Perviz Ahmedzade

Evaluation of steel slag coarse aggregate in hot mix asphalt concrete

This paper presents the influences of the utilization of steel slag as a coarse aggregate on the properties of hot mix asphalt. Four different asphalt mixtures containing two types of asphalt cement (AC-5; AC-10) and coarse aggregate (limestone; steel slag) were used to prepare Marshall specimens and to determine optimum bitumen content. Mechanical characteristics of all mixtures were evaluated by Marshall stability, indirect tensile stiffness modulus, creep stiffness, and indirect tensile strength tests. The electrical sensitivity of the specimens were also investigated in accordance with ASTM D257-91. It was observed that steel slag used as a coarse aggregate improved the mechanical properties of asphalt mixtures. Moreover, volume resistivity values demonstrated that the electrical conductivity of steel slag mixtures were better than that of limestone mixtures.

Irradiated Recycled High Density Polyethylene Usage as a Modifier for Bitumen

AbstractThis paper studies the use of recycled high-density polyethylene (HDPER) obtained from waste bottle crates as modifier in bitumen. Post-consumer HDPE was irradiated in order to casue a chemical interaction with bitumen. Accordingly, Fourier transform infrared (FTIR) spectroscopy was employed to determine the effects of the electron beam irradiation on the chemical structure of HDPE. Differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), and fluorescent microscopy results signified that there might be a chemical interaction between electron beam irradiated HDPE (HDPERe) and bitumen. Physical and rheological tests were applied to the binders to investigate the effects of HDPERe polymer on the performance of the bitumen. Fundamental rheological tests performed using a dynamic shear rheometer (DSR) and bending beam rheometer (BBR) indicate that the HDPERe modifier provides a clear improvement in temperature susceptibility of bitumen. Thus, the HDPERe modification produces enhanced ...

Effect of Gamma-Irradiated Recycled Low-Density Polyethylene on the High- and Low-Temperature Properties of Bitumen

This paper describes polymer modification of bitumen with gamma-irradiated recycled (γ-) low-density polyethylene. The recycled low-density polyethylene () was obtained from greenhouse films exposed to sunlight at least one year. The surface of the was treated by gamma beam irradiation that provided formation of free radicals and some functional groups that may contribute to the creation of strong chemical bonds between polymer modifier and bitumen. Five different samples of bitumen/γ- compositions with the modifier content, wt. %: 1, 3, 5, 7 and 9, were prepared. The effects of the γ- on original and aged bitumen were investigated by means of morphological, chemical, and physical testing program, including FTIR spectroscopy, conventional tests, rotational viscosity (RV), dynamic shear rheometer (DSR), and bending beam rheometer (BBR) tests. Superior performing asphalt pavements (Superpave) specifications were used to analyze mechanical test results as well as to determine the performance grades (PG) of the binders. Optimum usage of the γ- as modifier in bitumen were suggested after testing program. The results reveal the stiffening effect of the γ- on bitumen that provide enhanced temperature susceptibility and also promise better performance grades (PG) with γ- polymer modification.

Use of maleic anhydride grafted recycled polyethylene treated by irradiation in bitumen modification

Most of the polymers currently used as additive in bitumen are not economically attractive. Thus, employing recycled materials in flexible highway instead of virgin ones has become a fundamental case for researchers especially in terms of cost efficiency and environmental awareness. To date, many studies have been made to investigate using of recycled polymers in bitumen and generally improved mechanical properties of bitumen were determined. This paper aims to present the modification of bitumen by maleic anhydride (MAH) grafted recycled low density polyethylene treated by irradiation (g-LDPEr-g-MA). Maleic anhydride was dissolved and mixed with recycled polyethylene which was proved by the Fourier infrared (FT-IR) spectrum. Subsequently, pre-treated LDPEr granules were subjected to gamma irradiation doze of 10kGy to provide formation of free radicals and some functional groups which can contribute to creation of strong chemical bonds between polymer modifier and bitumen. Six different binders (one base and five modified) were prepared to investigate the effects of g-LDPEr-g-MA modifier on properties of bitumen. The dispersion of g-LDPEr-g-MA modifier in bitumen was examined by florescent microscope. Conventional tests and rotational viscosity test was used to determine physical properties of bitumens. Complex shear modulus (G*) and phase angle (δ) of base and modified bitumens were measured by means of dynamic shear rheometer (DSR) for different traffic speed and in-service pavement temperature. Tests results reveal that a gradually increment in g-LDPEr-g-MA modification leads to a decrease in penetration and an increase in softening point. According to DSR test results, g-LDPEr-g-MA modifier provides an increased rutting parameter. Thus, flexible pavement could become more resistant against permeant deformations by g-LDPEr-g-MA modification.