Experimental investigation of interface behaviour of RC beams strengthened with concrete layers

Strengthening of reinforced concrete beams using ultra high performance fibre reinforced concrete (UHPFRC)

“…The Initial, prior to strengthening, Beam (IB) examined in this study is based on a previous experimental program [7]. Initial Beam's cross sectional dimensions were 150 mm by 250 mm and the length was equal to 2200mm.…”

“…One of the main aims of the current study is to conduct a critical comparison of the effectiveness of this novel technique with the traditional strengthening method of using additional RC layers. For this purpose, results of a previous investigation on strengthened beams with RC layers were used [7], where roughening of concrete interface was made using an air chipping hammer, and an average roughness of 2-3 mm was achieved. There are published recommended methods to characterise and quantify concrete surface texture [49,50].…”

“…There are published recommended methods to characterise and quantify concrete surface texture [49,50]. In this study [7], Sand Patch Test was used. Dowels were not provided, since one of the aims of this study [7] was to investigate if sufficient interface performance can be provided by interface roughening without any mechanical connectors.…”

“…In this study [7], Sand Patch Test was used. Dowels were not provided, since one of the aims of this study [7] was to investigate if sufficient interface performance can be provided by interface roughening without any mechanical connectors. Also, in case of relatively 'thin' layers the use of dowels can't be easily applied since a minimum embedment length equal to six times of dowel's diameter is required [51].…”

“…There are several published experimental and theoretical studies on beams and columns strengthened with conventional concrete [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15]. A crucial parameter in this technique, which can considerably affect the durability and the performance of the strengthened structures, is the concrete shrinkage strain of the additional layers/jackets.…”