Method of investigating the elastoplastic characteristics of concrete in the mass of a hydraulic structure

Conclusions

• 1. The most widely used laboratory method for investigating massive concrete in a structure is conditional and only approximately reflects the properties of the concrete.

• 2. A study of the elastoplastic characteristics of concrete of massive structures in full scale is recommended to be done directly in the structure by testing samples isolated during concreting of the blocks.

• 3. In the case of a small height of the concreting blocks (1.5 m and lower) and aggregate size of the concrete of 100–150 mm it is recommended to place prismatic samples horizontally in the blocks.

• 4. The horizontal arrangement of the sample in the block, unlike the traditional vertical, permits conducting tests at any age of the concrete beginning with the earliest and at any height of the block encountered in practice, including the minimum, 0.5 m; it provides free access to the instruments during assembly, and the probability of their damage during filling of the forms with the concrete mix is minimized; constancy of the temperature field over the entire area of the sample is also preserved.

• 5. Gluing three layers of pergamyn (artificial paper parchment) on a graphite lubricant on the inside walls of the sample forms provides free deformation of the samples longitudinally and transversely from the axial compressive load and protects them from external forces in the mass.

• 6. The examined method for studying concrete in massive structures in comparison with other methods, including laboratory testing of samples prepared without screening out the largest aggregate and testing of bored cores, yields more reliable data, is less labor-consuming, is more economical, and permits investigating concrete at any time during the entire life of the structure.

• 7. The successful investigations of the elastoplastic characteristics of the concrete in the Toktogul dam by testing the isolated horizontal samples directly in the mass would recommend this method for wide use during construction of other hydrodevelopments.