New doctoral dissertation

June 14, 2024
VILNIUS TECH Library invites you to follow the published new dissertations. The dissertation „Development of alkali-activated materials using biomass fly ash, phosphogypsum, and recycled concrete aggregates“ ( „Šarminiu būdu aktyvuotų medžiagų kūrimas naudojant biomasės lakiuosius pelenus, fosfogipsą ir perdirbtus betono užpildus“) prepared by VILNIUS TECH, Chengjie Zhu. The dissertation was prepared in 2020–2024. Supervisor – Dr Ina Pundienė.

The dissertation will be defended at the public meeting of the Dissertation Defence Council of the Scientific Field of Materials Engineering in the SRA-I Hall of Vilnius Gediminas Technical University at 9 a. m. on 14 June 2024.

Cement production is responsible for 9–11% of total CO2 emissions worldwide, so it is essential to develop low-energy materials, avoiding using Port-land cement. Using waste materials in developing new cement-free binders, such as alkali-activated materials (AAMs), is a promising method for creating novel building materials. This study aims to develop a cement-free AAM binder based on high-carbon biomass fly ash (BFA), calcined phosphogypsum (CPG), and the low-alkalinity activator Na2CO3/Na2SiO3. The created AAM binder was used to develop a lightweight AAM concrete containing recycled concrete aggregate (RCA). The dissertation consists of an introduction, three chapters, general conclusions, recommendations, lists of references and the author’s publications on the dissertation topic, and a summary in Lithuanian. The first chapter reviews the state-of-the-art investigations on AAM, especially the application of BFA and CPG in AAM technologies. The literature states that BFA can be used as an aluminosilicate precursor with NaOH/Na2SiO3 in geopolymerisation technology. CPG participates as a calcium source, creating new minerals in the AAM and significantly enhancing its early strength. The second chapter describes the characteristics of the raw materials used, the mix design, and the sample preparation for each part of the research. It also describes the techniques and methods that were tested to fully evaluate the effect of each parameter on the rheological properties, physical-mechanical properties and reaction products of AAM samples based on BFA, CPG, and RCA. The third chapter presents the results and analysis of the research. It determines the effect of the Na2CO3/Na2SiO3 ratio and temperature on the properties and reaction products of BFA-based AAM. Also, it investigates the influence of the CPG content and Na2CO3/Na2SiO3 ratio on the properties and reaction products of BFA-CPG-based AAM. Furthermore, it reveals the effect of the RCA content on the physical-mechanical properties of AAM concretes based on BFA, CPG, and RCA. The lightweight AAM concrete can be applied to non-structural components with low strength requirements. Five scientific papers were published on the dissertation topic: three in scientific journals included in the Clarivate Analytics Web of Science database with an impact factor, and two in conference proceedings included in the Clarivate Analytics Web of Science and Scopus databases. Eight reports, including the dissertation results, were presented at national and international scientific conferences.

Doctoral dissertation readers can search via VILNIUS TECH Virtual Library.

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Student Memo: Where to park your car or bicycle, eat, and find your classrooms
Student Memo: Where to park your car or bicycle, eat, and find your classrooms
When starting your studies, it is not always clear during the first week where you can park your car or bicycle, which building your seminar will be in, or where you can eat or heat up your own food during breaks. To make settling into the academic year easier, we have prepared this memo. Student Car Parking: Students attending lectures at Saulėtekio al. 11 can park their cars in the lot located on Šatrijos Raganos Street. There is no barrier in this lot. How to find the lot: Driving from Saulėtekio al. – going up the hill past the roundabout and the university buildings. Or entering from Pragiedrulių, Mileišiškių sodų, or other streets onto Šatrijos Raganos Street – going down the hill before the roundabout and the university buildings. Students attending lectures on Plytinės Street can park in the lots located there. Students can enter the gated lot by tapping their activated student ID card at the terminal. Entrance to the lots is from Plytinės Street. Antanas Gustaitis Aviation Institute (AGAI) students, lecturers, and students or staff arriving at "Linkmenų fabrikas" can park in all lots. The barrier opens by tapping an activated student or staff ID card at the terminal. There are no dedicated parking lots for students attending lectures at the Old Town Campus (Trakų rūmai). Canteens and Cafes: Saulėtekis Campus: "Maisto imperija" (Building S2, 1st floor) – weighed food (you can build your own plate) – 1.70 € per 100 g, lunch of the day – 7.50 €, snacks, coffee, and other drinks. You can also heat up your own food here. Working hours: Monday–Thursday: 08:00–16:00; Friday: 08:00–15:00. "ARC BISTRO" (Building S3, 1st floor) – a menu consisting of a multi-course selection and daily lunch at a fixed price (up to 10 €), as well as snacks, coffee, and other drinks. Working hours: Monday–Friday: 11:00–15:00. Plytinė Campus (P2, 1st floor): "Confetti" – a menu consisting of a multi-course selection and daily lunch at a fixed price (up to 10 €), as well as snacks, coffee, and other drinks. You can also heat up your own food here. Working hours: Monday–Thursday: 09:00–16:00; Friday: 09:00–15:00. Old Town Campus (Senamiesčio rūmai): "Confetti" (Islandijos str. 3) – a menu consisting of a multi-course selection and daily lunch at a fixed price (up to 10 €), as well as snacks, coffee, and other drinks. Working hours: Monday–Friday: 07:45–15:00. Places where you can heat your own food in microwaves: When using microwaves, please maintain cleanliness, follow safety rules, and respect others: do not put in or heat items with shiny surfaces (e.g., cutlery, aluminum foil, etc.), do not slam the doors or other surfaces, wipe or clean the inside of the microwave or other surfaces (including the kitchenette) if needed, do not cut in line, and do not stop someone else's food from heating without permission, etc. Saulėtekis Campus: In the "Maisto imperija" canteen (Building S2, 1st floor), as well as in the Sustainability Centre (Building S5), and the 5th and 6th-floor kitchenettes in Building S6. Plytinė Campus: In the "Confetti" cafe (Building P2, 1st floor). Old Town Campus: In the Faculty of Architecture's 2nd and 3rd-floor kitchenettes (at the end of the corridor). AGAI: In the 2nd-floor kitchenette of the old building (near the Dean's office). It is planned that microwaves will also be available in the new building in the future. Linkmenų Campus: In the 2nd-floor kitchenette at "Linkmenų fabrikas". Library: Room 119, 1st floor. You can also make tea/coffee here. Places to leave your bicycle: Saulėtekis Campus: At special bike racks near the entrance to Building S2, and in the Central Building parking lot. Plytinė Campus: In the two designated bicycle shelters in the courtyard between buildings P1 and P2. Old Town Campus: At special bike racks near the entrances to each building. AGAI and Linkmenų Campus: At special bike racks near both departments. Library: At special bike racks near the entrance. Department/Building Abbreviations: Saulėtekis Campus (Saulėtekio al. 11, Vilnius): S1 Central Building (Administration, International Studies Centre, International Relations Office, etc.) S2 Classroom Building S3 Educational Building (Faculty of Civil Engineering, Faculty of Business Management) S4 Classroom Building (Faculty of Environmental Engineering, Sustainability Centre, Food Laboratory) S5 Educational Building (Faculty of Environmental Engineering, Sustainability Centre, Food Laboratory) S6 Laboratory Building (Faculty of Fundamental Sciences, Information Technology and Systems Centre, Academic Support Centre, etc.) S7 Laboratory Building Plytinė Campus (Plytinės str. 25, Vilnius): P1 or P Laboratory Building P2 Educational Building (Faculty of Electronics, Faculty of Mechanics, Faculty of Transport Engineering) P3 Educational Building Linkmenų Campus (Linkmenų str. 28, Vilnius): L1 Building (Institute of Building Materials) L2 Building (Road Research Institute) L3 Building L4 Building L5 Educational Building (Linkmenų fabrikas) L6 Educational Building (Antanas Gustaitis Aviation Institute) Old Town Campus (Trakų str. 1, Vilnius): T1 or T Educational Building (Faculty of Architecture) T2 Educational Building (Faculty of Creative Industries) T3 Educational Building T4 Educational Building T5 Educational Building Old abbreviations that might still appear in some contacts: SNR – Senamiesčio rūmai (Old Town Campus) SRK-I – Saulėtekio rūmų pirmas korpusas (Saulėtekis Campus First Building) SRK-II – Saulėtekio rūmų antras korpusas (Saulėtekis Campus Second Building) SRL – Saulėtekio rūmų laboratorinis korpusas (Saulėtekis Campus Laboratory Building) SRL-II – Saulėtekio rūmų antras laboratorinis korpusas (Saulėtekis Campus Second Laboratory Building) MAC – Saulėtekio centriniai rūmai (Saulėtekis Central Building) AGAI TLK – Antano Gustaičio Aviacijos instituto Treniruoklių ir laboratorijų korpusas (Antanas Gustaitis Aviation Institute Simulator and Laboratory Building). Other Addresses: Kyviškės Airfield: Lakūnų str. 7D, Kyviškės Sports and Art Centre: Saulėtekio al. 28, Vilnius Library: Saulėtekio al. 14, Vilnius Lithuanian Maritime Academy: I. Kanto str. 7, Klaipėda. Thematic Reading Rooms in Faculties: Architecture and Creative Sciences Reading Room (Trakų str. 1, T1, 1.15, Vilnius) Technology and Management Sciences Reading Room (Saulėtekio al. 11, S1, C03, Vilnius) Mechanics, Electronics, and Transport Sciences Reading Room (Plytinės str. 25, P2, 179, Vilnius) Maritime Sciences Reading Room (I. Kanto str. 7, Klaipėda)
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