
Warm mix asphalt (WMA) is gaining increased attention in the asphalt paving industry as an eco-friendly and sustainable technology. WMA technologies are favorable in producing asphalt mixtures at temperatures 20–60 °C lower in comparison to conventional hot mix asphalt. This saves non-renewable fossil fuels, reduces energy consumption, and minimizes vapors and greenhouse gas emissions in the production, placement and conservation processes of asphalt mixtures. At the same time, this temperature reduction must not reduce the performance of asphalt pavements in-field. Low aging resistance, high moisture susceptibility, and low durability are generally seen as substantial drawbacks of WMA, which can lead to inferior pavement performance, and increased maintenance costs. This is partly due to the fact that low production temperature may increase the amount of water molecules trapped in the asphalt mixture. As a potential remedy, here we use fumed silica nanoparticles (FSN) have shown excellent potential in enhancing moisture and aging susceptibility of asphalt binders. In this study, asphalt binder modification by means of FSN was investigated, considering the effects of short-term and long-term aging on the rheological, thermal, and microstructural binder properties. This research paves the way for optimizing WMA by nanoparticles to present enhanced green asphalt technology.
“…It appears that a specific concentration of FSN satisfies any rutting requirements. This result is in agreement with findings from other researches on nano-reinforced binders 20 , 39 – 42 . Figure 3 Analysis of Dynamic Shear Rheometer tests—rutting resistance of binder samples before and after aging: ( a ) control sample, ( b ) 0.1 wt.-% fumed silica nanoparticles (FSN), ( c ) 0.2 wt.-% FSN, and ( d ) 0.3 wt.-% FSN.…”
Warm mix asphalt (WMA) is gaining increased attention in the asphalt paving industry as an eco-friendly and sustainable technology. WMA technologies are favorable in producing asphalt mixtures at temperatures 20–60 °C lower in comparison to conventional hot mix asphalt. This saves non-renewable fossil fuels, reduces energy consumption, and minimizes vapors and greenhouse gas emissions in the production, placement and conservation processes of asphalt mixtures. At the same time, this temperature reduction must not reduce the performance of asphalt pavements in-field. Low aging resistance, high moisture susceptibility, and low durability are generally seen as substantial drawbacks of WMA, which can lead to inferior pavement performance, and increased maintenance costs. This is partly due to the fact that low production temperature may increase the amount of water molecules trapped in the asphalt mixture. As a potential remedy, here we use fumed silica nanoparticles (FSN) have shown excellent potential in enhancing moisture and aging susceptibility of asphalt binders. In this study, asphalt binder modification by means of FSN was investigated, considering the effects of short-term and long-term aging on the rheological, thermal, and microstructural binder properties. This research paves the way for optimizing WMA by nanoparticles to present enhanced green asphalt technology.
“…Calcium exhibits a dull grey-silver appearance (Habte et al, 2019) . In addition to various biological and industrial usages as an alloying agent (Habte et al, 2019;Shen et al, 2019). CaO NPs, nanodots or nanopowders are cubic or hexagonal high surface area particles (Hussein et al, 2020) .…”
A LIBS technique was used to investigate the antibacterial activity of calcium oxide nanoparticles (CaO NPs). CaO NPs were prepared using a Q-switched Nd: YAG pulsed laser with a fundamental wavelength of 1064 nm at different energies (400-600 mJ) and constant frequency (6 Hz). A calcium powder sample was prepared after being pressed into a disc with a diameter of 1 cm. Analyzing X-ray diffraction (XRD) showed the crystalline structure of CaO NPs, crystalline size was 30.99±2 and 34.20±2.2 nm for laser energy 500 and 600 mJ. (FE-SEM) to reveal the topography of produced CaO NPs, the results showed a homogenous compact and dense surface with the formation of CaO NPs like flakes, cubes, and tubes. Atomic force microscopy (AFM) has shown that the CaO NPs were nanoscale and had a coordinated surface structures. The results also revealed the stabilizing zeta potential of the prepared CaO NPs, average (ZP) -18.3±1.6 mV in 600 mJ and -8.8±2.3 mV for 500 mJ. Different laser energies used in preparing CaO NPs resulted in the varying killing of the number of bacteria Klebsiella pneumoniae and Staphylococcus aureus bacteria. Complete bacterial inhibition or cell growth inactivation was found when the laser energy prepared for the CaO NPs was 600 mJ.
“…Considering that the poor stability properties of polymer-modified material requires to be further enhanced, and the polymers are more difficult to decompose and result in environmental pollution when they are wasted, the fiber modified materials, especially inorganic fibers, are the more favorable modifiers and are commonly applied [6]. The addition of fibers does not only improve the properties of asphalt binder by adsorbing asphalt binder to avoid the bleeding of asphalt pavement in summer, but also improves the engineering properties of asphalt mixtures including viscoelasticity, dynamic modulus, moisture susceptibility, creep compliance, rutting resistance, and freeze-thaw resistance [7,8]. Thus, the service life of asphalt pavement can be prolonged for these benefits.…”
Fiber-reinforced asphalt mixture has been widely used in pavement engineering to not only prevent asphalt binder leakage but also improve engineering properties of asphalt mixture. However, the research on three key parameters, namely fiber type, fiber length, and fiber content, which significantly affect the performance of fiber-reinforced asphalt mixture, have seldom been conducted systematically. To determine these three key parameters in the support of the application of fibers in mixture scientifically, three commonly used fibers were selected, basalt fiber, polyester fiber, and lignin fiber, and the testing on fibers, fiber-reinforced asphalt binders, and fiber-reinforced asphalt mixtures was conducted afterwards. The results showed: the favorable fiber type was basalt fiber; the favorable basalt fiber length was 6mm; the engineering properties including high temperature stability, low temperature crack resistance, and water susceptibility were clearly improved by the added basalt fiber, and the optimum basalt fiber content was 0.4 wt.%. The obtained results may be valuable from a practical point of view to engineers and practitioners.
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