Loading...
2 results
Search Results
Now showing 1 - 2 of 2
- Synthesis and Characterisation of CO2 Activated Binders and Concretes using Industrial Wastes for Precast Buildings ApplicationsPublication . Humbert, Pedro Silva; Gomes, João Paulo de CastroThe scope of this thesis is the synthesis and characterization of binders produced with steel slag from the National Steel Industry, in Maia and Seixal, Portugal, and activated by accelerated carbonation curing. This doctorate thesis presents an extensive study over this technology beginning with the state-of-the-art discussion, evidencing the most relevant studies about the topic, as well as systematically identifying the research aspects which must be further investigated and consequently approached on this thesis. The steel slag from the National Steel Industry has its properties characterized by a different analysis which determined its density and fineness. An elemental characterization was possible through a scanning electron microscopy analysis, an X-ray diffraction analysis was done in order to characterize the steel slag mineralogical phases. The sample preparation process is discussed in detail highlighting the phases of drying, milling, grain size separation, mixing, and compaction. Performing these steps ensures compliance and reliability of results, plus influences the final product properties allowing optimal conditions parameterization and final product improvements by manipulating each process phase parameters. A study related to the use of additives on the steel slag hardening process with carbon dioxide (CO2) curing is also evidenced and compared with relevant research in correlated areas. A wide study about the accelerated carbonation curing conditions was performed which evidenced the controlled parameters and the respective influence on the final results by manipulating each of them. Oven temperature, system total pressure, curing duration, and humidity were the investigated parameters and had their respective effects systematized. In addition, with the CO2 curing, an analysis of the effect of complementary curing methods on the binder’s compressive strength development was carried on. The carbonated steel slag binders were subjected to complementary curing for the specific duration under four different conditions: in an oven, moisture room, plastic bag and under water. The complementary curing effects were exposed and discussed. The microstructure characterization of steel slag-based binder activated by CO2 was performed by scanning electron microscopy analysis, X-ray diffraction analysis and thermogravimetric analysis, accomplishing the identification of the formed products on the steel slag carbonation. The study defined optimal activation conditions and applied the same conditions to the Portland cement for comparison purposes. Moreover, Portland cement had its characterization performed.
- Alkali-activation of tungsten mining waste mud blended with waste glass: reactivity, performance and innovative applicationsPublication . Gomes, João Castro; Magrinho, Manuel; Sedira, Naim; Beghoura, Imed; Humbert, Pedro; Manso, Maria; Fernandes, Ana; Silva, RafaelMines and quarries waste accounts for about 29% of the total generated waste from industrial processes and households in Europe. The reuse of mud tailings as precursor materials for alkali-activated binders and applications are very promising from a technical and environmental point of view. The aim of the present study was to develop added-value solutions to reutilize tungsten mine mud tailings in alkali activated materials. Some potential uses of these new materials obtained from alkali-activation of tungsten mud waste and other precursor materials, as well incorporating expanded granulated cork, such us a high energy efficient panel for a vegetated surface and a foamed lightweight brick wall, are presented.