Effect of Hot Glue Additive on the Rheological Properties of Asphalt Cement and Mixtures Performance

In general, the physical and rheological properties of asphalt binder are directly affecting the resistance of asphalt mix to the permanent deformation (rutting), water damage, and thermal cracking. The degradation in these properties leads to severe distresses that appear in the pavement and, consequently, make the repair and maintenance very expensive. Since the modified-asphalt cement may help to minimize such aforementioned distresses, this research is established for this purpose. It aims to investigate the physical and rheological properties of modified-asphalt cement with silicone, dense silicone rubber, and ethylene propylene diene monomer rubber. Five contents for each type of hot glue are investigated; 0.4, 0.8, 1.2, 1.6, and 2% of the asphalt cement weight. Conventional asphalt cement tests such as penetration, softening point, dynamic viscosity, and ductility tests are conducted to evaluate the hot glue-modified asphalt cement properties. Moreover, the Marshall and indirect tensile strength tests are conducted to examine the effect of hot glue on the performance of the asphalt mixtures at concentrations of 0.8 and 1.6% of the asphalt cement weight. The results show that the hot glue-modified asphalt cement leads to an increase in the hardness and consistency, and a reduction in the temperature susceptibility of asphalt cement. These features lead to better Marshall stability and tensile strength ratio, as compared with the standard asphalt cement mixture

Influence of Natural Fibers on the Performance of Hot Mix Asphalt for the Wearing Course of Pavement

Cracking in the flexible pavement is a serious problem that reduces the service life of the roads pavement unless they are treated with great care. Since flexible pavement is very weaker in tension than in compression, it is usually necessary to consider the tensile stresses and some type of additives to improve asphaltpavement performance, and one of the most effective ways of improving asphalt pavement performance is to reinforce asphalt mixtures by incorporating natural fibers. The main objective of this study is to use palm fiber, which is locally available, in hot mix asphalt mixtures. To achieve this objective, the Marshall test and indirect tensile strength test were conducted on four asphalt mixtures with different types of natural fibers (Coconut, Corn, Palm, and Sisal), added in varying percentages 0.1, 0.2, 0.3, 0.4, and 0.5% and different lengths of fiber 0.5, 1, 1.5, and 2 cm. Based on the analyzed results, it can be concluded that the use of palm fiber increased the Marshall stability by 20% as compared with the conventional mixture and raised up the retained tensile strength ratio up to 92%. Finally, the use of 0.2% content of natural fiber at 1.5 cm length gave a better performance for the mixtures

Identification of P53 Tumor Suppressor Gene Alterations in Human Glioma Using Sscp-Pcr Technique.

The P53 is the most commonly altered gene in cancers, which is located on chromosome 17p. Because of it is important role in the cell cycle it considered as the guardian of the genome that maintains genome integrity. In this study we analyzed DNA from 15 surgical specimens of human glioma for mutations in the p53 gene along exons 6-9 using single-strand conformation polymorphism analysis of polymerase chain reaction product (PCR-SSCP). The frequency of P53 gene mutation in gliomas examined was 26.6% (4 of 15). All 4 mutated cases were in exon 6 and no mutation was observed in exon 7,8 and 9. The results suggest the involvement of P53 gene mutation in Glioma and it might play an important role in the tumorigenesis process of patients with brain tumor in preliminary study in Duhok province