Study on setting time and compressive strength performance of ordinary portland cement (OPC) paste containing sodium chloride
The presence of impurities in concrete system can possess a damaging effect to the structural integrity of concrete material. Alkali silica reaction, scaling, and corrosion are among the deleterious effect caused by the ingression of internal or external substance to the concrete system. Sodium c...
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| Format: | Undergraduates Project Papers |
| Language: | English |
| Published: |
2014
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| Subjects: | |
| Online Access: | http://umpir.ump.edu.my/id/eprint/10110/1/RAHIMAH%20BINTI%20EMBONG%20%23.PDF http://umpir.ump.edu.my/id/eprint/10110/ |
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| Summary: | The presence of impurities in concrete system can possess a damaging effect to
the structural integrity of concrete material. Alkali silica reaction, scaling, and corrosion
are among the deleterious effect caused by the ingression of internal or external
substance to the concrete system. Sodium chloride or salt is one of the external agents
involved in the process; hence its excessive amount in concrete system is strictly
prohibited. Nevertheless, concrete containing
salt
water is generally known for the
higher early-strength, yet lower ultimate strength than plain concrete. Meanwhile, study
on the detail mechanism in early age properties are scarcely available, particularly at
low salt concentration. Therefore this research was conducted to provide better
understanding in the effect of salt water to the hardening mechanism of Portland cement
paste and to obtain the optimum salt inclusion that contributes to the enhancement of
concrete properties. Analysis on the performance of this reagent was conducted via
setting time, compressive strength, and porosity test. Based on the setting time analysis,
the inclusion of sodium chloride can extend the initial setting time of cement paste
longer than control specimen. Obstruction on the formation of calcium silicate hydrate
gel by sodium and chloride ion was one of the possible causes to this phenomenon.
Acceleration on the compressive strength development by sodium chloride was also
detected. It appears that sodium chloride was able to de-flocculate the coagulated
cement particles and reduced the viscosities of cement slurries; hence resulted in faster
early hydration process. Based on the results of this research, it can be concluded that
sodium chloride inclusion is beneficial to the workability and compressive strength
performance of cement paste binder at certain concentration. Improvement of
compressive strength was achieved via faster dissolution and hydration of cement
particle due to dispersant characteristic presented by sodium chloride. |
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