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Recent Submissions

Predicting Concrete Compressive Strength Using Aggregate Properties and Concrete Equivalent Mortar Tool Data A Machine Learning Approach
(Department of Civil and Environmental Engineering(MPE), Islamic University of Technology(IUT), Board Bazar, Gazipur-1704, Bangladesh, 2025-10-25) Mahbub, Nur-A-Piyas; Iqbal, Nafis; Fayej, M. Jubayer
With the goal to offer a productive, non-destructive alternative for typical, resource- intensive compressive strength (CS) tests, this thesis examines the potential uses of ma- chine learning (ML) techniques. This study aims to establish accurate predictive models for concrete quality assessment by incorporating sustainable materials, particularly used concrete aggregate, black stone, and brick chips. A dataset of 180 samples, divided us- ing an 80/20 ratio, was used to train and test several machine learning algorithms, such as Linear, KNN, and XGBoost.Two distinct approaches of prediction were developed. The first method used six features based on coarse aggregate physical properties (like absorption and angularity number) and the Concrete Equivalent Mortar (CEM) tool. With a R2 score of 0.6867 and an RMSE of 3.7280 MPa, the KNN Regression model proved to be the most reliable predictor on the test set in the present scenario. The second approach used 15 features, including component contents and engineered features ( such as load, age, and water-to-cement ratio), to predict CS directly from the full mix design parameters. With the Linear Regression model obtaining a superior R2 score of 0.9500 and an RMSE of 1.500 MPa, this method achieved significantly greater accuracy. The main reason for the substantial disparity in model performance—between the R2 values of 0.6867 and 0.9500— is the variation in input complexity; Compared to the physical properties approach, which used six features, the mix design approach had fifteen features, an increased number of influential variables which more accurately captured the multitude of relationships governing concrete strength. This study encourages the sustainable and cost-effective evaluation of concrete performance by successfully confirming the use of feature engineering with machine learning and detailed mix design parameters to achieve exceptional forecasting reliability.
Mechanical and Durability Properties of High Strength Mortar with Construction Waste and Recycled Wastewater
(Department of Civil and Environmental Engineering(MPE), Islamic University of Technology(IUT), Board Bazar, Gazipur-1704, Bangladesh, 2025-10-25) Mujtaba, Nakib; Twinkle, Nusrat Kamal; Hasan, Shafinur
This study explores the combined use of two industrial by-products, Concrete Waste (CW) and Recycled Water (RW) as sustainable alternatives in High-Strength Mortar (HSM). The goal of this study is to reduce the environmental impact of cement production and sand extraction in the construction industry. We addressed the research gap by testing seven mixtures with 100% RW and varying amounts of CW as a replacement for cement or sand. We evaluated mechanical and durability properties using standardized tests for compressive strength (ASTM C 109), sorptivity (ASTM C1585), and drying shrinkage (ASTM C596). The results showed that using 100% RW is a practical option, with the control mix achieving 91.3 MPa. The replacement strategies were important, such as- substituting cement with CW led to a decrease in compressive strength (down to 60.3 MPa) and reduced durability. On the other hand, replacing sand with CW produced excellent results. The 40SRW mix, which replaced 40% of the sand, maintained compressive strength at 91.7 MPa and sorptivity at 0.0036 /√s, similar to the control mix. It also shows better dimensional stability, reducing drying shrinkage by 15.6%. The study concludes that the 40SRW formulation is an ideal sustainable mixture. It also supports a circular economy approach by delivering high mechanical performance and durability while maintaining structural integrity.
Reuse of Broken Tile as Coarse and Fine Aggregate in Concrete
(Department of Civil and Environmental Engineering(MPE), Islamic University of Technology(IUT), Board Bazar, Gazipur-1704, Bangladesh, 2025-10-25) Salam, Tahsin; Ahmed, Labib Zawad; Shafayat, Farhan
Effectiveness of Large SODIS Reactor Under Tropical Climate Condition with H2O2
(Department of Civil and Environmental Engineering(MPE), Islamic University of Technology(IUT), Board Bazar, Gazipur-1704, Bangladesh, 2025-10-25) Sharna, Mobashira Hossain; Bushra, Takia
Access to safe drinking water remains a critical public health concern in developing countries, where conventional water treatment technologies are often expensive or unavailable in rural areas. Solar Water Disinfection (SODIS) offers a simple, affordable, and sustainable method that uses solar radiation to inactivate waterborne pathogens. However, its efficiency can decline under cloudy conditions, high turbidity, or when sunlight exposure is insufficient. To enhance the effectiveness of the process, this study investigated the performance of an H₂O₂-assisted SODIS system using a large-scale 10 L transparent PET reactor under natural tropical sunlight in Gazipur, Bangladesh. Experiments were conducted during both the summer and monsoon seasons to capture variations in solar irradiance and temperature. Two types of test waters were prepared: tap water (TW-1) and a mixed lake water sample (TW-2) containing 5% surface water to simulate natural contamination. Escherichia coli (ATCC 25922) was introduced as an indicator organism, and the effects of pH (5.5-12) and H₂O₂ concentration (5-15 mg/L) were analyzed. Samples were collected hourly over 6 hours of exposure and examined using the m-TEC membrane filtration method to determine bacterial log reduction. The results showed that the combined solar-hydrogen peroxide process achieved faster and more consistent disinfection compared to conventional SODIS. Under summer conditions, with average solar irradiance exceeding 800 W/m² and water temperatures above 45°C, complete E. coli inactivation (≥5-log reduction) was achieved within 4-5 hours at an optimized 10 mg/L H₂O₂ and pH 7.5. During the monsoon season, lower irradiance required a longer exposure of 6-7 hours to reach similar reductions. Higher H₂O₂ doses (15 mg/L) reduced efficiency slightly due to radical self-scavenging, while extreme pH values (5.5 and 12) negatively affected inactivation. The presence of organic matter in TW-2 also slowed the process, indicating that water quality influences radical availability and light transmission. Kinetic modeling revealed that bacterial inactivation followed a Double Weibull pattern, characterized by an initial rapid kill phase followed by a slower tailing phase. The inactivation rate constant (k) was higher in summer (1.56 h⁻¹) than in monsoon (0.92 h⁻¹), confirming seasonal dependence. Statistical analysis (R² > 0.95) demonstrated strong correlations between solar intensity, temperature, and disinfection efficiency. Moreover, regrowth analysis showed that the residual 1-2 mg/L H₂O₂ vi remaining after treatment effectively prevented microbial recovery during 24-hour storage, addressing a major limitation of traditional SODIS. This study demonstrates that integrating a low concentration of hydrogen peroxide into SODIS significantly improves its disinfection efficiency, reduces treatment time, and prevents bacterial regrowth under tropical conditions. The optimized configuration: 10 mg/L H₂O₂ at pH 7.5 with 6 hours of sunlight exposure, proved to be both effective and practical. These findings suggest that photo-assisted and H2O2 modified SODIS can serve as a sustainable, low-cost solution for providing safe drinking water in resource-limited tropical regions.
Transformation of Locally Available Soil into Sub-Base Material Using K-31 Stabilizer
(Department of Civil and Environmental Engineering(MPE), Islamic University of Technology(IUT), Board Bazar, Gazipur-1704, Bangladesh, 2025-10-25) Rashedi, S.M Rifat; Newaz, Shakib; Hoque, Md. Janibul
The increasing demand for durable and sustainable road infrastructure has intensified the need to enhance the engineering properties of weak, locally available soils in Bangladesh. Many construction areas, particularly those containing red and clayey soils, fail to meet the minimum sub-base strength and bearing requirements specified by the Roads and Highways Department (RHD). Transporting high quality aggregates from remote locations substantially raises construction costs and environmental impact. To address this challenge, the present research investigates the potential of transforming locally available soil into a suitable sub-base material through chemical stabilization using the K-31 polymer. In this study, red soil samples collected from the Gazipur region were treated with varying K-31:water ratios to determine the optimum mix that yields the best mechanical performance. Laboratory experiments were conducted to evaluate Unconfined Compressive Strength (UCS), California Bearing Ratio (CBR), and compaction characteristics of both untreated and treated soils. The results revealed a significant improvement in load-bearing capacity and density with increasing K-31 concentration up to an optimal range, beyond which strength gains stabilized. Treated specimens exhibited enhanced resistance to moisture intrusion and reduced plasticity, confirming the polymer’s effectiveness in improving soil cohesion and reducing permeability. The findings demonstrate that K-31 stabilization provides a rapid, cost-efficient, and environmentally friendly alternative to conventional cement- or lime-based stabilization techniques. Its performance in laboratory conditions suggests strong potential for field application in flexible pavement sub-bases within Bangladesh. The study concludes that the K-31 polymer stabilizer can effectively transform locally available weak soils into reliable sub-base materials, contributing to sustainable infrastructure development while minimizing the dependency on imported aggregates and high-carbon binders.