Thesis published in Dept. of C.E. http://103.99.128.19:8080/xmlui/handle/123456789/12 2026-11-14T12:14:32Z 2026-11-14T12:14:32Z BARUA, BAKUL ID:, 21MCE031P http://103.99.128.19:8080/xmlui/handle/123456789/609 2026-11-10T04:04:15Z 2025-07-30T00:00:00Z

PERFORMANCE OF NANO SILICA GEL PRODUCED FROM RISE HUSK ASH (RHA) IN CEMENTITIOUS MEDIA BARUA, BAKUL; ID:, 21MCE031P This study investigates the use of Nano-Silica Gel (NSG) derived from Rice Husk Ash (RHA) as a sustainable alternative in cement-based composites. RHA, rich in amorphous silica, is an eco-friendly source for NSG production, which can enhance cement performance and reduce environmental impact. Experimental tests were conducted on pastes and mortars by replacing cement with NSG dosages of 1%, 2%, 3%, and 5% to evaluate flowability, density, setting time, compressive strength, flexural strength, shrinkage, soundness, electrical resistivity, and pozzolanic activity. Scanning Electron Microscopy (SEM) and X-ray Diffraction (XRD) were also used to analyze microstructural changes at 7, 28, and 90 days. Results showed that 1% NSG significantly improved compressive strength (53.9 MPa) and flexural strength (6.94 MPa) at 90 days, compared to the control mix. This improvement is due to the highly reactive nature of NSG, which accelerates the formation of calcium-silicate-hydrate (C-S-H) gel, enhancing the matrix and pore structure. However, higher NSG dosages (≥3%) decreased strength and stability due to increased water demand and particle agglomeration. Pozzolanic activity was moderate at 1–2% NSG but declined at 5%. The Frattini test confirmed moderate pozzolanic activity at lower dosages; however, the benefits diminished at the highest replacement level (5%). Lower NSG levels improved electrical resistivity, while higher dosages increased porosity. In conclusion, NSG derived from RHA could be a viable and effective supplementary cementitious material when used at optimal replacement levels. Specifically, a 1% NSG substitution shows the best balance of enhanced strength and other relevant properties. The use of RHA-derived NSG also contributes to sustainability goals by reducing the demand for cement, an energy intensive material. This work offers valuable insights into advancing sustainable practices in the construction industry by promoting waste utilization and reducing the carbon footprint associated with cement production. A Master of Engineering (M.Engg.) thesis submitted to the Department of Civil Engineering (CE), Chittagong University of Engineering and Technology (CUET).

2025-07-30T00:00:00Z Mayin, Md. Hafiz-Al http://103.99.128.19:8080/xmlui/handle/123456789/607 2026-11-10T03:59:19Z 2025-07-22T00:00:00Z

SUITABILITY OF MODIFIED BINDERS FOR SUSTAINABLE FLEXIBLE PAVEMENT CONSTRUCTION IN CONTEXT OF BANGLADESH Mayin, Md. Hafiz-Al 60/70 bitumen is used as the main binder in pavement construction of Bangladesh which experiences numerous types of defects require frequent maintenance and are extremely vulnerable to traffic loading, moisture damage and temperature changes. Hence, an effort has been made to enhance the bitumen quality by adding modifiers with the neat bitumen. And also, bituminous concrete mixes have been evaluated for some performance parameters to justify the bitumen quality. On the other hand, vehicles are increasing approximately 0.5 million per year in Bangladesh with the increase of life standard, country development, economic zones, population and road network which produce a significant amount (150,000 tons) of non-biodegradable waste tires. It may be advantageous for the environment and the economy by using this waste material as a bitumen modifier, producing Crumb Rubber Modified Bitumen (CRMB). Polymer Modified Bitumen (PMB) is used in many countries over the world due to its enhanced properties, so it has also been considered to verify the suitability over neat binder and CRMB. The research includes laboratory investigation of binders (60/70, PMB & CRMB) properties and found CRMB has more enhanced. Marshall mix design approach has been used to determine the Marshall properties and Optimum Bitumen Content (OBC). The OBC’s of bituminous mixes prepared by neat 60/70 bitumen, PMB, and CRMB were found to be 5.05%, 5.10% and 5.30% respectively. The retained stability of 60/70 bitumen, PMB, and CRMB mixtures were found to be 79.0%, 92.6% and 95.0% respectively. Based on Indirect Tensile Strength (IDT) test, the Tensile Strength Ratio (TSR) values for the respective mixtures were found to be 84.0%, 94.4% and 93.2%. Again, based on moisture induced damage test, the TSR values were found to be 83.1%, 90.1% and 93.0% for the respective bituminous mixes. The modified bitumen showed higher softening point, higher elastic recovery, lower temperature susceptibility and lower stripping value. Moreover, higher resistance to moisture induced damage and retained stability were observed for the modified bituminous mixes. Finally, it can be concluded that, the performance of modified binders are better than that of neat 60/70 bitumen as they are less susceptible to temperature and moisture, causing less maintenance and rehabilitation costs over the pavement's lifespan. Since the CRMB performed best out of the two modified bitumen, it can be considered as a sustainable alternative for durable and effective road development in Bangladesh. A Master of Engineering (M.Engg) Thesis in Civil Engineering (CE) Department at Chittagong University of Engineering and Technology (CUET).

2025-07-22T00:00:00Z Halder, Shovon http://103.99.128.19:8080/xmlui/handle/123456789/606 2026-11-10T03:58:30Z 2025-07-22T00:00:00Z

PERFORMANCE OF PERVIOUS ASPHALT PAVEMENT USING WASTE POLYETHYLENE MODIFIED BINDER Halder, Shovon The escalating demand for sustainable and resilient pavement solutions, coupled with growing environmental concerns regarding polyethylene waste, has catalyzed the exploration of innovative materials within pavement engineering. This study undertook an experimental evaluation of pervious asphalt pavement utilizing waste polyethylene-modified bitumen to enhance mechanical strength and functional durability, while promoting sustainable waste repurposing. In Bangladesh, where the rainy season lasts nearly seven to eight months, conventional pavements face persistent drainage challenges and reduced lifespan. In this study, 60/70 penetration grade bitumen was modified by incorporating 3%, 4%, 5%, and 6% waste polyethylene by weight. Binder tests— including penetration, softening point, ductility, viscosity, temperature susceptibility, and others—revealed that 4% polyethylene addition produced the most favorable results. The modified binder exhibited enhanced stiffness and lower susceptibility to temperature changes, with penetration values ranging from 11 at 5°C to 49 at 35°C, compared to 6 to 152 for unmodified bitumen. The optimum binder content (OBC) was determined to be within the range of 5.25 5.4%, based on Cantabro abrasion and draindown test results. The mix satisfied the Cantabro loss threshold of 15% and the maximum allowable draindown limit of 0.3%, as per MS-2. The air void content was also verified to be within the range of 18–22%, ensuring adequate permeability. Performance tests showed that polyethylene-modified mixes outperformed conventional mixes. Dry Marshall stability increased from 1.86 kN to 4.70 kN, and retained stability improved from 71.5% for the neat binder to 90.4% for the v modified mix, exceeding the minimum requirement of 75%. The Tensile Strength Ratio (TSR) also improved from 85% to 97%, indicating higher resistance to moisture damage. The coefficient of permeability increased from 3 mm/s in conventional mixes to 4.2 mm/s in modified mixes, confirming improved infiltration potential. These findings confirm that incorporating waste polyethylene enhances the structural and functional performance of pervious asphalt pavement, while also addressing environmental waste concerns. The proposed mix shows promise for low-volume roads and parking lots, particularly in high-rainfall regions, and offers a basis for future field applications and study. A Master of Science (M.Sc) Thesis in Civil Engineering (CE) Department at Chittagong University of Engineering and Technology (CUET).

2025-07-22T00:00:00Z Masum, A. K. M. http://103.99.128.19:8080/xmlui/handle/123456789/605 2026-11-10T03:57:26Z 2025-10-26T00:00:00Z

PERFORMANCE OF FERROCEMENT ANGLE TO RETROFIT THE PARTIALLY DAMAGED RC COLUMN Masum, A. K. M. Reinforced concrete (RC) columns are the most crucial building component in concrete buildings, resisting both gravity and lateral loads. Therefore, their effective retrofitting technique is a burning topic in the scientific community. This research investigates the performance of prefabricated ferrocement angles (PFAs) as a retrofitting solution for damaged RC columns. A total of 18 scaled-down square columns of three different concrete strengths of 36.40 MPa, 34.20 MPa and 31.40 MPa were experimentally investigated. The strength of the ferrocement used to make the PFAs was 39 MPa. Each concrete strength group consists of 6 columns: 1 control, 1 control pre-cracked, 2 retrofitted with single-layer wire mesh PFAs and 2 retrofitted with double-layer wire mesh PFAs. The complete retrofitting procedures involved the external application of PFAs at the column corners with bonding agents, joining the PFAs with each other by sewing wire meshes and filling the voids between PFAs with high-strength mortar. The specimens were tested under displacement-controlled axial loading and performance in regard to ultimate load capacity, stiffness, energy absorption, ductility and failure patterns were evaluated. The application of PFAs significantly increased the axial load capacity of the pre- cracked RC columns. Increasing the layer of wire mesh also increased the gain of axial load capacity by almost 50%. This increase was found to be more for RC columns of the higher concrete strength group, indicating the dependence of the axial load capacity increase after PFA jacketing on the actual concrete strength of the RC columns. PFA jacketing also helped to retain the stiffness of the pre- cracked samples while allowing greater lateral and axial deformation. Jacketing the pre-cracked columns with PFAs increased their energy absorption capacity by more than 100%. The proposed jacketing method of RC columns with PFAs viii also improved their ductility via the confinement effect, ensuring higher plastic deformation and preventing brittle failure. A Master of Engineering (M.Engg) Thesis in Computer Engineering(CE) Department at Chittagong University of Engineering and Technology (CUET).

2025-10-26T00:00:00Z