Journal of Civil Engineering Beyond Limits (CEBEL)

Mostafa Shaker Mahdi Saad Issa Sarsam

Asphalt concrete usually practices cracking and distress during its service life. However, recycling process as well as crack healing phenomena can enhance the physical properties and extend the pavement service life. This investigation is concerned with monitoring the microcrack healing of recycled asphalt concrete through its influence on deformation measurement under three testing techniques, repeated (compressive, tensile and shear stresses). Reclaimed asphalt concrete mixture was recycled with [carbon black-asphalt] and [Styrene Butadiene Rubber (SBR)-asphalt] rejuvenators. Specimens have been tested with the aid of the pneumatic repeated load system (PRLS). The repeated loading of the three testing techniques was terminated after 1000 load repetitions, and the specimens could heal by external heating at 60°C for 120 minutes. Specimens were returned to the (PRLS) and subjected to another run of repeated stresses application after healing. It was concluded that the deformation increases after recycling process while it declines after microcrack healing regardless of the testing technique adopted. The deformation declines by (31.8, 5.8 and 19)%, (43 ,49 and 24 )% and (44 ,10 and 13 )% under three level of repeated compressive stresses of (0.068, 0.138, and 0.206) MPa at (40 °C) after healing cycle for reclaimed and recycled mixture with (carbon black-asphalt) and (SBR-asphalt) respectively when compared with permanent deformation before the healing cycle. The permanent deformation under repeated punching shear and indirect tensile stresses declines after microcrack healing by (32, 26 and 25.7) % and (73, 78.7 and 78.2) % for reclaimed, recycled with (carbon black-asphalt) and recycled with (SBR-asphalt) mixtures respectively.

https://doi.org/10.36937/cebel.2020.004.001

Azwan Morni Murvin Manap

In this study, the adsorption and the filtration processes were coupled by a zeolite nanoparticle impregnated polysulfone (PSf) membrane which was used to remove the lead and the nickel cations from synthetically prepared solutions. The results obtained from X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive X-ray (EDX) analysis indicated that the synthesized zeolite nanoparticles, using the conventional hydrothermal method, produced a pure NaX with ultrafine and uniform particles. The performance of the hybrid membrane was determined under dynamic conditions. The results also revealed that the sorption capacity, as well as the water hydraulic permeability of the membranes, could both be improved by simply tuning the membrane fabricating conditions such as evaporation period of the casting film and NaX loading. The maximum sorption capacity of the hybrid membrane for the lead and nickel ions was measured as 682 and 122 mg/g respectively at the end of 60 min of filtration, under 1 bar of transmembrane pressure. The coupling process suggested that membrane architecture could be efficiently used for treating metal solutions with low concentrations and transmembrane pressures.

https://doi.org/10.36937/cebel.2020.004.002

Mahyar MAALI Mahmut KILIÇ Abdulkadir Cüneyt AYDIN Bariş BAYRAK Haluk Gorkem ALCAN

Reinforced concrete (RC) structures have their own weight, earthquake, wind, dead loads, live loads, creep, etc. throughout their service life. They are exposed to internal and external load effects. In order to meet the horizontal forces such as earthquake and wind from these loads affecting the structure, shear wall structures with high lateral rigidity are needed. Therefore, shear walls are one of the most important structural elements that can resist earthquake forces due to their high lateral rigidity and load bearing capacities. Most of the buildings today are designed according to the old regulations. Therefore, the shear wall was sized and reinforced according to these old regulations. However, to date, standards have been renewed in certain periods. Despite this, shear walls designed according to the old regulations continue to resist seismic forces. In this study, the design and behavioral differences of the reinforced concrete shear walls between the Turkish Regulation that came into force in 2019, and the old regulation were compared. In addition, RC shear walls were evaluated according to ACI-318-19 and EuroCode-2 regulations.

https://doi.org/10.36937/cebel.2020.004.003

Yusuf Demirel Ömer POLAT

The present study reports on an experimental investigation of the effect of a blast inside a reinforced concrete room on the behavior of the reinforced concrete structure. To this end, a blasting experiment was carried out inside a concrete room, with pressure values obtained using a piezoelectric pressure sensor. After the experiment, measurements and observations were made within the reinforced concrete room, and sketches were made of the cracks that formed on the various concrete wall types, and on the floor and wall coverings. The gathered data, measurements and observations were then used in a theoretical study. The obtained pressure values were used to analyze the effects of the blast on the room components, making use of ABAQUS software, with both dynamic and static analyses conducted separately. The results of the theoretical study of the behavior of the building components, which was carried out in accordance with international regulations and standards, were then compared with the experimental values.

https://doi.org/10.36937/cebel.2020.004.004

Farah Q. Al-Naje Alaa H. Abed Abbas Al-Taie

The engineering problems of problematic soils are mainly related to their mechanical, physical, and mineralogical properties. Extensive efforts have been directed to mitigate damages that may happen for structures constructed on, or in these soils' types. Both conventional materials (e.g. cement, lime, etc.), chemical and produced materials were blended, mixed, or added to soils to improve their geotechnical properties. In the last years, different additives from the wastes of industrial processes have been adopted in engineering researches to improve soils. This paper reviews different industrial wastes materials (e.g., fly ash, blast slag, rice husk ash) as soil stabilizers, where the use of them has economic and engineering benefits. The effect of these materials on physical properties, compaction characteristics, compressive strength, and bearing ratio of soils have been presented, studied, and discussed. The contents of these materials are widely varied from reference to reference and reach a maximum value of 50%. These materials cause reduction in Atterberg limits and swelling potential to different degrees. For some soils, MDD and OMC increase with the addition of these materials, and verse versa. Almost, these materials cause an improvement in soils' strength and CBR. However, some wastes reveal more efficiently to improve the soil.

https://doi.org/10.36937/cebel.2020.004.005