Investigations of the characteristics of elasticity and creep of concrete in the Andizhan reservoir dam

Conclusions

• 1. The rate of increase of the modulus of elasticity of concrete at an early age directly in the dam depends on the ambient temperature associated with exothermic heating of the cement in the concrete, season of concreting, etc. In the case of heating of the concrete to plus 30–32° an increase of the modulus of elasticity ends mainly by 14 days, and in the case of a moderate temperature of heating of the concrete to plus 18–20°, which is characteristic for the fall-winter concreting period, an increase of E of concrete can continue for up to 180 days.

• 2. The values of the modulus of elasticity of concrete placed at various times of the year equalize with increase of age of the concrete. The final values of E of concrete at an age of 1 year and more directly in the structure do not depend either on the concreting season or on the temperature of heating of the concrete at early period of hardening. The average final value of the modulus of elasticity of concrete M250 of the dam is 3.94×10⁴ with a coefficient of variation ν<3% and range of experimental values W=28%.

• 3. The moduli of elasticity of concrete at a late age obtained on large laboratory specimens and directly in the structure are close in value.

• 4. Creep of concrete of massive structures depends on the ambient temperature and, consequently, on the season of placing the concrete in the structure.

• 5. Under the same temperature conditions creep of concrete directly in the structure and of large laboratory specimens is close in value.