Title Participants Abstract "Development and experimental validation of a lightweight Stay-in-Place composite formwork for concrete beams." "Sven De Sutter, Olivier Remy, Tine Tysmans, Jan Wastiels" "Context: Current formwork research aims towards new cost-competitive formwork systems and materials that focus on labour reduction and efficient material use. This labour cost is reduced when using Stay-in-Place (SiP) formworks. Besides its forming function, SiP formwork can moreover have a protective, an aesthetic or even a structural contribution to the hardened concrete element. Objective: Using cement composites, the authors developed a new Stay-in-Place formwork concept for beams that is lightweight, easy to place and omits steel reinforcement. Method: This paper describes the conceptual design, the analytical modelling of the loadbearing behaviour and the bending tests that demonstrate its structural feasibility. Results: Unlike for steel-reinforced concrete beams, serviceability limit state becomes dominant for the developed hybrid beams. As experiments show, hybrid beams with equal stiffness as traditional reinforced concrete beams, have an increased load bearing capacity of 87%, while being 28% lighter. Conclusion: This paper proves the feasibility and potential of structural SiP formworks in cement composites with hollow core elements for future structural applications." "Stay-in-Place Formwork of TRC Designed as Shear Reinforcement for Concrete Beams" "Svetlana Verbruggen, Olivier Remy, Jan Wastiels" "In order to reduce on-site building time, the construction industry shows an increasing interest in stay-in-place formwork with a reinforcement function after concrete hardening, such as CFRP formwork confinement for columns. The current combined systems however do not answer the demand of the building industry for a material system that is both lightweight and fire safe. High performance textile reinforced cement (TRC) composites can address this need.They can be particularly interesting for the shear reinforcement of concrete beams.This paper describes a preliminary analysis and feasibility study on structural stay-in-place formwork made of TRC. Comparative bending experiments demonstrate that a fully steel reinforced beamand an equivalent beam with shear reinforcement in TRC formwork show similar yielding behaviour, indicating that the TRC shear reinforcement system actually works. Moreover, the cracking moment of the concrete was more or less doubled, resulting in a much lower deflection in serviceability limit state than calculated. Digital image correlation measurements show that the latter is due to the crack bridging capacity of the external TRC shear reinforcement." "Structural stay-in-place formwork of textile reinforced cement for concrete beams" "Svetlana Verbruggen, Olivier Remy, Jan Wastiels" "A preliminary analysis and feasibility study is performed of structural stay-in-place formwork made of glass fibre reinforced inorganic phosphate cement (IPC). High fibre contents (20% in volume and more), which can be obtained with fibre mats, allow for thin lightweight formworks, which can (partially) replace the bending and shear reinforcement of concrete beams. As a comparison, a fully steel reinforced beam, a fully glass fibre reinforced IPC supported beam, and a combined beam with longitudinal steel reinforcement and glass fibre reinforced IPC formwork as shear reinforcement are designed. The calculation shows that the amount of glass fibre reinforced IPC necessary to meet the deflection constraints in the serviceability limit state is approximately the double of the amount needed in the ultimate limit state. Bending experiments, performed on beams of 2,30 m span, show that when buckling of the thin walled structural formwork is prevented, the beams show a yielding behaviour similar to the one of standard steel reinforced beams. An important observation during these tests was that the cracking moment of the concrete was more or less doubled, which resulted in a much lower deflection than calculated. This means that the section of glass fibre reinforced IPC calculated to meet the ultimate limit state would be sufficient for the serviceability limit state as well." "Drying shrinkage and swelling of 3D printed concrete stay-in-place formwork" "Michiel Bekaert, Kim Van Tittelboom, Geert De Schutter" "Concrete additive manufacturing can be used in many applications. One of them is to create stay-in-place formwork. The automatic production process is ideal to quickly produce complex elements. Alt-hough the idea is straight forward, some facets are still open questions. One of them is the behaviour of printed concrete as formwork material during and after pouring conventional concrete into the form-work. In this experimental study, the effect of drying shrinkage and swelling of the printed elements during casting was investigated. Shrinkage and swelling tests were performed on 3D printed linear formwork material over several days. The elements were fully submerged in the water to simulate the exposure to fresh cast concrete. Results show that 46-61% of the drying shrinkage of the material is recovered after 24 hours of submersion. Consequently, one-sided moistening of the formwork can lead to warping" "Structural stay-in-place formwork in textile reinforced cement composites for very slender concrete columns" "Evy Verwimp, Olivier Remy, Jan Wastiels" "The increasing interest in the architectural design of columns demands for new formwork and reinforcement techniques. This paper studies the use of textile reinforced cement (TRC) composites as a material for structural stay-in-place formwork of concrete columns. In wet phase, this composite shows similar advantages to fabric formwork for manufacturing freely shaped columns. Hardening at ambient temperatures, the TRC composite formwork allows for facilitated manufacturing of a priori fixed shapes. The TRC composite stay-in-place formwork can moreover replace the steel reinforcement of concrete columns. Eliminating the steel reinforcement, no concrete corrosion cover is required and very slender columns can be designed. This paper evaluates the structural as well as architectural potential of stay-in-place TRC formwork for the design of very slender concrete columns. The influence of the structural formwork on the loadbearing behaviour of circular concrete columns is studied. A design exercise, using these columns in a building structure, illustrates the new architectural design possibilities this stay-in-place formwork technique brings." "3D printed concrete as stay‐in‐place formwork : mechanics during casting and curing" "Michiel Bekaert, Kim Van Tittelboom, Geert De Schutter" "Research in 3D concrete printing has gained an exponential increase in attention over the last decades. The automated production process can be beneficial to reduce material use and increase form freedom of produced elements. Disadvantages are the difficulty to apply reinforcement, the speed of execution if massive elements have to be made and the uncertain durability performance of the printed material. These aspects still lead to reticence in the concrete construction industry to use 3D printing at a large scale. To lower the threshold to move from the conventional toward the new construction technique, a combination of 3D printed and conventional concrete is proposed namely concrete elements with stay-in-place 3D printed formwork. In this paper, experimental research has been performed to investigate the behavior of 3D printed formwork during casting and curing of fresh material. Cylindrical formwork was printed on small scale and filled with self-compacting concrete. During the experiments, strain development and temperature evolution were measured in and around the elements. The obtained data was analyzed taking in attention the material characteristics of both materials in order to separate the different mechanisms. Results showed that the formwork is subjected to the lateral pressure of the cast concrete, moisture warping and thermal curling. The strains in the formwork increase significantly after casting as a result of moisture warping and thermal curling. The peak strain of the concrete element is reached during the hydration phase of the cast concrete. As the cast concrete stiffened in a slightly deformed formwork, residual strains will be present after the element cooled down." "Quality of the bond between a Strain Hardening Cement Composite stay-in-place formwork and concrete: Comparison of two experimental set-ups" "Maciej Wozniak, Tine Tysmans, Svetlana Verbruggen, Johnny Vantomme" "Numerical evaluation of structural stay-in-place formwork in textile reinforced cement composite for concrete shells" "Evy Verwimp, Tine Tysmans, Marijke Mollaert" "Cement composite stay-in-place formwork: A concept for future building systems." "Olivier Remy, Svetlana Verbruggen, Jan Wastiels" "The use of a recently developed inorganic phosphate cement with grain sizes less than 100 micrometer in combination with an adapted manufacturing process creates the possibility to obtain cement composites with a never been seen fiber volume ratio (Vf) of up to 25-30%, a factor 2 to 10 times higher than conventional cement composites. The forthcoming gain in tensile strength enables the material to be used in high performance building applications such as sandwich panels, structural claddings and concrete repair. This paper presents a concept for a lightweight stay-in-place cement composite formwork taking advantage of this new promising material. Full scale tests analyzing the structural behavior indicate the opportunities of this innovative forming technique. Results also show an improved mechanical behavior of the composite (concrete-formwork) beam as the micro cracking phenomenon of concrete in tension is better controlled and crack propagation is delayed compared to a traditional steel reinforced concrete beam." "Reinforcing concrete shells with cement composite stay-in-place formwork: Numerical analysis of a case study." "Evy Verwimp" "This paper describes a new method to construct concrete shells using textile reinforced cement (TRC) composites as flexible formwork and tensile reinforcement. By means of a case study on a synclastic concrete shell, which is a compression-only structure under its self weight, the paper presents the analysis of the TRC formwork on the one hand and the TRC reinforcement on the other hand. The analysis of the formwork and the reinforcement is performed using the nite element software Abaqus. For this synclastic shell, the formwork stage is the deciding stage. Local buckling of the edges of the shell's formwork is the determining factor for the TRC thickness. For this reason, special attention is paid to these edges and to solutions which decrease the needed TRC thickness."