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Fatigue, creep and erosion are among the factors which destroy the asphalt mixture and modifying the asphalt binder via additives such as crumb rubber, sulfur, carbon, as well as natural and synthetic polymers has been done in order to improve the strength of asphalt mixture. Knowledge in the field of nanotechnology along with its capability and attractiveness for application as nanoparticles in different industries such as asphalt industry has attracted great attention in recent years. In this study, specific percentages of TiO2nanoparticles, namely 2, 4, and 6, were added to the asphalt binder as the nanocomponent. Done physical common tests such as penetration degree, softening point, flash point and viscosity of the base asphalt binder and modified asphalt binder, the bending beam samples composed of origin asphalt sample and modified asphalt sample with 4% TiO2nanoparticle were subjected in different micro strains to fatigue loads. Results of four point bending fatigue test showed that the addition of TiO2nanoparticles to the asphalt binder increased the fatigue strength in the asphalt samples. Modified asphalt binder is stiffer, more viscous than original asphalt binder and due to TiO2nanoparticles more temperature tolerance and load bearing capacity, modified Asphalt is more resistant under fatigue loads.

In this research, carbon black (CB) particles were produced from the pyrolysis of crumb rubber (CR), and nano-carbon black (NCB) was obtained from CB particles. A commonly used performance grade (PG) binder (PG 64-22) was modified with different dosages of CB and NCB particles. After the basic laboratory bitumen test, the penetration index and stiffness modulus of the modified bitumen were calculated. The cohesion and adhesion work between different combinations of modified bitumen and aggregates (quartzite, granite, limestone, and sandstone) were measured in the absence and presence of water. Results showed that the penetration index and stiffness modulus of the bitumen modified with CB and NCB particles increased, while the static contact angle decreased. Limestone and quartzite showed the lowest work of adhesion, whereas sandstone demonstrated the highest work of adhesion in wet conditions. According to compatibility parameter (CP) data, limestone and quartzite had the most compatible aggregates-bitumen structure. With the addition of higher CB and NCB percentages, the CP value depicted an increasing trend. Finally, according to two new statistical models, a direct relationship existed between the work of cohesion and stiffness modulus of the modified bitumen.

The use of carbon black (CB) obtained from recycling petrochemical waste in bitumen has been reported. In this research, petrochemical waste was recycled and micro-nano CB was produced. Bitumen known as PG64-22 was modified with 3, 5, 7 and 10 wt% of CB and 1, 3, 5 and 7 wt% of nano CB (NCB). NCB particles were evaluated using the scanning electron microscopy and dynamic light scattering test. Stiffness modulus changes of modified bitumen were investigated using the Radovskiy and Teltayev model. Contact angles of three probe liquids, namely water, formamide, and glycerol, were measured on the surface of modified bitumen. The surface free energy parameters like Lifshitz-van der Waals force, polar component and the work of cohesion and adhesion were defined. The results showed that CB and NCB particles increased the penetration index and stiffness modulus of modified bitumen. The total SFE increased more than 50% with 10% CB particles and more than 80% with 7% NCB particles. In addition, the compatibility ratio of limestone and quartzite was revealed to be more than that of granite and sandstone. The results also demonstrated that the wettability of bitumen modified with NCB particles were higher than those modified with CB particles and showed more compatibility ratio values. Moreover, four energy ratios variations of modified bitumen with CB and NCB particles indicated moisture damage performance improvement in the bitumen and aggregate mixes. Also, the results of the indirect tensile strength (ITS) test showed that CB particles in the bitumen led to less reduction of adhesion between bitumen and aggregate compared to the control mixture, leading to an increase in the resistance to moisture damage of asphalt mixture.

Rutting is considered as one of the major damages in asphalt mixtures. In this study, different types of nanoparticles such as TiO2, Al2O3, Fe2O3 and ZnO in different percentages were added to the base asphalt binder in order to decrease the rutting potential of hot-mix asphalt (HMA). In the first step, asphalt binder tests for characteristics such as penetration grade, ductility, softening point and viscosity were performed on the asphalt binder modified by the nanoparticles. Then, after preparing HMA samples, the static creep test was done at two stress levels at a specific temperature. Results of this study showed that using the nanoparticles improved the behavioural properties of the asphalt binder and decreased rutting in asphalt mix samples. Furthermore, scanning electron microscope images taken from the asphalt binder samples modified by the nanoparticles demonstrated that these nanoparticles were properly distributed in the asphalt binder space and had a positive effect on the rutting performance ...

One of the important characteristics of developing countries is strengthening and modernizing transportation networks including land paths. This is not possible without using modern technology, new materials and its additives. Roller compacted concrete (RCC) is a usable material in making pavement of roads. As the authors know the strength and composition of roller compacted concrete is different from concrete. In this study roller compacted concrete is assessed by specified percentage of basalt fibers, reinforced recycled polyethylene and executive notes of this concrete. Then provided samples are tested with regard to flexural, tensile and compressive strength. According to the results, strength parameters of reinforced roller compacted concrete have increased. So, with regard to reducing thermal fracture, increasing flexural and tensile strength, this composition can be introduced as one of the modern ways in making composite pavements with less implementing thickness and longer life-time than traditional methods.

Modification of the asphalt binder is one approach taken to improve Asphalt pavement performance. Rutting is one of the most important factors that could reduce the life of asphalt pavements.Nowadays, the application of nanotechnologyto achieve materials that are more resistant is expanding in asphalt pavement thatNano-TiO2is among the most exciting and promising classes of materials discovered recently. The purpose of this study is laboratory research on the effect of Nano-TiO2in improving Bitumen property and rutting resistance in Asphalt pavement under dynamic loading. For this purpose, the wheel-tracking test was carried outon ordinary and Nano-TiO2modified hot mix asphalt samples.The results illustrate that using Nano-TiO2in asphaltbinder samples cause to an improvement in ruttingdepth in comparison with theordinarymixtures.

Modification of the asphalt binder is one approach taken to improve aged pavement performance. To make the most of maintenance budgets, many agencies have resorted to the use of asphalt rejuvenators as an alternative to revive aging and brittle asphalt pavements. The purpose of this study is laboratory research on the effect of asphalt emulsion in restoring the original properties of aged asphalt pavement. For this purpose, the repeated load axial test is carried out on conventional asphalt samples and aged asphalt samples containing rejuvenator agents in different stress and rejuvenator percentage. Bitumen aged with RTFO according to ASTM-D2872 and the optimum bitumen of 5.5% were considered. The softening point and penetration tests, to examine the effect of rejuvenator in asphalt mixtures modification, On the basic, aged and modified aged bitumen were performed. The results represent that asphalt emulsion as a rejuvenator material in aged asphalt samples because of suitable performance improve aged asphalt permanent deformation resistance and aged bitumen Rheological property.

Recycling of bituminous mixes is extending worldwide with the aim of conserving natural resources and the environment. Rejuvenating agents are generally used in recycling processesin order to soften the aged binders in mixes. Cutback bitumens have been used in Iran mainly in preparing conventional cold mixes. However, the long term good performance of these cold mixes in various parts of the country has shown less hardening of these mixes, compared with conventional HMA mixes. In this research the application of a cutbackbitumen has been investigatedas a rejuvenating agent in mixes containing laboratory aged binders. A 60-70 penetration grade bitumen from Refinery of Tehran was aged under Thin Film Oven Testing (TFOT) conditions. Asphalt Concrete samples were prepared using TFOT aged and virgin binders. Additional samples were prepared using the aged binders together with various amounts of a slow curing SC-250 cutback bitumen from the above refinery. The compacted four inchdiameter samples were tested under static creep testing. The results showed promising effects of the cutback binder in rejuvenating the aged mixes. Based on the results of this study, a mix design criteria wasset for recycled mixes containing cutback bitumen as the rejuvenating agent.