Warm-mix asphalt (WMA), which reduces the production temperatures (mixing and compaction), while maintaining the advantages of hot-mix asphalt (HMA), is becoming an attractive paving material. In this study, rheological properties of two commonly used performance grade (PG) binders (PG 64-22 and PG 70-28) were evaluated, with and without Sasobit and Aspha-Min additives. For PG 64-22, 2%, 3%, and 4% Sasobit additive reduced the mixing temperature of the pure binder from 163°, C to 147°, C (i. e., by 16°, C). In case of the PG 70-28, the reductions are 10°, C, 12°, C and 13°, C, respectively, for 2%, 3%, and 4% Sasobit additive. No significant decrease in mixing temperature by the Aspha-Min additive was observed in using the rotational viscometer. Evaluation of the binders on the basis of G*/sin () demonstrates no negative effect on high-temperature grading due to high-temperature viscosity reduction. With the addition of 4% Sasobit additive, the high-temperature binder grading of PG 64 (actually PG 65) increases to PG 69, while 4% Sasobit additive improves the PG 70 (actually PG 75) to PG 80. No significant changes in grading were observed with the addition of the Aspha-Min additive. In fact, reduction in binder viscosity and improvement in binder grading with-out increasing the viscosity indicate two-way reductions (both direct and indirect) in production temperatures by the Sasobit additive. Finally, the Sasobit additive is found to decrease the asphalt pavement analyzer rut depths significantly, and these rut depths correlate well with the rutting factor G*/sin(). It was also observed that rutting potential decreases with decreasing mixing and compaction temperatures. Comparatively, a smaller reduction in rut depths was observed by adding the Aspha-Min additive.

Despite the high application and proper properties of bitumen in Consumptions of road construction، damages and disadvantages of asphalt mixing are created. Including rutting، cracking، necessitate the repair of bitumen that are used in road construction with additives. Some additives reduce the hardening of the bitumen by reducing mixing and compaction temperature، resulting in a modification of the mixing behavior of the asphaltic against the loads. in addition، will reduce air pollutants and energy consumption. Therefore the aim of this research is to study rheological properties of modified bitumen via investigating and comparing sasobit، paraffin wax with unmodified bitumen as well as their composition considering the effect of this additive on aging and performance temperature. For this purpose، base bitumen (AC 60/70) was selected and used as a laboratory method based on common bitumen tests، which including penetration degree and، softening point، and Sharp tests including Dynamic shear rheometer Rotational viscosity and aging tests. The results of the experiments indicated the effectiveness of the mentioned waxes in increasing the bitumen efficiency by reducing the viscosity. In this case، the mixing and compaction temperature can be reduced، which reduces the aging and stiffness of the bitumen. Also the use of combination sasobit waxes and paraffin can improve the high performance of bitumen compared to the samples which consist of paraffin. By comparing the effects of this combination with other waxes along with considering to the cost and effectiveness degree، it is possible to have good choice for improving properties and behavior of bitumen.

Now days, reclaimed asphalt pavements are used in the production of asphalt mixtures. The use of this material has too many economic and environmental benefits. Beside, warm mix additives are materials that they reduce production temperature of asphalt mixtures and improve their workability in the constructed pavements. There is always a question that “, what are the effects of reclaimed asphalt pavement and warm additive on the mix design parameters of asphalt mixtures? ”,In this research, the simultaneous effects of reclaimed asphalt pavement and a warm additive named Sasobit on the technical properties of asphalt mixtures were evaluated. For this purpose, an experimental plan was designed based on the response surface method for reclaimed asphalt pavement (from 0 to 50%), asphalt binder content (from 4 to 6%) and Sasobit content (from 0 to 3%). Then, the volumetric and strength properties of these mixtures were determined and compared with the Iranian pavement code criteria. Obtained laboratory results showed that an optimum point for fabrication of asphalt mixtures containing reclaimed asphalt pavement is a mixture with 4. 6% asphalt binder, 12% reclaimed asphalt pavement and 3% Sasobit additive. Also, increasing the amount of the Sasobit showed that it increases the value of the Marshal strength, asphalt unit weight of mixtures and it reduces its air voids.

One engineering solution to reduce the amount of rubber waste is the use of rubber powder in the production of asphalt mixtures to enhance their performance. However, the high mixing temperature of rubber powder and asphalt necessitates the implementation of solutions that can simultaneously reduce the energy required for mixing and improve the performance of rubberized asphalt. One approach that researchers have explored in recent years is the use of Warm Mix Asphalt (WMA), which requires mixing temperatures that are 10 to 30 degrees lower than those of Hot Mix Asphalt (HMA). Among the materials that can lower the mixing temperature of rubberized asphalt is Sasobit. Although researchers have examined asphalt mixtures containing rubber powder and Sasobit, the moisture sensitivity of this type of mixture has not been specifically investigated. This study aims to assess the moisture sensitivity of asphalt mixtures containing rubber powder and Sasobit using two amounts of 8% and 16% rubber powder and 1%, 2%, and 3% Sasobit. Two mixing temperatures of 150 and 130 degrees Celsius were employed to observe the differences between warm and hot mixtures. The samples underwent Marshall stability and flow tests, resilient modulus, dynamic creep, and moisture sensitivity tests (indirect tensile strength, saturated to dry compressive strength ratio, and Texas boiling test). The results indicate that Warm Mix Asphalt technology can be utilized in rubberized asphalts,however, due to the increased moisture sensitivity of the mixture with higher percentages of rubber powder at lower mixing temperatures, high percentages of rubber powder should be avoided. According to the findings, in rubberized asphalt mixtures containing 8% and 16% rubber powder, the mixing temperature can be reduced to 150 degrees Celsius by adding 3% Sasobit, but lowering the temperature to 130 degrees is not recommended due to its significant impact on moisture sensitivity.

It is very common to modify rubber bitumen with warm asphalt waxes such as Sasobit, also the use of cellulose fibers for tensile strength and better strain energy absorption power than other additives has attracted the attention of researchers. This research used cellulose fibers coated with Fishertraps wax (Sasobit) in proportions of 1,3, and 5% as an additive in bitumen with 15% rubber powder. So that modified bitumen can be used to improve strain energy absorption and bitumen shedding in asphalt mixtures with open-graded and low density or to improve the index of resistance against rutting in higher-density mixtures. The results of the investigation of rheological properties indicate that the addition of the mentioned fibers to rubber bitumen, in addition to reducing stiffness, increases its resistance to rutting in both unaged and short-term aged samples. The results show that the upper-performance limit of unaged pure bitumen 22-64, with the presence of 15% rubber powder and improved fibers, for example, adding 5% fibers to bitumen with 15% rubber powder increases the upper limit of bitumen performance up to 94 degrees Celsius. It increases the degree. Also, the performance of short-term aged and non-aged rubber bitumen is similar, but short-term aging of bitumen reduces the effect of fibers. Also, the addition of fibers causes an increase in the modulus of complexity in the middle temperature and better performance in returning from the multi-stress level in the fracture temperature. This better performance makes the rubber powder bitumen-containing fibers perform better against rutting failure at the highest operating temperature.

In this paper, the effect of asphalt overlays, which were reinforced with geogrid, modified by sasobit and combination of them on rehabilitation of reflective cracking, is studied. The laboratory tests were conducted under dynamic loading in bending mode to investigate reflective cracking retardation compared to reference samples. The results illustrated that in a certain range of variables, temperature variations and sasobit percentages are the most effective parameters on fatigue life and other responses. Another effective variable was the type of interlayer in asphalt slabs. Furthermore, it has been found that the combination of samples (modified by sasobit, reinforced with geogrid and a 3cm sand asphalt layer) (1SP. G. SA & 2SP. G. SA) had a better performance such as improving fatigue life and reducing crack propagation in all loading and temperature conditions compared to the reference samples. Based on the image processing results, the process and shape of crack growth vary greatly at different temperatures. Generally, at low temperatures (20 ° C) and frequencies the cracks grow from bottom to top and the width of them get smaller. However, with increasing the temperature and loading frequency, the top down cracks are also observed, which is due to the reduced resistance of the asphalt resulting from the reduction of adhesion and the fastening between the aggregate and bitumen.

The implementation of polymer modification on bitumen performance at low temperature is significantly compromised by the breakdown of styrene-butadiene rubber (SBR) polymer during bitumen mixing operations. The effectiveness of using waste edible oil/Sasobit (Sasobit/WCO) as a hot additive mixture has been demonstrated in reducing the adverse effects of thermal aging on bitumen modified with Stysene Butadiene Rubber Bitumen (SB) while maintaining the initial performance of the bitumen. However, few studies have been conducted to further investigate the rheological properties and aging resistance of SB bitumen modified with Sasobit/WCO blends. In this research, three additives - Sasobit, WCO, and Sasobit/WCO composite - were selected on the physical and rheological properties of SB, and they were investigated and also evaluated in those mixtures prepared. In addition, using dynamic shear rheometers (DSR) and bending beam rheometers (BBR), this warm mixture was evaluated on performance grade (PG) and aging resistance SB. According to the results, Sasobit/WCO composites perform better than Sasobit and WCO in reducing the preparation volume. Sasobit/WCO also improves the performance of SB in high and low simultaneously. Compared to hot asphalt mixtures, the addition of Sasobit/WCO reduces the preparation of bitumen mixtures by 19 °C, which contributes to the lowest negative aging temperature on SB performance. In addition, the addition of Sasobit/WCO composite can improve the SB mixture against thermal cracking. After the introduction of Sasobit/WCO, the high PG of SB increased by two grades regardless of whether the effect of warm mixing was taken into account. With the addition of Sasobit/WCO, the acceptability of SB against short-term aging increased.

The importance of environmental protection in the construction of pavement has led to that in recent years the warm mix asphalt technology as a new method has always been to reduce environmental damage and reduce the cost of manufacturing and it recognizes as an environment-friendly technology, and this be used. This technology has the advantage of reducing the temperature of mixing and compaction and other benefits, has a weak point of moisture susceptibility and rutting. The use of anti-stripping additives is one of the ways to improve the moisture resistance of these types of asphalt mixtures. This research was conducted with the aim of using different percentages of Gilsonite as a modifier in warm mix asphalt (WMA) and also to investigate its effect on functional properties especially the moisture sensitivity of warm mix asphalt. In order to investigate the effect of Gilsonite on reducing moisture sensitivity, the Lottman modified test were used and also, the resilient modulus and dynamic creep testing were used to investigate the performance properties, which the results showed that Gilsonite due to its inorganic compounds increased bond adhesion of bitumen and aggregate. Also, it has the characteristics of an anti-stripping material and could be causing to increase the life of the warm mix asphalt against moisture damage in wet areas. furthermore, the results of the dynamic creep test indicated that Gilsonite significantly increased the asphalt mixture resistance against the rutting and it was an appropriate additive to prevent the rutting of asphalt mixture in the tropical region (south of the country).

In this study, the effect of the use of two WMA additive sasobit and rheofalt additives on the fatigue properties of the asphalt mixes was evaluated. For this purpose, laboratory samples containing 100 % RAP and a hot mixture were constructed using RAP material, which is separated from the bitumen. The recycled mixtures include a hot recycling sample and three warm (1 non-additive sample, 1 sample containing sasobit additive, 1 containing rheofalt additive). In this research, different experiments such as indirect tensile strength, resilient modulus and fatigue are investigated. Fatigue test was performed on four-point bending test with constant strain level at three levels 600, 800 and 1000 micro-strain with sinusoidal loading. The fatigue life of specimens was evaluated based on a 50 % reduction in the initial hardness modulus. The results showed that sasobit and rheofalt additives had a positive effect on the compression and functional properties of the blends. In the performance of fatigue and low-temperature cracks, the hot mixture was better in spite of the positive effects of additives.