ABSTRACT
This paper explores the composition of concrete for energy piles. The target concrete is designed to serve not only as a structural foundation, but also heat exchanger as the pile-soil interaction occurs. The studies of the possible replacements (20%, 30% and 40%) of granite gravel in concrete compositions for energy piles have found that the optimum content of the reinforcement steel cuttings is 30%. With a 40% content, the compressive strength of concrete tends to decrease due to the stress concentration in the mortar phase. The findings indicate that by spreading themselves evenly in concrete mixture without contacting one another, the pieces of waste reinforcement steel increase the density of concrete, its compressive strength, thermal conductivity, and water absorption, as was shown by the sample tests. The statistical analysis has shown that there is a linear relationship between the content of waste reinforcement steel and the density and thermal conductivity of concrete, which makes waste reinforcement steel an expedient ingredient in energy piles manufacture.
