An investigation is carried out into the applicability of self-compacting high-performance fiber concrete (HPFC) in foundations. A concrete mixture has been designed with a concrete cube strength of about 110 MPa. The concrete contains 60 kg/m³ steel fibers. The properties of the HPFC developed are very suitable for structural applications, especially because the post-cracking tensile strength, provided by the fibers, is higher than the axial tensile strength of the concrete so that hardening in tension occurs after crack formation, often characterized by multiple cracking. This not only results in a high bearing capacity but as well in substantial durability. As a potential application foundation elements are considered. Experiments have been carried out to determine the pre- and post-cracking strength properties, the shear resistance of short beams with loads near to the supports, the anchorage length of reinforcing bars, and the shear capacity of pile caps. The results of the tests are used for verification of the applicability of the general design rules for fiber concrete, as found in the fib Model Code 2010, to the HPFC developed. The HPFC developed is characterized by high strength and ductility, is durable and self-compacting. The research program showed that the design of structures with the HPFC considered can be based on existing design rules with some extensions.

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Traditionally industrial foundation elements are manufactured using reinforced concrete. For these elements a lot of reinforcement is necessary as these foundation elements are usually loaded by the combination of large shear forces and bending moments. Moreover, splitting and spalling reinforcement is crucial to transfer the internal stresses as very large concentrated loads are present. Due to the combination of the different reinforcement requirements the production process of these foundation elements is complex and requires a lot of time and labor. Simplification of the production process for foundation works will result in a more effective execution and de-risking of the construction schedule. Therefore, the idea was born to use self-compacting high performance fibre reinforced concrete (SCHPFRC) reinforced with traditional steel only for bending. The steel fibres will take over the functions of all other types of traditional reinforcement, i.e. shear reinforcement, transverse reinforcement, skin reinforcement, minimum reinforcement and additional reinforcement required to control crack widths. To test the capabilities and the behavior under large concentrated loads of this SCHPFRC, two extensive test series are performed at the Magnel laboratory for Concrete Research at Ghent University. The first test series consisted of the development of a mix design for the SCHSFRC, 12 CMOD tests on SCHPFRC prisms, 6 full scale loading tests on SCHPFRC beams subjected to a concentrated load to test the shear resistance and 6 full scale loading tests on SCHPFRC slabs. In the second test series additional tests are performed to confirm the findings from the first test series, to investigate the influence of the steel fibers on the anchorage length of the steel rebars and to investigate the punching resistance and the three-dimensional load-transfer of the foundation elements in more detail. Based on the outcome of the experiments the applicability of SCHPFRC is evaluated and practical design guidelines are derived.@en

Traditionally industrial foundation elements are manufactured using reinforced concrete. For these elements a lot of reinforcement is necessary as these foundation elements are usually loaded by the combination of large shear forces and bending moments. Moreover, splitting and spalling reinforcement is crucial to transfer the internal stresses as very large concentrated loads are present. Due to the combination of the different reinforcement requirements the production process of these foundation elements is complex and requires a lot of time and labor. Simplification of the production process for foundation works will result in a more effective execution and de-risking of the construction schedule. Therefore, the idea was born to use self-compacting high performance fibre reinforced concrete (SCHPFRC) reinforced with traditional steel only for bending. The steel fibres will take over the functions of all other types of traditional reinforcement, i.e. shear reinforcement, transverse reinforcement, skin reinforcement, minimum reinforcement and additional reinforcement required to control crack widths. To test the capabilities and the behavior under large concentrated loads of this SCHPFRC, two extensive test series are performed at the Magnel laboratory for Concrete Research at Ghent University. The first test series consisted of the development of a mix design for the SCHSFRC, 12 CMOD tests on SCHPFRC prisms, 6 full scale loading tests on SCHPFRC beams subjected to a concentrated load to test the shear resistance and 6 full scale loading tests on SCHPFRC slabs. In the second test series additional tests are performed to confirm the findings from the first test series, to investigate the influence of the steel fibers on the anchorage length of the steel rebars and to investigate the punching resistance and the three-dimensional load-transfer of the foundation elements in more detail. Based on the outcome of the experiments the applicability of SCHPFRC is evaluated and practical design guidelines are derived.@en