Journal of Civil Engineering Beyond Limits (CEBEL)

Saad Issa Sarsam

Recycling of aged AC mixture is a sustainable process used to prolong the useful life of the AC pavement. In the present work, Reclaimed Asphalt Pavement (RAP) was obtained from the in-service field pavement and recycled with a mixture of binder and carbon black (CB). Laboratory specimens of Marshall size were prepared from both RAP and recycled mixtures. Part of AC specimens were subjected to (MD)process, then practiced the DITS at (25 and 40) °C environment at constant stress level of 138 kPa in the pneumatic repeated load system (PRLS) with constant loading frequency of 60 cycles per minute. The dynamic loading sequence for each cycle is 0.1 seconds of load duration and 0.9 seconds of rest period. The permanent microstrain (PM) and FN were recorded before and after the MD. At 25° C environment, the MD process exhibited a decline of FN by (80, and 72.5) % for RAP and recycled mixtures respectively. However, in the 40° C environment, the MD process exhibited a decline of FN by (75, and 33) % for RAP and recycled mixtures respectively. Before the MD process, the increment of testing temperature from (25 to 40) °C exhibited decline in FN of AC mixtures by (40, and 62.5) % for RAP and recycled AC mixtures respectively. The recycling index after practicing MD is higher than before MD for FN and PM. Recycling index increases at higher testing temperature of 40 °C as compared to that at 25 °C for PM regardless of testing condition.

https://doi.org/10.36937/cebel.2026.11135

Md. Harun Ar Rashid Kaniz Fatema Abhishek Sharma Md. Azaharul Islam Raju

Safe drinking water is essential for good health. But overgrowing population, geological formation, climatic change, soil erosion, pesticide & fertilizer application, and urbanization are responsible for the pollution of water and variation of the quality parameters of water. This study deals with the suitability of groundwater quality in four upazilas in the Dinajpur district, Bangladesh. In Dinajpur the major source of drinking water is provided by hand-pumping shallow tube wells. 32 water samples from those upazilas were collected (eight from each upazila) for laboratory testing. The important physicochemical parameters, such as temperature, pH, electrical conductivity, total dissolved solids, calcium, magnesium, hardness, bicarbonate, alkalinity, nitrate, and bacteriological parameters, such as total bacteria count, fecal coliform, and Escherichia coli were assessed. Then the testing data were in comparison with the World Health Organization (WHO) & Bangladesh Standards (BDS). The comparison showed that the water was suitable for daily use for the people according to standards. Physiochemical parameters were within the standard level except pH which was low in Dinajpur Sadar, hardness exceeded the limit according to WHO in Biral and Dinajpur sadar upazilas. In Biral, the concentration of magnesium exceeded the standard limits, and nitrate values were exceeded in all upazilas according to BDS. All the samples are free from microbial contamination. In addition, continuous monitoring of the chemical parameters of water is needed for its use in Dinajpur district, Bangladesh.

https://doi.org/10.36937/cebel.2026.11124

Alireza Mirzaei Khosrow Bargi

Although extensive research has been conducted on the seismic and progressive collapse behavior of steel moment-resisting frames (MRFs), limited attention has been given to the influence of different seismic design provisions on the resistance of these systems against progressive collapse. This study investigates the progressive collapse resistance of high-ductility MRFs designed according to the seismic requirements of ASCE 7-22 and NBCC 2020. Three-, six-, and nine-story archetype frames were designed using ETABS in accordance with AISC 360-22/AISC 341-22 and CSA S16-19 requirements. The designed structures were subsequently modeled in OpenSees using concentrated plasticity elements and validated nonlinear modeling procedures. Nonlinear pushover analyses were performed to evaluate key seismic performance parameters, including overstrength, ductility, stiffness, and plastic hinge development. In addition, nonlinear pushdown analyses were conducted under interior- and exterior-column removal scenarios following the GSA guidelines to assess structural resistance against progressive collapse. The results indicate that frames designed according to NBCC 2020 generally exhibit larger member sizes, higher steel consumption, greater initial stiffness, and higher lateral and vertical load-carrying capacities than their ASCE 7-22 counterparts. Consequently, NBCC-designed frames develop larger overstrength factors and substantially greater progressive collapse resistance. In contrast, ASCE-designed frames demonstrate higher ductility and deformation capacity under seismic loading. Plastic hinge distributions indicate that the intended strong-column weak-beam mechanism was achieved in most archetypes. Overall, the results demonstrate that column location plays a critical role in progressive collapse behavior, with interior-column removal leading to substantially higher collapse resistance and more stable post-yield response compared with exterior-column removal.

https://doi.org/10.36937/cebel.2026.11154

Abdulkadir Cüneyt Aydın

The presented critical review the seismic performance of self-compacting hybrid fiber reinforced concrete (SCC-HFRC) shear walls, addressing the structural vulnerabilities and reinforcement congestion common in traditional reinforced concrete designs. Utilizing a combination of macro-steel and micro-polypropylene fibers, the study investigates how multi-scale crack bridging mechanisms enhance the shear strength, energy dissipation, and drift capacity of structural walls. The methodology integrates large-scale cyclic testing with advanced analytical modeling based on the Modified Compression Field Theory and Concrete Damaged Plasticity. Findings demonstrate that SCC-HFRC walls maintain stable hysteretic behavior at drift levels up to 3.0%, even when traditional boundary zone confinement is reduced by as much as 75%. The hybrid fiber synergy transforms brittle failure modes, such as web crushing, into ductile responses characterized by dense networks of fine hairline cracks. By providing an independent matrix shear contribution of approximately 4.5 to 6.0 times the square root of the compressive strength, HFRC offers a robust alternative to dense steel detailing. The paper concludes that transitioning toward performance-based displacement design can significantly improve the constructability and resilience of high-rise urban infrastructure in seismic regions.

https://doi.org/10.36937/cebel.2026.11170

Marjuka Mehjabin Arnob Pritom Basak Nirmal Chandra Roy Md. Rashedul Haque

The increasing demand for sustainable construction materials has led to the selection of supplementary cementitious materials (SCMs) to minimize the environmental burden of Portland cement manufacturing. This paper experimentally investigates the effect of varied volume of fly ash replacement on some fresh, mechanical and physical properties of M25-grade concrete and also develops machine learning-based models to predict performance. In this study, examining the effect of different fly ash replacement levels (0%-50%) on hardened concrete properties, six distinct concrete mixes were designed with constant water-to-cementitious material ratio (0.48) and 144 cylindrical specimens were casted from all mixtures to determine compressive strength, splitting tensile strength, workability and unit weight at age of 7, 14 and 28 days respectively. Although increasing fly ash content improved workability, high replacement levels reduced compressive and splitting tensile strength because of cement dilution and the relatively slow early-age pozzolanic reaction of Class F fly ash. Containing approximately 20–30% replacement levels, the best all-round performance with moderate compressive and tensile strength alongside cement mass reduction. It also employs the Random Forest and Extreme Gradient Boosting (XGBoost) regression models to predict compressive strength of a mixture from its variables. The prediction performances of the XGBoost model were more accurately represented (R² = 0.951; RMSE=1.128 MPa; MAE=0.966 MPa). The findings demonstrate the potential of ensemble-learning models to support preliminary fly ash concrete mix evaluation, although validation using larger independent datasets is necessary.

https://doi.org/10.36937/cebel.2026.11172