The intensification of efforts to create urban living space makes it necessary to build upward rather than outward. As a result, up to 415,000 new housing units are built annually in South Korea, of which 160,000 are in the primary metropolitan area of Seoul (Mordor Intelligence, 2021). The resulting residential areas are often characterized by closely spaced high-rise buildings. This requires precise planning as well as meticulous control of all relevant parameters during construction. In particular, the structural integrity of buildings during rapid construction phases is essential to ensure safe and efficient building processes. Monitoring the quality of fresh concrete plays a central role in ensuring reliable quality assurance even under tight construction schedules. In South Korea, special geographical and resource-specific requirements must also be taken into account. On the densely populated, hilly peninsula, sand has become a scarce resource and is now also extracted from the sea and subsequently washed or mixed with soils and other ground materials. As in Central Europe, the share of recycled materials used in fresh concrete production is also increasing here. Reliable control of the water content in concrete mixes is therefore essential to achieve consistently high quality and enables full documentation.