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CONCRETE TECHNOLOGY80 CPI %u2013 Concrete Plant International %u2013 5 | 2025 www.cpi-worldwide.comThe 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.In South Korea, the determination of the water content in fresh concrete has been mandated using one of four identified measurement methods and is particularly challenging due to the differing resource origins described above. Methods based on measuring electrical capacitance in the fresh concrete in particular are highly susceptible to variations in conductivity.The measurement methods, which could hardly be more diverse, include the microwave drying method, a digitalized air content tester, a technique based on capacitance measurement technology, and a TDR method. The latter is robust German measurement technology that has been on the market for almost 10 years. Developed by a small company in Baden-W%u00fcrttemberg, the device enables particularly rapid determination of the water content in fresh concrete using a dielectric technique known as Time Domain Reflectometry.The basis of the legally mandated %u201cKorean Standard%u201d is a 2022 publication that examined the measurement accuracy of the various methods (Park & Han, 2022). In this study, water content tests were carried out on a range of fresh concrete mixes with different binder compositions, aiming at investigating measurement errors and verifying the reliability of the different water content testing methods. For the concrete samples tested, the water content measurement methods for fresh concrete achieved a high success rate with 97% of results falling within the permissible range of %u00b110 kg/m%u00b3.The 51 tests conducted showed that the quality of the concrete is directly influenced by the constituent materials used. The sample quantity obtained is crucial for measurement accuracy: the larger the sample that can be analyzed with the testing method, the lower the risk of errors during sampling. Accordingly, the lowest relative error was recorded for the TDR penetration measurement method (Sono WZ), which also requires the shortest measurement time (only two minutes) among the approved methods. The drying method requires 15 minutes, while the capacitance measurement and the digitized air content meter each take 8 minutes per measurement and are based on much smaller sample sizes (Park & Han, 2022).This also explains why the German measurement method is now so popular on South Korean construction sites: it is used in over 80% of the newly acquired measurement systems - a scenario no one would have expected nine years ago, when the first version of the device was awarded the bauma Innovation Award in 2016. Even back then, the two biggest advantages - repeatability and measurement speed - were already highlighted positively by the reviewers. As a fleet solution for Real-time fresh concrete moisture measurement is gaining ground on South Korean construction sitesIMKO Micromodultechnik GmbH, 76275 Ettlingen, GermanyFig. 1: Approved measurement methods on construction sites in South Korea (from left to right: microwave drying method, digitized air content meter, capacitance method, and TDR penetration method).