Awoyera, P. O. and Covenant University, Theses (2018) Mechanical and microstructural characterization of ceramic-laterized concrete composite. PhD thesis, Covenant University, Ota, Nigeria.
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Abstract
Ceramics is one of the solid wastes generated from construction and demolition sites, or industries that can constitute nuisance to the environment. Hence, reusing this kind of waste could be of immense benefit not only to the construction industry but also to the environment. This research focused on the mechanical and microstructural characterization of ceramic-laterized composite. The mechanical properties of mortar and concrete elements produced using cementitious composite, comprising of blended ceramic-cement as binders, ceramic aggregate, laterite and conventional aggregates, were determined after the samples have been cured by immersion in water. Non-destructive tests were performed on the hardened mortars, using X-ray CT scan and Ultrasonic Pulse Velocity (UPV) techniques. Also, dry bulk density, water absorption due to capillarity, compressive and flexural strength of mortars were determined. Mechanical properties of concrete such as compressive, split-tensile and flexural strength of concrete cubes, cylinders and prisms were determined. Next, predictive models for determining the compressive and split-tensile strength of ceramic-laterized concrete were developed using the Artificial Neural Network (ANN) technique. The results of compressive and split-tensile strengths obtained from this study and those of related studies were utilized for the model development. Finally, micro scale analysis was performed on mortar fragments from selected mixes, which revealed the hydration mechanism and pore structure of the concrete, as they relate to the strength properties. The concrete specimens were characterized using more advanced analysis techniques, comprising of Scanning Electron Microscopy, in secondary and backscattered electron modes, X-ray Diffractometer, mercury intrusion porosimetry (MIP), and thermogravimetric analysis (TGA). From the results, a mortar sample which was composed of 10% powdered ceramics as cement replacement, and 100% fine ceramics as sand replacement developed better strength characteristics than the reference mortar. The micro scale analysis showed that the best mortar mix developed larger peaks of Ettringite, Portlandite and Calcite minerals than the reference mortar. This could be the cause of its high strength. While for concrete, the reference mix yielded higher mechanical properties than the concrete containing secondary aggregates. However, a laterized concrete mix comprising both 90% of ceramic fine and 10% of laterite as the fine aggregate provided the optimal strength out of all the modified mixes, and this was the case whether the coarse aggregate was 100% granite or 100% coarse ceramics. Although, the strength reduction was about 9% when compared with the reference case, this reduction in strength is acceptable, and does not compromise the use of these alternative aggregates in structural concrete. Thus, this has shown that ceramic aggregate could be adequately used to supplement or totally replace natural aggregate in concrete while laterite could be sparingly used as replacement for river sand.
| Item Type: | Thesis (PhD) |
|---|---|
| Uncontrolled Keywords: | Ceramic wastes; Green concrete; Hydration mechanism; Laterized concrete; Microstructure; Porosity |
| Subjects: | T Technology > T Technology (General) T Technology > TA Engineering (General). Civil engineering (General) |
| Divisions: | Faculty of Engineering, Science and Mathematics > School of Civil Engineering and the Environment |
| Depositing User: | Dr. Paul Awoyera |
| Date Deposited: | 30 Oct 2018 10:11 |
| Last Modified: | 30 Oct 2018 10:58 |
| URI: | http://eprints.covenantuniversity.edu.ng/id/eprint/12045 |
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