Warm-Mix-Asphalt (WMA) allows aggregates to be coated with asphalt binder at a temperature lower than the Hot-Mix-Asphalt (HMA) temperatures by using additives that make the asphalt mixtures more workable and the asphalt binder viscosity reduced. Due to the cost and environmental advantages of WMA, it is now more frequently employed in the mixtures of asphalt pavement. WMA with two percentages of zeolite (0.3% and 0.5%) is used in this research. The optimum asphalt content of WMA mixtures has a lower value compared to the HMA mixture. According to Marshall Stability’s findings, the HMA has a higher value of stability, whereas the WMA mixtures for both percentages of zeolite have a lower value of stability. WMA mixture with 0.5% zeolite has a higher Marshall Flow value, which is followed by zeolite at 0.3% and the lower value of flow was for HMA. The resilient modulus for both HMA and WMA was determined. The findings indicate that, for the two percentages of zeolite, the resilience modulus of the WMA mixtures was lower than that of the HMA. Additionally, the findings indicate that the WMA has a high potential resistance against rutting that competes with the HMA mixture.

The bituminous material performance is affected basically by the prevailing temperatures. The mechanical properties of these materials can vary significantly with the changes in the temperature magnitude. Hot mix asphalt (HMA) is a visco-elastoplastic material, so the pavement structural capacity is affected by the temperature variations. To determine the characteristics of the strength of the flexible pavement rationally, the prediction of the distribution of temperature in HMA pavement layers is a must. Heavy loadings subjected to highways and roads can cause serious deterioration to the HMA pavements. In this research, the temperature for three thicknesses of asphalt pavement structure was measured, and the air temperature to predict a model explains the relationship between the temperature and the depth of the pavement structure. The suggested model was successfully validated utilizing the data from three depths of asphalt pavement structure and the temperature on the surface of the asphalt pavement. The developed model consists of two independent variables, which are the depth within the pavement and ambient air temperature. The predicted model will be useful for the pavement designers those in need to predict the temperature of the profile of pavement to determine the engineering characteristics of field pavement.

It is known to researchers in the field of road construction and development. Three types of pavement are rigid, flexible, and composite paving. The composite pavement consists of a layer of flexible pavement on top of which a layer of rigid pavement is placed or vice versa. All of these types have advantages in addition to disadvantages that affect road performance on the one hand and user convenience on the other. About 50 years ago, work began establishing a type of pavement characterized by its semi-flexible performance, which combines rigid pavement's rigidity and flexible pavement's flexibility. It is called semi-flexible pavement and grouted macadam in some sources. It consists mainly of an open-graded asphalt mixture in which the percentage of air voids ranges from (25 to 35%), and in some sources, it is mentioned that it ranges between (20 to 28%) grouted with a high-performance cementitious material. Work began on this type of pavement in the sixties of the last century. However, there is no approved specification for its design, as its design methods differ according to the researcher's vision. This scientific paper aims to facilitate the way for new researchers in this field by knowing the basic stages of semi-flexible pavement design and presenting the existing design methods and what is required for laboratory tests to evaluate the performance of the completed pavement design. It was found that the performance of semi-flexible paving depends mainly on the bonding between its components, as it is considered a composite material. For this reason, the direction in the future may be to study the bonding between asphalt and cement, in particular, as they are two basic materials in their composition.

This study investigates the performance improvement of asphalt binders through the incorporation of two polymers, polyvinyl chloride (PVC) and styrene–butadiene–styrene (SBS), with asphalt grade (60–70), to address the growing demand for durable and climate-resilient pavement materials, particularly in areas exposed to high temperatures like Iraq. The main objective is to improve the mechanical characteristics, thermal stability, and workability of typical asphalt mixtures to extend pavement lifespan and lessen maintenance costs. A thorough set of rheological, physical, morphological, and workability tests was performed on asphalt binders modified with varying content of PVC (3%, 5%, 7%, and 9%) and SBS (3%, 4%, and 5%). The significance of this research lies in optimizing binder formulations to enhance resistance to deformation and failure modes such as rutting and thermal cracking, which are common in extreme climates. The results indicate that PVC enhances performance grade (PG), softening point, and viscosity, although higher contents (7% and 9%) exceeded penetration grade specifications. SBS-modified binders demonstrated marked improvements in softening point, viscosity, and rutting resistance, with PG values increasing from PG64-x (unmodified) to PG82-x at 5% SBS. Fluorescence microscopy confirmed optimal polymer dispersion at 5% concentration for both SBS and PVC, ensuring compatibility with the base asphalt. Workability testing revealed that SBS-modified mixtures exhibited higher torque requirements, indicating reduced workability compared to both PVC-modified and unmodified binders. These findings offer valuable insights for the design of high-performance asphalt mixtures suitable for hot-climate applications and contribute to the development of more durable and cost-effective road infrastructure.

The release of greenhouse effects into the environment is one of the factors contributing to pollution connected to the development of transportation infrastruc The release of greenhouse effects into the environment is one of the factors contributing to pollution connected to the development of transportation infrastruc

Rutting is the most common distress that most Iraqi asphalt pavements suffer from it. Asphalt binders are modified by using additives and polymers to enhance their physical qualities and fulfill the performance demands. Polyphosphoric acid (PPA) has been used in many countries to enhance the physical and mechanical characteristics of asphalt binders and mixtures that can improve the performance of asphalt pavements. In this paper, evaluation of the Iraqi asphalt binder and mixtures performance by using three percentages of Polyphosphoric acid (PPA) (0.4, 0.8, and 1.2) percent by asphalt binder weight and added to (60-70) penetration grade asphalt binder to show the applicability and suitability of using PPA in asphalt pavement in Iraq. Original asphalt binder and modified are subjected to traditional tests which are penetration, ductility, softening point, and viscosity. Results show better performance and enhancement of the physical properties of the modified binder. Other tests are Marshall Stability and wheel track tests. The results of the addition of PPA to the asphalt mixture show increases in the Marshall Stability and enhance the performance of the asphalt pavement mixtures. The wheel track test is applied to the original and modified mixture at two test temperatures 40 ?C and 50 ?C and the results show a decrease in the rut depth when the percentages of PPA increase. It is concluded that %PPA addition will enhance the performance of the Iraqi asphalt pavement and the mixture will be more rutting resistant, especially in high-temperature weather.