Repaired Reinforced Concrete Beams Research Articles

Experimental and analytical investigation of RC beams strengthened by ultra-high performance shotcrete

Currently, there is an increasing need for the repair of damaged structures, particularly those situated in confined and challenging locations. Historically, addressing such structures has been hampered by a lack of effective repair and rehabilitation methods. This study aims to investigate, both experimentally and analytically, the application of Ultra-High-Performance Shotcrete (UHPS) for strengthening and repairing reinforced concrete (RC) beams at the bottom. Five RC beams were cast, with one serving as a reference. The remaining four reinforced concrete beams were fabricated with grooved surfaces at the bottom. Subsequently, they underwent strengthening with UHPS at the soffit in two scenarios: one with reinforcements and one without reinforcements. The results indicate a significant enhancement in the load-carrying capacity of the composite beam, up to 126 %, when UHPS is combined with reinforcements. Additionally, the analytical method demonstrates good accuracy, with a maximum error of 16.62 % compared to the experimental results. These findings suggest that the utilization of UHPS effectively improves the structural behavior of RC beams, particularly in challenging locations. Furthermore, the proposed analytical method holds promise for practical application in the design field, offering a systematic approach for implementing UHPS and reinforcements in the repair and rehabilitation of reinforced concrete beams.

Maintenance of crack with infilling polymer modified mortar for shear deficient of reinforced concrete beam

Being a developing country, Pakistan needs sustainable and cost-effective strengthening/ retrofitting solution to be adopted/ practiced in the construction industry. The research reported in this paper was aimed to study the effectiveness of PMM, an indigenous product, for repairing reinforced concrete beams, resulting more effective and cost benefiting repair and strengthening for restoration of pre-cracked RC structures. This article presents the research results of experimental investigation conducted for repairing of cracks in shear deficient reinforced concrete (RC) beams with locally available novel material polymer modified mortar (PMM). A total of 6 beams; divided in three groups i.e. short beams, medium beams and deep beams with varying depths and same mix design were tested to four point loading under monotonic loading conditions until failure loads. Afterwards, these beams were repaired with PMM and cured with water for 72 h for retesting until failure. Load at first crack and at failure, crack pattern and deflections were recorded for all specimens during testing. Results from the experimental investigation indicate that load carrying capacity of the repaired beams was significantly restored in comparison to the control specimens. However, repaired specimens of medium group showed more improvement in load carrying capacity as compared with those of repaired specimens of short and deep group. The specimens of medium group restored up to 90% of their original load carrying capacity. The ductility is improved significantly for all shear critical repaired RC beams up to opening of cracks. Sudden brittle failure was observed after opening of repaired cracks. The contribution of PMM to load carrying capacity was found more significant for medium beams as compared to short and deep beams. The results of this study indicated that application of polymer modified mortar is effective technique for repairing of cracks in shear deficient RC beams.

Evaluating Flexural Performance of Repaired Reinforced Concrete Beams under Static and Repeated Loading Using Non-Destructive Methods.

Deterioration of concrete structures is one of the major issues faced by the construction industry. Repair and rehabilitation are necessary to extend the service life of such structures. This study aims to investigate the effect of repair material type, length of repaired region, and loading regime on the structural characteristics of the repaired reinforced concrete (RC) beams. To achieve this goal, a total of 30 repaired and non-repaired RC beams were prepared and tested under static and repeated loading conditions. Three types of sounding-based non-destructive test (NDT) methods are employed to determine the material deterioration and sub-surface delamination after repeated loading. Results showed that under static loading conditions, full-length repaired beams had better performance than 1/3-span repaired beams. Beams repaired with cementitious repair mortar containing modified binder and cementitious repair concrete in full length had a yield strength that was 14% and 9%, respectively, higher than that of beams repaired in 1/3 span. All RC beams with full-span repair outperformed the intact beams. After repeated loading, beams repaired with cementitious repair with modified binder over full length showed a 14% improvement in yield strength compared to control samples. It was found that repair materials that had a high compressive and flexural strength are beneficial. The resonant frequency drops correlate well with the yield strength results. The formulas proposed by Canadian Standards Association (CSA) 23.3 can effectively predict the moment resistance of both intact (control) and repaired RC beams. The ratio of experimental moment resistance values to its predictions ranges from 0.91 to 1.04.

Experimental and analytical investigation of using externally bonded, hybrid, fiber-reinforced polymers to repair and strengthen heated, damaged RC beams in flexure

PurposeThis study aims to conduct an experimental study and finite element model (FEM) to investigate the flexural behavior of heat-damaged beams strengthened/repaired by hybrid fiber-reinforced polymers (HFRP).Design/methodology/approachTwo groups of beams of (150 × 250 × 1,200) mm were cast, strengthened and repaired using different configurations of HFRP and tested under four-point loadings. The first group was kept at room temperature, while the second group was exposed to a temperature of 400°C.FindingsIt was found that using multiple layers of carbon fiber-reinforced polymer (CFRP) and glass fiber-reinforced polymer (GFRP) enhanced the strength more than a single layer. Also, the order of two layers of FRP showed no effect on flexural behavior of beams. Using a three-layer scheme (attaching the GFRP first and followed by two layers of CFRP) exhibited increase in ultimate load more than the scheme attached by CFRP first. Furthermore, the scheme HGC (heated beam repaired with glass and carbon, in sequence) allowed to achieve residual flexural capacity of specimen exposed to 400°C. Typical flexural failure was observed in control and heat-damaged beams, whereas the strengthened/repaired beams failed by cover separation and FRP debonding, however, specimen repaired with two layers of GFRP failed by FRP rupture. The FEM results showed good agreement with experimental results.Originality/valueFew researchers have studied the effects of HFRP on strengthening and repair of heated, damaged reinforced concrete (RC) beams. This paper investigates, both experimentally and analytically, the performance of externally strengthened and repaired RC beams, in flexure, with different FRP configurations of CFRP and GFRP.

Novel 3D printed bars for retrofitting heat damaged RC beams

Three-dimensional (3D) printing is a novel technique that has been recently used in producing printed composites for strengthening and rehabilitating complex structures. This research investigates the applicability of printed bars in strengthening and repairing unheated and heat-damaged reinforced concrete (RC) beams. The printed bars were made using Polylactic Acid (PLA) and 20% of carbon fibers. Beams were subjected to a high temperature of 700 °C for 3 h. The Near-surface mounted technique (NSM) was then adopted to strengthen the ordinary RC beams and repair the heat damaged beams using the 3D printed bars. Test results have shown that strengthening and repairing RC beams using the 3D printed bars can increase the load-carrying capacity and the initial stiffness of the beams. The 3D printed bars increased the load-carrying capacity of the heat-damaged beams up to 34%, and hence they restored their load-carrying capacity. The flexural strength was then predicted using the ACI-440 code and compared to the experimental results. The formulations proposed by the ACI-440 for calculating the flexural strength of RC beams strengthened using NSM-FRP bars are applicable but conservative in predicting the flexural strength of the beams strengthened using NSM-3D printed bars.

The repair of recycled crushed brick aggregate RC beams with shear deficiencies with CFRP

Repairing reinforced concrete (RC) beams using externally bonded carbon fibre reinforced polymer (CFRP) laminate has become one of the main rehabilitation techniques utilised to promote sustainability in construction. The aim of this study was thus to investigate the repair of rectangular simply supported reinforced crushed brick aggregate concrete beams with shear deficiencies in their design. The experimental work consisted of testing twelve full-scale beams (1400 x 200 x 150 mm) under two points load. The specimens were made of normal, and lightweight course aggregate concrete, four beam specimens were used as references, being tested until failure in shear to obtain the ultimate load carrying capacity, while the other specimens were loaded up to 60%-89.4% of the total load at failure, then repaired by wrapping in a layer of CFRP strips in two orientations (90°) and (45°). The variables investigated in this study were therefore the concrete type (normal and lightweight), shear span-to-effective depth ratio (a/d) with two variables (a/d=2.5) and (a/d=3), and the orientation of the CFRP. The results showed that a significant contribution was made by externally bonded CFRP in terms of repairing the beams, which not only refreshes initial shear capacity but also increases the ultimate capacity. The beams showed maximum reliability when the CFRP was oriented at 90° at a ratio of 72%.

Effect of web opening diameter on performance and failure mode of CFRP repaired RC beams

Abstract This paper presents an experimental assessment of the repair effectiveness of Carbon Fibre Reinforced Polymer (CFRP) laminate for damaged Reinforced Concrete (RC) beams with a circular web opening at the shear zones. The study highlights the effect of the opening diameter on CFRP repair effectiveness by examining the effect on the ultimate load capacity, deflection, steel strain, CFRP laminate strain and failure modes. In the experimental programme, a total of four beams were used inclusive of one solid beam used as a control beam. The other three beams were designed with different opening diameters and were exposed to damage at the pre-repair stage, up to their ultimate capacity. Damaged beams were repaired using externally bonded CFRP laminate around the openings. The results concluded that the CFRP laminate repair system was effective regardless of the web opening diameter. It was found that the increase in the opening diameter resulted in a higher deflection as well as higher strain values for the mid-span reinforcement and shear stirrups. The CFRP repaired beams behaviour transformed from brittle at the pre-repair stage to ductile at the post-repair stage. The failure mode of the CFRP repaired beams with a smaller opening diameter changed from shear failure to flexural failure, while the larger opening diameter beams failure mode was governed by CFRP deboning at the shear zone.

Monitoring the flexural performance of GFRP repaired corroded reinforced concrete beams using passive acoustic emission technique

AbstractThe focus of the research is to evaluate the flexural behavior and performance of glass fiber reinforced polymer (GFRP) repaired reinforced concrete (RC) beams corroded to different levels using acoustic emission (AE) techniques. A significant improvement in the flexural characteristics of the GFRP repaired corroded beams is observed with a change in failure mode from brittle to ductile. The benefits of GFRP repair in corroded RC beams are further clearly demonstrated by AE monitoring parameters of cumulative AE hits and their amplitudes. A significant improvement in the number of AE hits and the reappearance of AE cracking phases after repair of corroded beams indicate the efficiency of AE technique to monitor repaired structures also. A pictorial representation of the development of microcracks beneath the surface of concrete and GFRP to the formation of macrocracks is well demonstrated in an AE event plot. The assessment of local damage in RC beams using AE techniques subjected to simultaneous loading and corrosion and their further repair would facilitate in‐situ nondestructive evaluation of actual RC structures in future for detecting damage beneath the surface even after FRP repair.

Experimental and numerical investigation on the deflection behavior of pre-cracked and repaired reinforced concrete beams with fiber-reinforced polymer

This paper presents an experimental and numerical study on the effect of fiber-reinforced polymer (FRP) sheets/laminates on the flexural deflection of pre-cracked and repaired reinforced concrete (RC) beams. The experimental program was aimed at studying the carrying capacity of repaired beams through load-deflection curves along with failure modes which can occur in unrepaired and repaired RC beams. The types of FRP reinforcement (CFRP sheet, GFRP sheet and CFRP laminate) and the number of FRP layers were selected as two main parameters in the test program. The major code models, namely Eurocode 2, the ACI-318 and the BS-8110 are used for evaluation of ultimate moment, and the results are also compared with experiments ones. Finite element analysis (FEA) using ANSYS software is presented to predict the load-deflection behavior of the RC beams, and completed with a numerical analysis to assess the interfacial shear stresses, focusing on debonding failure. The experimental results show an improvement in the ultimate load capacity of repaired RC beams with FRP ranging from 13% to 100%, with lower mid-span deflections ranging from 15% to 35% as compared to the control beam (without FRP). On the other hand, the major code models could not accurately predict the moment capacity of RC beams strengthened with FRP sheets/laminates, with a gap closer to 1.40. Moreover, the numerical FEA predictions show a good agreement in the load-deflection response for all tested beams. Also, the numerical analysis results indicate that the shear stresses rise with the number of FRP sheets layers.

Experimental static and dynamic response of RC beams damaged and strengthened with NSM GFRP rod

Inserting FRP rods into grooves using the NSM technique has been demonstrated to be a suitable method for repairing reinforced concrete (RC) beams. There is limited experience with the use of GFRP in the strengthening of RC elements due to low Young’s modulus of glass fibers. The aim of the paper is to analyse the static and dynamic behaviour of RC beams damaged and strengthened by glass fiber reinforced polymer (GFRP) rods utilizing the near surface method (NSM). Undamaged and damaged three RC beams have been experimentally tested under bending loading with and without strengthening by GFRP rods. For a beam, damage has been represented firstly by notches on concrete cover. The beam has been successively strengthened by epoxy resin and NSM GFRP rod and then subjected to bending tests. Vibration tests have been adopted as nondestructive method of control during the experiments to assess the response of RC beams at different damage steps of concrete or due to decrease of bond of GFRP rod. Vibration tests foresaw two boundary conditions, respectively, free-free and hinged ends. Experimental static and vibration results are below shown; discussion and comments on the strengthening bond of NSM GFRP rod have been developed.

A new anchorage system for CFRP strips in externally strengthened RC continuous beams

Attaching fiber-reinforced polymer (FRP) strips externally on the surface is a beneficial strategy for retrofitting and repairing reinforced concrete (RC) beams subjected to flexural loading. Despite widespread usage of continuous RC beams, research addressing their performance when reinforced externally with FRP strips is scarce. The loading capacity, moment redistribution capacity, and ductility of FRP strip-reinforced RC members are lower than those of RC beams without FRP strips, due to debonding failures. To avoid early failure in an RC beam reinforced with FRP strips, various anchorage techniques have been proposed. An experimental study was carried out in this research to investigate the flexural performance and moment redistribution capacity of continuous (two-span) RC beams reinforced with carbon fiber-reinforced polymer (CFRP) strips. To avoid untimely failure and improve load-carrying and moment redistribution capacity, as well as ductility, an end anchorage mechanism was proposed. Here, four 6000-mm continuous beams with 250 × 150-mm sections were constructed. The obtained results indicated that utilizing the proposed anchor for the CFRP strips in the continuous beams led to a considerable increase in the loading capacity, moment redistribution ratio, and ductility in comparison with the CFRP-reinforced beams without the anchor. Furthermore, for predicting the load-bearing capacity of a continuous RC beam reinforced using CFRP strips, an analytical model was put forward, whose results showed proper agreement with the test results.

Flexural experiment and capacity investigation of CFRP repaired RC beams under heavy pre-damaged level

This paper presents an experimental study to determine the effectiveness of carbon fiber reinforced polymer (CFRP) sheets as a flexural repair system for reinforced concrete (RC) beams.One reference beam and nine CFRP repaired RC beams under heavy pre-damaged level are designed and tested in this study. The effects of several parameters including pre-damaged level, CFRP sheet layer and reinforcement ratio on failure mode, flexural deflection, moment-curvature relation and stress-strain behavior of CFRP sheet are investigated. In the first scenario, a reference beam is tested to determine load levels that can be used as pre-damaged for the tests. With respect to the second experiment, the test beam is subjected to a pre-damaged load equivalent to 40% or 80% of the yield load of the reference beam, respectively. Two failure modes such as the debonding failure of CFRP sheet and the fracture failure of CFRP sheet are found for the strengthened RC beams. The flexural bearing capacity of strengthened RC beams increases as the CFRP sheet layer or reinforcement ratio increases, while it decreases with the pre-damaged level increases. The decrease of pre-damaged level or the improvement of CFRP sheet layer or reinforcement ratio will decrease the deflection of CFRP repaired RC beams. Considering the effect of pre-damaged level and strengthening layer of CFRP sheet, a reduction coefficient of the CFRP sheet layer and an effect coefficient of pre-damaged level are introduced and then a formula for predicting the flexural capacity of CFRP repaired RC beams under heavy pre-damaged level is proposed and it agrees well with the test data.

An experimental study on flexural strengthening of RC beams using CFRP sheets

The use of carbon fiber reinforced polymer (CFRP) sheets is becoming a widely accepted solution for strengthening and repairing rein-forced concrete (RC) structures. To date, the behavior of RC beams, strengthened with 60˚ and 45˚ inclined CFRP sheets, has not clearly explained. An experimental program is proposed in this paper to investigate the flexural behavior of RC beams strengthened with CFRP sheets. CFRP sheets were epoxy bonded to the tension face to enhance the flexural strength of beams inducing different orientation angles of 0˚, 45˚, 60˚ and 90˚ with the beam longitudinal axis. The study shows that strengthening RC beams with CFRP sheets is highly influenced by the orientation angle of the sheets. The orientation angle plays a key role in changing the crack pattern and hence the failure mode. The influence of CFRP sheets was adequate on increasing the flexural strength of RC beams but the ductility of the beams was reduced. The best performance was obtained when strengthening RC beam obliquely using 45˚ inclined CFRP sheets where the specimen experienced additional deflection and strength of 56% and 12% respectively and the reduction in its ductility was the least. It is recom-mended to strengthen RC beams, which are weak in flexure, using 45˚ inclined CFRP sheets.

Ductility and Toughness of Unsymmetrical CFRP Strengthening of Reinforced Concrete Beams

The use of externally bonded composite materials such as carbon fiber reinforced polymers (CFRP) sheets is a modern and convenient way for strengthening and repairing reinforced concrete (RC) beams. This study presents experimental investigations on the flexural behavior of reinforced concrete beams strengthened by unsymmetrical CFRP sheets with various configurations. Effects of number of which strengthened faces of strengthening and fiber direction on the flexural strength of RC beams are examined. Six RC beams with dimensions of 100 mm * 220 mm were casted and tested under two points loading. One beam considered as a reference (unstrengthened) beam. Five residual beams were strengthened using CFRP sheets with various configurations. From the results, it was observed that all strengthened beams showed higher ultimate load capacity than that of the control beam. On the other hand, it was found that a progressive reduction in flexural ductility and toughness of beams with strengthening in one face and two faces with horizontal fiber direction. The highest decrease in flexural ductility and toughness for strengthened beams with horizontal fiber direction in comparison to control beam were 63% and 54%, respectively. On the contrary, the flexural ductility and toughness of strengthened beams increased with strengthening by vertical fiber direction. Additionally, the maximum percentage of increase in flexural ductility and toughness were 41% and 54%, respectively in comparison with control beam.

Flexural behaviour of RC beams strengthened with near-surface-mounted BFRP bars

Basalt-fibre-reinforced polymers (BFRPs) are promising economical materials developed in recent years for strengthening or repairing reinforced concrete (RC) structures. The effectiveness of strengthening RC beams with near-surface-mounted (NSM) BFRP reinforcement was investigated in this study. One reference beam and six beams strengthened with NSM BFRP reinforcements were tested under four-point loading. The main test variables were the NSM reinforcement ratio, the tensile reinforcement ratio and the pre-cracking load. The experimental results indicated that, compared with the control beam, both the load-carrying capacity and flexural stiffness of the strengthened concrete beams increased due to use of NSM BFRP bars. For the NSM-strengthened concrete beams, the pre-cracked specimens failed by BFRP bar end cover separation while the directly strengthened specimens (not pre-loaded) were governed by concrete crushing. Analytical models based on the section analysis method were developed to predict the maximum bending moment and ultimate deflection at mid-span of the concrete beams strengthened with NSM BFRP bars. The analytical values of maximum bending moment and ultimate mid-span deflection were in good agreement with the experimental results.

An Advanced Method for Repairing Severely Damaged Beams in Shear with Externally Bonded Steel Plates Using Adhesive and Steel Connectors

Repairing and strengthening of damaged reinforced concrete (RC) beams using externally bonded (EB) steel plates has gained universal acceptance. The disadvantage of this method, however, is the premature debonding of the externally bonded strip, which is brittle and an undesired mode of failure. It is also known that the debonding failure of EB steel plates prevents the RC beam from reaching its full strengthening capacity. This study aims to increase the scientific understanding of the behaviour of fully damaged RC beams strengthened/retrofitted in shear by means of EB steel plates. It also concentrates on preventing or delaying premature debonding of the adhesively bonded steel plates using new embedded adhesive and steel connectors. To achieve these objectives, seven beams with a deficient shear design were loaded monotonically up to maximum load capacities and repaired using the proposed connectors. One beam was used as a reference beam; the other six damaged beams were repaired with vertical and inclined steel plates. The presence/absence of the new embedded connectors was investigated with these two types of configurations. Theoretical models were also proposed to predict the effective debonding strain and the shear capacities of beam specimens. A comparison among these beams was done to investigate the efficiency of these connectors to enhance the bond strength between the externally bonded steel plates and the concrete surface on the web sides of the repaired RC beams. It is concluded that using steel and adhesive connectors to fix EB steel plates for repairing severely shear-damaged RC beams can delay the premature debonding failure and restore the original shear capacity of the these beams. Finally, the proposed model was satisfactorily verified through the experimental investigations and with the current design guidelines.

Crack damage mitigation and shear behavior of shear-dominant reinforced concrete beams repaired with strain-hardening cement-based composite

This research aims to study: (1) the crack damage mitigation and shear behavior of reinforced concrete (RC) beams that have been repaired using strain-hardening cement-based composite (SHCC) via experimental testing and (2) the contribution of the SHCC layers to the shear strength of the repaired RC beams via predictions. Five cantilever RC beams with a shear span-to-depth ratio of 2.8 were subjected to cyclic concentrated loading. The study variables include two types of tensile performance of the SHCC (with low or high strength in tension) and two repair methods (patching and layering). The experimental results show that the use of a SHCC layer leads to a substantial increase in the shear strength and ductility of the RC beams after the peak load. During the tests, all of the SHCC repaired beams showed delamination along the interface between the concrete and SHCC, and the shear resistance started to drop. However, the results also indicate that SHCC layers can be effective repair material for enhancing the control of cracking to help protect the concrete from the migration of aggressive agents in severe environments. In order to predict the shear strength of RC beams that have been repaired with SHCC, two methods were used in this study; one is based on Dinh's proposed model that considers the shear strength in both the compression and tension zones, and the other method considers the shear strength of the reinforcement, such as a stirrup or fiber-reinforced polymer (FRP) laminate that considers only the tensile strength across cracks. These two methods were able to predict the contribution of the SHCC layer to the shear strength of the RC beams, and the predicted shear strength values were very similar between the two methods.

A new fire resistant FRP for externally bonded concrete repair

Fiber reinforced polymer (FRP) composites, as a mature technology, have been widely used to repair/retrofit/reinforce damaged/degraded concrete structures such as steel reinforced concrete (RC) beams or columns by externally bonding FRP sheet(s) onto the surface of substrate concrete structures. However, the performance of FRP systems exposed to fire is a serious concern due to the combustibility of FRPs. The objective of this study is to understand and develop a new fire resistant technology with nanoclay reinforced intumescent coating. RC beams were prepared, damaged, and repaired by FRP with the new coating. The repaired RC beams were subjected to fire hazard again, and re-evaluated for its residual structural capacity. The effectiveness of the developed new coating for fire resistance was evaluated based on the test results. It is believed that this coating system would enhance fire resistance of the FRP, and safety and reliability of FRP repaired concrete structures.

Assessment of effectiveness of CFRP repaired RC beams under different damage levels based on flexural stiffness

This paper presents a study to determine the effectiveness of Carbon Fiber Reinforced Polymer (CFRP) sheets as a flexural repair system for Reinforced Concrete (RC) beams. The effectiveness of these sheets is ascertained by monitoring the flexural stiffness recovery. Experimental work is conducted on scaled beams where four beams are used as the datum. The first beam is without CFRP sheets, the second is a repaired beam after pre-damaged under design load limit, whilst the third is a repaired beam after pre-damaged under steel yield load limit, and the fourth is a repaired beam after pre-damaged under ultimate load. Comparisons are made based on the flexural stiffness recovery, crack patterns, load capacity, and failure modes of the beams. The study validates the ability of the flexural stiffness change in order to monitor the effect of the damage as well as the effectiveness of the repair on stiffness recovery. The results prove the effectiveness of the CFRP sheets as a repair technique which increases the flexural stiffness and the ultimate load capacity whatever the pre-repair damage levels. In addition, this study indicates the ability of re-repairing the beams in the case of CFRP debonding. The failure modes are controlled by the pre-repair damage flexural crack wherein it causes the CFRP debonding.

Assessment of adhesive setting time in reinforced concrete beams strengthened with carbon fibre reinforced polymer laminates

The strengthened effectiveness and the performance capacity of repaired Reinforced Concrete (RC) structures with Carbon Fibre Reinforced Polymer (CFRP) sheets is dependent on the properties of the adhesive interface layer. Adhesive material requires a specific setting time to achieve the maximum design capacity. Adhesive producer provides technical data which demonstrates the increase with time of the capacity, up to the maximum. The aim of this study is to investigate the effect of the adhesive setting time on the modal parameters as an indication of the effectiveness of CFRP on repaired RC beams. Firstly, datum modal parameters were determined on the undamaged beam and subsequently the parameters were obtained when damaged was induced on the RC beam by application of load until the appearance of the first crack. Finally, the RC beam is repaired with externally bonded CFRP sheets, and modal parameters are once again applied after 0.5, 1, 2, 3, 5, 8, 11, 15 and 18days. The comparison is made with the data based on half day results in order to monitor the change in the modal parameters corresponding to the adhesive setting time. The modal parameters where used as indicators for the effectiveness of CFRP are affected by the adhesive time as shown in this study. Results are compared with the adhesive technical data provided by the adhesive producer.