Optimizing Hemp‐lime for Sustainable and Industrial Construction: Particle Size Distribution, Sugar Content, and Raw Material Sourcing in Germany

Abstract

Hemp lime is a promising bio‐based building material, but its industrial adoption is hindered by variability in raw material quality and the absence of robust standardisation. This study characterises six hemp shive samples from different European origins (France, Germany, Poland, Turkey, and Ukraine) with respect to particle size distribution, water‐soluble sugar content, and compressive strength at 48 hours curing. Sieve analysis following DIN EN 933‐1 revealed substantial differences in gradation, ranging from the narrow mono‐modal distribution of the Turkish sample (87.6% in the 4–8 mm fraction) to the fine‐dominated profile of the Ukrainian sample (35.1% fines below 2 mm). Compressive strength varied between 0.070 and 0.155 N/mm ² , with particle size emerging as the dominant factor. Contrary to expectation, no negative correlation between sugar content and early strength was observed, attributed to the insensitivity of the NHL 2 / PROMPT binder blend to the sugar levels present. A processor‐applied sieving intervention demonstrably improved gradation consistency and mechanical reproducibility. The findings support the development of a minimum characterisation protocol for hemp shives as a basis for supplier qualification and future standardisation.