AI SearchBleeding and abrasion resistance of mortars containing different pozzolans
Call Number: AIT Thesis no.ST-06-01 Material type:
SeriesSeries: Asian Institute of Technology. Thesis ; no. ST-06-01Publication details: Pathum Thani, Thailand : Asian Institute of Technology, 2006Description: 74 leaves : illSubject(s): Online resources: Dissertation note: Thesis (M.Eng.) - Asian Institute of Technology, 2006 Summary: Bleeding is a form of segregation in which some of the water in the mix tends to rise to the surface of freshly placed concrete. Excessive bleeding increases the water to cement ratio near the top surface. Therefore, a weak top layer with poor durability may result. The purpose of this study is to investigate the influence of different types of pozzolans on the bleeding characteristics and abrasion resistance of mortars. Four types of pozzolan were investigated namely fly ash, silica fume, rice husk ash, and metakaolin and the replacement percentages ranged from 5% - 40% depending on the type of pozzolan. The bleeding of mortar was determined based on ASTM C 243-85 Standard Test Method for Bleeding of Cement Pastes and Mortars. The parametric study was designed based on fixed value of flow and fixed water to binder ratio. Different percentages of pozzolan and pozzolan combination depended on the type of pozzolan were experimentally investigated in order to minimize bleeding. In addition, the abrasion resistance and compressive strength at different ages of mortar, which containing different types and percentages of pozzolan were also determined. Test results could be described from 2 main parameters namely controlled water to binder ratio and fixed value of flow. Regarding the control of water to binder ratio, the bleeding of fresh mortar increased as the replacement percentage of fly ash was increased. However, the bleeding of mortar could be significantly reduced by using the silica fume, rice husk ash, and metakaolin. When the value of flow was fixed, it was found that water content was reduced to maintain the flow value of fresh mortar while the replacement percentage of fly ash was increased. This resulted in a reduction of bleeding in the mix. Regarding the bleeding of mortar containing silica fume or metakaolin, the water requirement increased when higher percentage replacement was used. In turn, the bleeding of mortar containing rice husk ash tended to gradually increase as the water to binder ratio was increased. Finally, it could be concluded that the use of combination of 30% fly ash and 3% metakaolin as cement replacement with decreasing water requirement was the appropriate solution to reduce bleeding and increase the abrasion resistance of mortar
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A thesis submitted in partial fulfillment of the requirements for the degree of Master of Engineering, School of Engineering and Technology
Thesis (M.Eng.) - Asian Institute of Technology, 2006
Bleeding is a form of segregation in which some of the water in the mix tends to rise to the surface of freshly placed concrete. Excessive bleeding increases the water to cement ratio near the top surface. Therefore, a weak top layer with poor durability may result. The purpose of this study is to investigate the influence of different types of pozzolans on the bleeding characteristics and abrasion resistance of mortars. Four types of pozzolan were investigated namely fly ash, silica fume, rice husk ash, and metakaolin and the replacement percentages ranged from 5% - 40% depending on the type of pozzolan. The bleeding of mortar was determined based on ASTM C 243-85 Standard Test Method for Bleeding of Cement Pastes and Mortars. The parametric study was designed based on fixed value of flow and fixed water to binder ratio. Different percentages of pozzolan and pozzolan combination depended on the type of pozzolan were experimentally investigated in order to minimize bleeding. In addition, the abrasion resistance and compressive strength at different ages of mortar, which containing different types and percentages of pozzolan were also determined. Test results could be described from 2 main parameters namely controlled water to binder ratio and fixed value of flow. Regarding the control of water to binder ratio, the bleeding of fresh mortar increased as the replacement percentage of fly ash was increased. However, the bleeding of mortar could be significantly reduced by using the silica fume, rice husk ash, and metakaolin. When the value of flow was fixed, it was found that water content was reduced to maintain the flow value of fresh mortar while the replacement percentage of fly ash was increased. This resulted in a reduction of bleeding in the mix. Regarding the bleeding of mortar containing silica fume or metakaolin, the water requirement increased when higher percentage replacement was used. In turn, the bleeding of mortar containing rice husk ash tended to gradually increase as the water to binder ratio was increased. Finally, it could be concluded that the use of combination of 30% fly ash and 3% metakaolin as cement replacement with decreasing water requirement was the appropriate solution to reduce bleeding and increase the abrasion resistance of mortar
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