Journal of Engineering and Innovation

The effectiveness of construction workers in the reinforced concrete residential construction project: a case study of column concrete pouring activity

2026-06-15T22:03:42+07:00

This research investigates the labor effectiveness of construction workers in single-story reinforced concrete residential projects, with a primary focus on column concrete pouring activities. Initially, Work Breakdown Structure (WBS) analysis and questionnaires were employed to identify critical activities causing project delays. Field data regarding worker behavior were then collected using the Five-Minute Rating method across ten column-related sub-activities. This data was analyzed to assess labor effectiveness and establish improvement guidelines by applying Crew Balance Charts for workload reallocation. By strategically reassigning support responsibilities to designated workers, the proposed approach facilitates continuous and uninterrupted concrete pouring. The results indicated that the concrete pouring activity demonstrated the lowest average effectiveness at 76%. Ultimately, these workload reallocation measures aim to significantly reduce idle time and maximize overall construction productivity. After the process improvement and workload reallocation, the average effectiveness of the crew significantly increased to 92%, demonstrating a substantial reduction in idle time.

A study on the utilization of municipal solid waste incineration ash as an additional raw material in interlocking blocks

2026-05-19T11:31:24+07:00

This study aims to explore the utilization of municipal solid waste incineration ash, which has been increasingly generated and poses storage challenges, as a partial replacement for aggregates in the production of interlocking blocks. The research focuses on evaluating the physical and mechanical properties, including compressive strength, unit weight, and water absorption. Specimens were prepared with cement-to-lateritic soil ratios of 1:6, 1:7, and 1:8, incorporating ash at replacement levels of 10%, 20%, 30%, 40%, and 50% by weight. All samples were cured for 7, 14, and 28 days and tested according to the Thai Community Product Standard (TCPS 602/2547). The results revealed that increasing ash content reduced the unit weight of the blocks due to its lower density, while water absorption tended to increase as a result of higher internal porosity. Notably, at a cement-to-soil ratio of 1:6 with 10% ash and 28-day curing, the compressive strength reached 70.2 kg/cm² and water absorption was 104 kg/m³, meeting the requirements for load-bearing interlocking blocks. These findings indicate that controlled incorporation of incineration ash can produce blocks that comply with national standards while reducing the use of conventional materials. This approach not only lowers production costs and enhances the value of waste materials but also provides a sustainable solution for mitigating environmental impacts associated with ash disposal in communities.

Carbon reduction in construction with reused structural members from building demolition – a case study: school building construction from apartment structural members

2026-07-17T15:28:28+07:00

Currently, building demolition primarily relies on destructive methods, generating a substantial amount of construction and demolition waste that is typically landfilled. This practice not only wastes valuable resources but also causes environmental pollution. Therefore, efficient waste management through systematic material sorting and planned deconstruction is crucial. Reusing dismantled components in new construction projects can significantly reduce both resource consumption and environmental burdens. This research aims to investigate the mitigation of environmental impacts in building construction by reusing structural components from a deconstructed building. A case study was conducted on the deconstruction of a 4-story residential building (apartment) to construct a 2-story school building. The quantities of the existing structural members were evaluated using BIM-based quantity takeoff, and the load-bearing capacities of the original columns and beams were analyzed. These components were then modified and substituted into the new school building's structure based on appropriate lengths and structural strength requirements. The results revealed that 55.71% of the structural components from the residential building could be successfully reused in the new school building. Based on a Life Cycle Assessment (LCA) from the material production phase to construction completion, carbon emissions were reduced by 39.35% compared to conventional construction methods. In terms of project management, the construction duration was shortened by 36.36%, and direct construction costs decreased by 23.07% compared to conventional construction methods. However, this study excluded the costs associated with the demolition and transportation of the reused structural members, which are variables that should be considered in future research.

Ozone treatment of asphalt exhaust

2026-07-16T12:34:08+07:00

Asphalt is a semi-solid to liquid hydrocarbon material with a brownish-black color, widely used in road construction and maintenance. When heated to high temperatures during paving operations, asphalt generates volatile organic compound (VOC) fumes containing polycyclic aromatic hydrocarbons (PAHs), posing significant occupational health hazards. This study investigated the physical characteristics of asphalt cement AC 60/70, measured total volatile organic compound (TVOC) fume concentrations generated at heating temperatures of 100°C, 200°C, and 300°C for asphalt masses of 5, 10, and 15 g, and evaluated the efficiency of ozone (O₃) treatment for fume removal using batch and continuous flow processes at 5 ppm ozone concentration. The average density of asphalt was 1.046 g/cm³. At 100°C and 200°C, equilibrium TVOC concentrations remained generally below the occupational exposure limit (OEL) of 0.5 mg/m³ established by NIOSH and ACGIH. At 300°C, concentrations reached 10 mg/m³, exceeding the OEL 20-fold, with an average fume release rate in the range of 1.192×10^-3 - 4.966×10^-3mg/min. Ozone treatment achieved 100% fume removal efficiency: the batch process required 10–20 minutes and the continuous flow process required 16–30 minutes, depending on asphalt mass. These results demonstrate that ozone treatment is a highly effective approach for controlling asphalt exhaust emissions in occupational environments.

Production improvement for reducing the number of dented cans in a pet food manufacturing plant: a case study

2026-08-14T16:55:22+07:00

This research aimed to improve the production process of a can unloading machine during the can conveying stage in order to reduce defective products, particularly dented cans, in a case study of a pet food manufacturing plant. The problem was initially investigated using a check sheet to collect preliminary data over a two-week period in June 2025. The study focused on the can conveying process, which involved a total of nine can unloading machines. The data on the occurrence of dented cans from all machines were then prioritized using a Pareto chart. The results indicated that Unloader No. 3 had the highest frequency of dented cans, accounting for 499 defective cans out of a total of 1,471 dented cans, or 29%. Therefore, the researchers conducted a root cause analysis based on the 4M framework (Man, Machine, Material, and Method) using a fishbone diagram. The PDCA (Plan-Do-Check-Act) cycle was then applied to identify and implement improvement measures to reduce the occurrence of dented cans on Unloader No. 3. The results showed that the number of dented cans produced by Unloader No. 3 decreased from an average of 2,158 cans per month to 1,270 cans per month. This represented an average reduction of 41.14% in dented cans per month. In addition, the average reduction in damage costs was 8,880 Thai baht per machine per month, equivalent to approximately 106,656 Thai baht per machine per year. The improvement effectively reduced both the number of defective products and the associated average monthly damage costs of Unloader No. 3, which was selected as the improvement case. The proposed improvement approach can also be applied to other can unloading machines or production equipment to further enhance production efficiency.

Development of octave-based reliability analysis software for civil engineering using Monte Carlo simulation

2026-09-02T12:02:45+07:00

This paper presents the development of ORA-CE (Octave-Based Reliability Analysis for Civil Engineering), a software tool designed to evaluate the reliability of civil engineering problems using Monte Carlo Simulation (MCS) based on defined performance functions. The software operates through an integrated workflow between Microsoft Excel and GNU Octave. Microsoft Excel serves as the front-end interface for user inputs—including user-defined complex performance functions, random variables, probability distribution types, and total simulation sample sizes—which are subsequently transmitted to GNU Octave, an open-source, license-free platform, for computational reliability analysis. To validate ORA-CE, benchmark case studies from the published literature were evaluated. The validation process initially involved a convergence study of the failure probability to determine an optimal sample size. A quantitative statistical error analysis was then conducted to confirm that the selected sample size yields stable and reliable statistical estimates. Subsequently, the reliability results obtained using the determined sample size were compared against reference values. The calculated failure probabilities yielded relative errors ranging from 0.88% to 2.03%, demonstrating excellent numerical agreement with the literature. Furthermore, these comparative findings confirm the validity of the core script architecture and the random variable generation utilizing built-in statistical functions in GNU Octave. Overall, ORA-CE proves to be an efficient, convenient, and cost-effective alternative tool for structural safety assessment in civil engineering without software licensing burdens.

Comparative study on fire resistance performance of composite slabs with different cross-sections using finite element analysis

2026-08-14T15:07:43+07:00

The objective of this research is to investigate the behavior of composite slabs under fire conditions using finite element analysis. Firstly, the numerical analysis employed a 3D non-linear coupled thermal-structural ANSYS model. Thermal validation against reference test results yielded a mean relative error below 3.5% and a maximum temperature discrepancy within 12.7 °C, verifying the model's accuracy. This study investigated the effects of cross-sectional shape on the temperature distribution, load-bearing capacity, and thermal insulation of composite slabs exposed to fire. Two profile types, trapezoidal and re-entrant, were analyzed using the ISO 834 standard fire curve. The results revealed that the re-entrant profile exhibited superior thermal resistance, resulting in lower internal temperatures after 50 minutes of fire exposure. Consequently, the residual load-bearing capacity ratios for the trapezoidal and re-entrant profiles were 33.48% and 36.59%, respectively. Under the ISO 834 thermal insulation criterion, the trapezoidal and re-entrant profiles achieved insulation fire ratings of 70 and 100 minutes, respectively. These findings indicate that cross-sectional geometry significantly influences the fire resistance of composite slabs. Ultimately, selecting an appropriate profile can substantially enhance structural safety under fire conditions.