A study on the effect of casting and curing temperature on the mechanical properties of concrete.
Conventional winter concreting practice in Canada recommends concrete to be mixed and placed at 10°C or above and be cured for seven days (not necessarily consecutive) at which the air temperature is above 10°C. However, construction of offshore Arctic structures will usually take place at temperatu...
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| Format: | Thesis |
| Language: | unknown |
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Université d'Ottawa / University of Ottawa
1984
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| Online Access: | https://dx.doi.org/10.20381/ruor-8378 http://www.ruor.uottawa.ca/handle/10393/10621 |
| Summary: | Conventional winter concreting practice in Canada recommends concrete to be mixed and placed at 10°C or above and be cured for seven days (not necessarily consecutive) at which the air temperature is above 10°C. However, construction of offshore Arctic structures will usually take place at temperatures close to that of the sea at approximately 0 to 4°C; and hence information on the influence of temperature during mixing, placing and curing on the development of concrete strength is essential. Previous research has shown conflicting results on the effect of casting and curing temperature. Since the economic benefits of being able to place and cure concrete at low temperature without any strength penalty are significant, this study was undertaken to examine the effect of casting and curing temperature on the mechanical properties of concrete. Standard concrete cylinders made of type 10 Portland cement were cured extensively at 0°C, 16°C and 43°C after holding the specimens at various casting temperatures for 3 to 12 hours to separate the effect of casting temperature and curing temperature. Concrete prisms were also cast and cured at 0°C, 16°C and 45°C to determine dynamic modus of elasticity. The tests an compressive strength, indirect tensile strength, static and dynamic modulus of elasticity were carried out at the ages of 3, 7, 14, 26 and 90 days. In general, the compressive strength increased with increasing time and decreasing water-cement ratio. The lower the water-cement ratio, the faster the concrete gained its strength. The effect of temperature on the strength development was found to be depended upon the water-cement ratio of the concrete. The study showed that casting and curing at 0°C or 45°C would not damage the concrete strength but conversely increased the strength if the water-cement ratio was kept below 0.35. Concrete cast and cured several hours at 0°C or 45°C and subsequently cured at 16°C received no damage but benefits to its strength providing water-cement ratio was as low as 0.45. However, extreme casting or curing temperature should be discouraged for water-cement ratio above 0.55. Tensile strength, static and dynamic modulus of elasticity increased with increasing compressive strength but at a different rates depending on the casting and curing temperature. Tensile strength, static and dynamic modulus of elasticity were related to the power of 0.60, 0.65 and 0.31 of the cylinder strength, respectively. |
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