TrimSlab – Concrete slabs with optimized cross-section
Floor slabs account for a significant share of the total volume of materials used in building construction. Reinforced concrete flat slabs with a solid cross-section are particularly material intensive. The TrimSlab research project addressed the resulting potential for more material-efficient structural designs. For this purpose, an innovative precast concrete floor slab was designed for the same structural capacity but using 50% less material.
The element’s cross-section was optimized using an integrated design approach that considered both structural requirements and manufacturability. The slab consists of a slim top and bottom chord and thin-walled, folded webs. The web element is manufactured by concreting the individual webs and then thermoforming the reinforcement exposed between them after concrete hardening. In the next step, the concrete for the top and bottom chord is cast.
For the initial test run, impregnated carbon grid reinforcement and a C50/60 concrete with a flowable consistency and a maximum aggregate size of 8 mm were used. The specimen was 250 mm high, with chord and web thicknesses of 35 mm, and had a span of 2 m. It was loaded to failure in a three-point bending test. During the test, it exhibited favorable behavior prior to failure characterized by significant deflection and the formation of wide cracks. It ultimately failed in the tensile chord. This outcome confirmed the suitability of the cross-section and production process, demonstrating that a considerable amount of material could be saved while still reaching the envisaged structural capacity. Further elements with a 6 m span will be tested to investigate structural behavior under real-life conditions.
This research receives funding as an innovation sprint under the DATIpilot funding guideline of the Federal Ministry of Research, Technology and Space (BMFTR) under code 03DPS1073A.
