Eine Plattform für die Wissenschaft: Bauingenieurwesen, Architektur und Urbanistik
Eine Plattform für die Wissenschaft: Bauingenieurwesen, Architektur und Urbanistik
Durability of an UHPFRC under mechanical and chloride loads
Highlights Long term durability of new non-proprietary UHPFRC simulating service conditions (cracking or loading) 1-year wetting–drying chloride cycles. Loading and cracking conditions promoted a higher penetration and significant chloride content. Flexural strength was not affected, stiffness might be reduced.
Abstract The high cost of UHPFRC is a limitation on the practical application in real construction projects. However, a very competitive UHPFRC approach is the hybrid structural elements, where thin layers of UHPFRC are employed to rehabilitate/strengthen damage cover concrete. New layers subjected to harsh conditions (loads and/or environmental) can eventually crack under service conditions, changing the local transport properties and thus, a faster ingress of detrimental substances occur, such as chlorides ions. Most of the studies on chloride penetration in UHPFRC have focused on determining the transport properties of sound, non-cracked specimens. Thus, an experimental campaign was carried out to assess chloride ingress in loaded and/or cracked UHPFRC and the effect of such ions on mechanical performance. Typical service cracks patterns were imposed on UHPFRC specimens and then exposed to wetting–drying cycles in a chloride solution. After 1-year chloride exposure, UHPFRC specimens were in good condition with no significant losses in flexural strength; however, stiffness might be affected. The chloride contents up to 20 mm depth were superior to the European standards critical chloride content. A minimum cover depth of 20 mm of new UHPFRC is recommended to protect a concrete substrate in hybrid structures for exposure classes XS3.
Durability of an UHPFRC under mechanical and chloride loads
Highlights Long term durability of new non-proprietary UHPFRC simulating service conditions (cracking or loading) 1-year wetting–drying chloride cycles. Loading and cracking conditions promoted a higher penetration and significant chloride content. Flexural strength was not affected, stiffness might be reduced.
Abstract The high cost of UHPFRC is a limitation on the practical application in real construction projects. However, a very competitive UHPFRC approach is the hybrid structural elements, where thin layers of UHPFRC are employed to rehabilitate/strengthen damage cover concrete. New layers subjected to harsh conditions (loads and/or environmental) can eventually crack under service conditions, changing the local transport properties and thus, a faster ingress of detrimental substances occur, such as chlorides ions. Most of the studies on chloride penetration in UHPFRC have focused on determining the transport properties of sound, non-cracked specimens. Thus, an experimental campaign was carried out to assess chloride ingress in loaded and/or cracked UHPFRC and the effect of such ions on mechanical performance. Typical service cracks patterns were imposed on UHPFRC specimens and then exposed to wetting–drying cycles in a chloride solution. After 1-year chloride exposure, UHPFRC specimens were in good condition with no significant losses in flexural strength; however, stiffness might be affected. The chloride contents up to 20 mm depth were superior to the European standards critical chloride content. A minimum cover depth of 20 mm of new UHPFRC is recommended to protect a concrete substrate in hybrid structures for exposure classes XS3.
Durability of an UHPFRC under mechanical and chloride loads
Matos, Ana Mafalda (Autor:in) / Chaves Figueiredo, Stefan (Autor:in) / Nunes, Sandra (Autor:in) / Schlangen, Erik (Autor:in) / Barroso-Aguiar, José L. (Autor:in)
07.10.2021
Aufsatz (Zeitschrift)
Elektronische Ressource
Englisch
Ca(OH)<inf>2</inf> , Calcium hydroxide , COD , Crack open displacement (µm) , COD<inf>Fmax</inf> , Crack open displacement at maximum load (µm) , COD<inf>load</inf> , Crack open displacement under load (before unloading) (µm) , COD<inf>res</inf> , Crack open displacement residual (after unloading) (µm) , C<inf>0</inf> , Initial chloride content (%) , Ccrit , Critical chloride content (%) , d , Width of the specimens (mm) , d<inf>crack</inf> , Chloride penetration depth at the maximum crack front (mm) , d<inf>f</inf> , Diameter of fibres (mm) , d<inf>m</inf> , Average chloride penetration depth in the non-cracked area (mm) , ECat , Spent equilibrium catalyst , F , Force (N/kN) , Fcr,max , Maximum Force achieved during cracking procedure (kN) , Fmax , Maximum Force (kN) , f<inf>cf</inf> , Flexural strength (MPa) , I , Span (mm) , HPC , High-performance concretes , LF , Limestone filler , l<inf>f</inf> , Length of fibres (mm) , LVDT , Linear variable differential transformer , N , Average number of cracks , NaCl , Sodium Chloride , OC , Ordinary concrete , RH , Relative humidity (%) , SCMs , Supplementary cementitious materials , SF , Silica fume , Sp , Superplasticizer , t , Time (day/hours) , UHPC , Ultra-high performance cement based composites , UHPFRC , Ultra-High-Performance Fibre Reinforced Cement based Composites , V<inf>f</inf> , Volume of fibres (%) , w/c , water to cement weight ratio , w/b , water to binder weight ratio , Ultra-high performance fibre reinforced cementitious composites (UHPFRC) , Durability , Bending , Cracked UHPFRC , Chlorides ingress
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