Journal of Civil Engineering Beyond Limits (CEBEL)

Barış BAYRAK Abdulkadir Cüneyt Aydın

The accurate prediction of labor productivity is critical for achieving efficiency, cost control, and timely completion in construction projects. However, conventional forecasting methods often fail to capture the nonlinear and dynamic interactions among human, environmental, and managerial factors. This study presents an artificial intelligence (AI)-based framework for predicting labor productivity in construction processes using machine learning and deep learning techniques. Three models—Artificial Neural Network (ANN), Random Forest (RF), and Support Vector Machine (SVM)—were developed and trained using an integrated dataset containing variables such as labor hours, equipment availability, worker experience, material supply, temperature, and supervisory efficiency. The models were evaluated using the coefficient of determination (R²), root mean square error (RMSE), and mean absolute error (MAE). The ANN model achieved the highest predictive accuracy (R² = 0.94), followed by RF (R² = 0.91) and SVM (R² = 0.88). Residual and feature importance analyses revealed that labor hours (23.6%), equipment availability (18.4%), and worker experience (14.7%) were the most influential parameters affecting productivity. The ANN exhibited a symmetric and unbiased error distribution, confirming its robustness and generalization capability across diverse project conditions. The proposed AI-based framework offers a data-driven decision-support system that enables project managers to proactively monitor performance, allocate resources efficiently, and minimize schedule deviations.

https://doi.org/10.36937/cebel.2025.11075

Mehmet Emin ARZUTUĞ

Purification of wastewater is crucial for human health and for preventing groundwater contamination. Removing copper ions from wastewater produced by industrial facilities using electrodeposition is an effective method for eliminating heavy metals. This study aimed to investigate the effects of the inter-electrode distance and the pH of the electrolyte on the k in electrodeposition, which simulates the electrocoagulation removal of copper from artificial wastewater. The experimental study on copper removal was conducted in a jacketed PVC reactor, stirred using a four-bladed Rushton turbine. The removal of copper, an electrochemical mass transfer process with diffusion-controlled, was performed under limiting current conditions. The electrodeposition technique used in this study combines elements of ELDCT and NST. The experimental results indicate that k values increased with decreasing the anode-cathode distance and the decrease in pH of the electrolyte. Because the change in the pH affected the concentration of Cu2+ ions, k values were also changed. Thus, the copper removal rate from the solution on the cathode was decreased. For this process, the Sherwood (Sh) correlation grew depending on the parameters of inter-elecrode distance and pH. The following equation gave this correlation: Sh=460〖*(R⁄d)〗^(-0.51) 〖*pH〗^(-0.63). According to experimental results, k decreased from 4.65.10-6 m/s to 2.70.10-6 m/s linearly as inter-electrode distance increased from 4.3cm to 8cm. Besides, k decreased exponentially from 5.6.10-6 m/s to 4.10-6 m/s as pH changed from 0.53 to 1.42. ).

https://doi.org/10.36937/cebel.2025.11079

Serdal Ünal Mehmet CANBAZ

This study investigates the use of waste glass powder from Turkish glass manufacturing as a precursor for sustainable building materials. Cement-free geopolymer elements were produced using only waste glass powder, water, and sodium hydroxide. We measured unit weight, ultrasonic pulse velocity, and compressive, flexural, and splitting-tensile strengths across NaOH dosages; 4% NaOH yielded the best overall performance. The geopolymer samples were compared with traditional building materials (aerated concrete and brick) for density and mechanical strength, demonstrating their potential as a sustainable alternative. In particular, the compressive and tensile strength results show that such materials have the potential to be used as lightweight and durable building elements in the construction industry. The approach also reduces environmental burden and supports the circular economy by valorizing glass waste. The use of geopolymeric materials is seen as a solution to reduce carbon emissions from cement production and support the achievement of global climate goals. Therefore, completely cement-free structural elements, termed 'Glassmer,' were developed. The term “Glassmer,” coined by combining “Glass” and “Polymer,” is used in this study to denote the geopolymeric binder produced entirely from waste glass powder activated with sodium hydroxide. Findings highlight environmental and economic benefits and outline directions for future work.

https://doi.org/10.36937/cebel.2025.11076

Saad Issa Sarsam

Additives can modify and enhance the important properties of asphalt binder. An attempt was made in this work to use four types of additives (sulfur, fumed silica, Phosphogypsum and fly ash) to alter the properties of asphalt binder. The modified asphalt cement binders were tested for static and dynamic contact angles determination and SFE evaluation using the Sessile drop (SD) and the Wilhelmy plate (WP) techniques. It was noticed that the SFE increased by (33.4, 51.5, 98.1, 114.4, and 77.3) % for control, (sulfur, fly ash, fumed silica, and phosogypsum) modified mixtures respectively when WP method was used as compared to that of the SD method. The use of the additives increased the base component element of static contact angle (SCA) by (5.15, 24.1, 38.7, 44.3) % for sulfur, fly ash, silica fumes, and Phospho-gypsum additives respectively while the Lifshitz-van der Walls (LW)component element increased by (13.4, 12.2, and 24) % for fly ash, silica fumes, and Phospho-gypsum additives respectively when compared with that of the control binder, However, implementation of sulfur exhibit decline in the LW component element of SCA of 2.1 %. Implementation of sulfur shows significant increase in the dynamic contact angle (DCA)of (67, 42, and 67.7) % and for LW, base, and acid components respectively, while implementation of phosogypsum showed an increase in the DCA components of (18.3, and 10.8) % for LW, and acid components respectively. Sulfur additive exhibits the highest SFE, and it is recommended for modification of the asphalt binder.

https://doi.org/10.36937/cebel.2025.11068

Saad Issa Sarsam

Oil refineries in Iraq supply various types of asphalt cement. The environmental conditions across the country exhibit a significant temperature range of -15℃ to over 65℃ between winter and summer as well as an hourly variation in temperature between day and night of ± 20℃. The potential properties of asphalt concrete due to such harsh environment which accelerate the ageing process of the binder can vary. The influence of short- and long-term ageing on the physical properties of asphalt concrete prepared with asphalt binders of the same penetration grade obtained from Dourah, Erbil, and Nasiriyah refineries was assessed. The variation in the physical properties of asphalt concrete samples were tested for temperature susceptibility and volumetric properties such as bulk density, voids content %, voids filled with binder Vfb %, and voids in mineral aggregates VMA %. Asphalt concrete mixtures were prepared with optimum binder requirements and subjected to short and long-term ageing processes respectively. It was concluded that implementation of asphalt binder of the same penetration grade but from varied asphalt sources shows different behavior after practicing the ageing process. Erbil binder exhibits the lowest susceptibility to temperature variation of 35.42 kPa/°C among other asphalt binders. After the ageing process, the voids content increases by (38.8, 52.9 and 60) % for Nasiriyah, Erbil and Dourah binders respectively. The mathematical models obtained fit into the experimental observation with high accuracy. Hence, the models are practical to be used to predict the changes in volumetric properties of asphalt concrete throughout the ageing process.

https://doi.org/10.36937/cebel.2025.11046