Aerial work with helicopters in the construction of cableways and their impact on the concrete mixture design

Abstract

Slovakia is a rugged country, a significant part of which consists of mountain areas. Construction activities in these localities should consider specific natural conditions, while taking into account economic issues. In these cases, the efficient way of construction is the use of aerial work, so the execution of constructions using helicopters. However, compared to conventional technologies, helicopters are limited in their work by several factors, which are mainly related to their movement in a three-dimensional environment (atmosphere). The aim of this article is to show how the choice of fresh concrete mixture is related to the work of helicopters, to design a suitable mixture for the currently valid Slovak requirements and to test it in laboratory conditions. The selection of the mixture is narrowly specialized for the construction of reinforced concrete footings of cableways, which are typically realized in mountain areas. The results showed that by using a suitable superplasticizer based on polycarboxylates, it is possible to ensure the required workability of fresh concrete within 180 minutes. However, the condition must always be met that the onset of setting of the used cement does not occur earlier than 180 minutes. Longer workability time can be achieved by adding a retarding additive.