Chloride permeability of mortar containing metakaolin | |
| Author | Amrit Siri-isranant |
| Call Number | AIT Thesis no.ST-06-02 |
| Subject(s) | Mortars Kaolin Concrete construction |
| Note | A thesis submitted in partial fulfillment of the requirements for the degree of Master of Engineering, School of Engineering and Technology |
| Publisher | Asian Institute of Technology |
| Series Statement | Thesis ; no. ST-06-02 |
| Abstract | Chloride permeability is the most influencing factor that affects the durability of concrete. The main objective of this study is to investigate the influence of metakaolin having different percentage cement replacement and various degrees of fineness on chloride permeability of mortars. Rapid chloride permeability test (RCPT), water absorption test, and compressive strength test were performed on mortars containing metakaolin. The relationships between all test results were experimentally investigated. In this experiment, metakaolin was used as a supplementary cementing material to replace an ordinary Portland cement type I by the percentage of 20%, 30%, and 40% by weight of cement. The other variable was fineness of metakaolin. The degree of fineness of metakaolin was varied to be 13000 cm2/g, 1 1000 cm` /g, and 8000 cm `/g by varying the duration of grinding. Water to binder ratio was kept constant at 0.5. The consistencies of mortar for all mixes were also kept constant. The flow of fresh mortar was controlled to be in the range of 1 10±5% by varying the dosage of superplasticizer. Test results showed that metakaolin can be satisfactorily used as a cement replacement material in order to reduce the chloride permeability and hence increases the durability of mortar. Chloride permeability and water absorption of mortar containing higher metakaolin content are both decreased as the metakaolin content increases. Compressive strength of mortar is also decreased as the metakaolin replacement level increases. Mortar containing higher replacement level of metakaolin needs more superplasticizer in order to maintain the same consistency as the mortar without metakaolin. Chloride permeability and water absorption are decreased when the fineness of metakaolin is increased. For the range of parameters used in this study, fineness of metakaolin has little or no effect on compressive strength. Mortar containing metakaolin having higher degree of fineness needs more superplasticizer to produce the same consistency. Chloride permeability and water absorption of mortar containing metakaolin can be directly related. When the metakaolin content is increased, charge passed based on chloride permeability is decreased, water absorption is also decreased. When the fineness of metakaolin was higher, both charge passed and water absorption becomes lower. Strength reduction and low workability are important factors to be considered especially when using metakaolin replacement in large proportion. It is recommended that only 20% metakaolin replacement is sufficient to enhance the chloride penetration resistance. When using 30% or 40% replacement level, the compressive strength is reduced and higher dosage of superplasticizer is needed to maintain consistency and this results in higher cost. As for the fineness of metakaolin, the metakaolin having specific surface area 8000 cm2/g is sufficient to improve the durability. The results of the finer metakaolin are not significant to the durability of mortar |
| Year | 2006 |
| Corresponding Series Added Entry | Asian Institute of Technology. Thesis ; no. ST-06-02 |
| Type | Thesis |
| School | School of Engineering and Technology |
| Department | Department of Civil and Infrastucture Engineering (DCIE) |
| Academic Program/FoS | Structural Engineering (STE) /Former Name = Structural Engineering and Construction (ST) |
| Chairperson(s) | Pichai Nimityongskul; |
| Examination Committee(s) | Kato, Yoshitaka;Pennung Warnitchai; |
| Scholarship Donor(s) | Royal Thai Government Fellowship; |
| Degree | Thesis (M.Eng.) - Asian Institute of Technology, 2006 |