The Effect of Cow Dung Ash as A Filler on The Mechanical Characteristics of Hot Mix Asphalt

Highway pavements are being exposed to increasing traffic loads and severe environmental conditions, resulting in reduced service life. A lot of studies have been conducted to modify asphalt by using different materials, especially to replace the ordinary filler. Because the behaviour of the hot asphalt mix is influenced by the fillers. The use of unusual materials as fillers in asphalt mixes can help to improve the mix’s characteristics. As a result, this study uses cow dung ash materials with various replacement ratios as fillers to investigate the mechanical properties of asphalt. In the asphalt mix, a replacement percentage of limestone (0%, 10%, 20%, 30%, 40%, 50%, 60%, 80%, and 100%) was utilized. After that, various tests were performed such as Marshall stability, Marshall flow, voids in mineral aggregate, theoretical maximum specific gravity, air voids. The results revealed a significant improvement in the asphalt mix’s behaviour, as well as an increase in the replacement percentage. According to the findings, the 50% replacement rate has the highest Marshall stability which is equal to 11.11 with a 33.5% rise and the lowest flow of 3 with a 17.83% decrease when compared to the reference mix. As a result, cow dung ash can be used as a filler to modify the mechanical properties of the asphalt mix.

Rheological Characteristics of Tire Rubber-Modified Asphalt following Thermal Variation

In recent years, due to the development of the automobile industry, there are more and more waste car tires, and the reuse of waste tires has become an urgent problem to be solved. In this study, the crushed rubber of waste automobile tires is used to modify asphalt to prepare rubber-modified asphalt, which can not only solve the problem of using waste tires but also effectively improve the performance of asphalt pavement. This study defines four modified asphalts with different rubber powder content, which are defined as 1#, 2#, 3#, and 4#, respectively. The performance difference between the four modified asphalts and the base asphalt was compared through experiments to illustrate the advantages of rubber-modified asphalt. The four selected rubber asphalts and base asphalt are subjected to the viscous toughness test, apparent viscosity test, DSR test, and BBR test to determine the high- and low-temperature characteristics of rubber asphalt. The analysis of experimental data shows that rubber-modified asphalt can effectively improve the low-temperature performance of the asphalt, make the asphalt have better toughness, and also improve the high-temperature shear resistance of the asphalt. Finally, it is determined that adding 10% rubber powder to the base asphalt has the best effect.

Study on Storage Stability of Activated Reclaimed Rubber Powder Modified Asphalt

The purpose of this research was to make full use of waste lubricating by-products (LBP) and reclaimed rubber powder (RR) to modify asphalt by a one-pot approach, so as to achieve the dual purpose of solving the poor storage stability of reclaimed rubber powder modified asphalt (RRMA) and the realization of solid waste recycling. A variety of characterization techniques were performed to analyze storage stability, conventional properties and microstructure of LBP-activated reclaimed rubber powder modified asphalt (Blend). Fourier transform infrared spectroscopy illustrated that not only the chemical composition of LBP was very similar to that of asphalt, but also the activation of LBP improved the compatibility of RR with asphalt and enhanced the storage stability of Blend. Fluorescence spectrum and scanning electron microscopy results indicated that the RR without LBP activation was aggregated and dispersed as blocks in asphalt, while the LBP activated RR was uniformly dispersed in the asphalt phase. The segregation test demonstrated that Blend exhibited outstanding storage stability, in which the softening point difference was within 2.5 °C and the segregation rate was −0.2–0.2. In addition, the conventional properties of Blend have been significantly improved, especially in penetration and ductility. More importantly, the short-term aging results demonstrated that, compared with RRMA, Blend possessed excellent anti-aging performance.

Performance of Modified Asphalt Binder with Tire Rubber Powder

The two major distresses associated with flexible pavement are rutting deformation and fatigue cracking in world highways. This is mainly because of the increasing load and higher tire pressure of vehicles which are applied to highway pavements today. At the same time, the asphalt containing neat binders does not always performed as expected. As a consequence, these distresses reduce the design life of the pavement and increase the maintenance costs tremendously. Therefore, in order to minimize the distresses and increase the durability of asphalt pavement, there is need to improve the performance properties of neat asphalt binders. Many researchers reported that using different types of polymer to modify the asphalt binder could be a solution to minimize the distresses occurred in asphalt pavement and improve the overall performance of the pavement. Disposal of waste tires is a serious environmental concern in many countries. Several attempts were made in the past to modify asphalt binder using tire rubber powder to improve the performance of neat asphalt binders. It is believed that the use of Tire Rubber Powder (TRP) as an additive in the modification of asphalt binder can improve the binder performance properties, increase the durability of the pavement, and reduces the waste disposal problem. This study aims to review the previous studies conducted on the use of tire rubber powder in the modification of asphalt binder. It was observed that addition of tire rubber powder to the asphalt binder enhances the properties of modified binder. It was found that an increase in the percentage of tire rubber powder causes an increase in rutting factor (G*/sinδ) and decrease in fatigue factor (G*sinδ) indicating higher resistance against rutting and fatigue cracking. In addition, the use of tire rubber powder to modify asphalt binder is considered as a solution to enhance environmental and economic sustainability of pavements.

Impact of Rubber Modifier on the Rheological Properties of Asphalt

Using crumb rubber to modify asphalt binder can not only improve the binder properties, but also shows environmental and economical advantages. To evaluate the function of the RM modifier in binders, physical properties and rheological properties were investigated. Specifically, the high and low temperature sweep methods was used to investigate influence that the RM on rheological properties of binders. Results showed that binder modification using the RM produces significant increase in both physical properties and rheological properties. Consequently, enhanced resistance to permanent deformation, increased low-temperature cracking and reduced temperature sensitivity can be expected in RM binder.

Study on Anti-Ultraviolet Radiation Aging Property of TiO2 Modified Asphalt

In order to decrease the disadvantageous effect of ultraviolet light to asphalt, nano-scaled TiO2 was selected as modifier to modify asphalt. The photooxidation properties of the modified asphalt were examined in a home-made ultraviolet radiation environment box. By comparing the before and after performance indexes of asphalt, the anti-photooxidation aging property of modified asphalt and the blank asphalt were studied. And the results showed that the sample of 5% TiO2 modified asphalt possesses more stable ductility and smaller softening point changing ratio.TiO2 doping can actively enhance the photooxidation properties of asphalt and TiO2 modified asphalt is capable of resisting photooxidation aging.

Microstructure and Properties of Nanoclay Reinforced Asphalt Binders

In this paper, sodium bentonite (BT) and organically modified sodium bentonite (OBT) are used to reinforce and modify asphalt binder. The microstructures of the reinforced asphalt binders are investigated using transmission electron microscopy (TEM) and wide angle X-ray diffraction (WAXD). Two models for the microstructure of the BT and OBT modified asphalts are suggested considering the colloidal structure of the base asphalt binder. The physical properties of the modified asphalt binders were studied.

Study on the Freeze-to-Crack Test of Asphalt Modified by Waste-PE in Packing

The purposes of this study are to modify asphalt by retrieved waste-PE in packing (WPP) and to investigate the low temperature properties of the modified asphalt. The traditional testing methods such as low temperature ductility, low temperature penetration degree, penetration or Fraass breaking point think that PE can not improve the low temperature properties of asphalt effectively, while this study adopts a new method to test the low temperature properties of WPP modified asphalt through the freeze-to-crack test. The result indicated that, after the modification, the low temperature properties of asphalt are improved, which coincides with the fact. And the improvement of the low temperature properties can be explained by the function of Shear yield and crack pinning.