Physicochemical, mineralogical, and thermogravimetric characterizations were carried out to assess the potential technological benefits of natural sand deposits from El-Oued district (eastern Algeria). The use of granulometric analysis, FTIR spectroscopy, X-ray fluorescence (WDXRF), X-ray diffraction (XRD), scanning electron microscope (SEM/EDX), and thermogravimetric (TGA) analysis was necessary to further highlight the main physical and chemical properties of the studied sands. The grain size distribution suggests fine-to-medium sands with a mean grain size ranged from 207 to 261 μm. However, the grain micro-texture features indicate aeolian nature of El-Oued sand, and the chemical analysis reveals that all samples contain a high ratio of silica (SiO 2 ) reaching 94% with low content of CaO, Al 2 O 3 , Fe 2 O 3 , Na 2 O, and K 2 O oxides, which reflects the siliceous nature of El-Oued sand. The mineralogy of the El-Oued sand consists mainly of α-quartz (≤ 93% SiO 2 ) with minor calcite (CaCO 3 ) and very small amounts of feldspar mineral. Furthermore, the crystallite size of Quartz in all sand samples was determined to be in the range of nanometric scale. Thermal analysis (TGA) showed that El-Oued sand was relatively stable upon 800 °C. These characteristics corroborate the interesting and promising uses of El-Oued sand in the industry and nanotechnology. KeywordsSand • Mineralogical and chemical characterization • α-Quartz • Rietveld refinement • Industrial applications

The near surface mounted technique has been used in recent years for the strengthening of reinforced concrete beams. It involves the insertion of strips or rods of carbon fibers reinforced polymers in grooves made previously in the concrete cover of corresponding surfaces, filled with epoxy adhesive for fixation. A parametric study was carried out based on pullout-bending tests in order to evaluate the influence of bond strength, concrete strength, bond length, type and configuration of strengthening on the pullout load, bonding stress, stiffness and failure mode. The influences of these parameters on the bond behavior between the three materials (concrete, epoxy adhesive and carbon fibers reinforced polymer) were evidenced and discussed.

This study is one of the first works which examined the assessment of heavy metal contamination of pavement-side soils in Algeria. It deals with the section of National Highway 3 (RN3), which crosses the wilaya of Batna. In the environment of sampling sites there is no industry or dangerous activity on the environment, the heavy metals addressed in this study are (Pb, Cu, Cr, Fe, Ni, Zn), their origin being road traffic. The objectives of this study were to: (1) Determine the concentrations of heavy metals in road dust; (2) Identify the sources of different heavy metals in soils and road dust; (3) Exploring the extent of heavy metal pollution in neighbouring soils. To this end, 33 samples were collected, including 03 road dust and 30 soil samples over different distances from 1m to 80m. The samples were analyzed by FRX. Results indicated that concentrations in road dust were higher than in soil. The distribution of heavy metal concentrations in dust is Fe>Pb>Zn>Cu>Cr>Ni, and the distribution in the ground is Fe>Pb>Cu>Zn>Cr>Ni in the direction of Biskra and in the opposite direction and decreases away from the road, while the distribution in the central solid ground is Fe> Cu>Cr>Pb>Zn>Ni. Climatic conditions such as wind, rainfall, temperature, humidity and the nature of the terrain were also significantly related to their enrichment in these roadside soils. The enrichment factor (EF) and the geo-accumulation index (Igeo) were calculated, as well as all elements with a (EF) that ranges from moderate to high to extremely contaminated, reflecting the high anthropogenic load of these metals in the study area and the results of the Igéo accumulation indices confirm the results obtained for the enrichment factor (EF). Doi: 10.28991/cej-2021-03091736 Full Text: PDF

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