Strenghtening of Concrete Structures with Fibre Reinforced Composites

Izmed vseh konstrukcijskih materialov je beton še vedno najbolj uporabljan material. Številne betonske konstrukcije, armirane z jeklom, potrebujejo nenehno vzdrževanje, njihova preobremenitev in zanemarjanje pa pogosto vodita do korozije jekla in s tem v pospešeno razkrajanje objektov. Polimeri ojačani z vlakni ali FRP (angl. Fibre Reinforced Polymers) so material, ki se je v zadnjih desetletjih pojavil kot obetajoč alternativni material za ojačevanje betonskih konstrukcij. Namen magistrskega dela je bil preučiti FRP materiale za armiranje in zunanje ojačitve betona. Pri tem smo se osredotočili na armiranje konstrukcij s polimeri ojačanimi s steklenimi vlakni (GFRP) in možnostmi sanacije teh konstrukcij s polimeri ojačanimi z ogljikovimi vlakni (CFRP). V eksperimentalni analizi smo izdelali šest različno armiranih in ojačanih betonskih nosilcev enotnih dimenzij 10 x 15 x 90 cm. Pri tem so bili trije nosilci ojačani z jeklom, trije pa z GFRP. Določene nosilce smo strižno ojačali s CFRP in novo metodo ojačitve, t.i. NSMR (Near–Surface–Mounted Reinforcement). Rezultati analize so pokazali, da so FRP v primerjavi z jeklom veliko bolj žilav in duktilen material. Deformacija nosilcev z GFRP armaturo je bila ob porušitvi večja od nosilcev z jeklom 3–5 krat. Uporabljena strižna armatura je nosilnost vzorcev ojačanih z GFRP povečala za 120 %, v primeru jeklene armature pa za 25 %. Z NSRM ojačitvijo smo uspeli povečati nosilnost vzorcev med 10–25 %, pri tem pa se je deformacija zmanjšala med 40–60 %.Concrete is nowadays still the most commonly used construction material in the world. Numerous concrete structures, reinforced with steel, need constant maintenance and are often under the impact of corrosion that leads to accelerated destruction of the elements. Fibre reinforced polymers or FRP entered civil engineering market in past decades as an alternative material for strengthening of concrete structures. The goal of this MSc thesis is to examine FRP composites as a material suitable for reinforcement and strengthening of the structures. The focus of the thesis is on reinforcement of the structures with glass fibre reinforced polymers (GFRP) and strengthening of the structures with carbon fibre reinforced polymers (CFRP). In the experimental part of the thesis six differently strengthened concrete beams measuring 10 x 15 x 90 cm were constructed. Three beams were reinforced with steel and three with GFRP. Some beams were strengthened with shear CFRP reinforcement and some with near surface mounted CFRP reinforcement (NSMR). Results of the analysis confirmed that FRP materials have higher toughness and are more ductile compared to the steel. Deformation of the beams reinforced with GFRP exceeded deformation of the beams reinforced with steel 3–5 times. Shear strengthening of the beams improved beam strength for 120 % in case of GFRP reinforcement and for 25 % in case of steel reinforcement. NSMR strengthening increased strength of the beams for 10–25 % and at the same time decreased deformation of the beam between 40 and 60 %