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Fabric reinforced cementitious mortar (FRCM), an emerging sustainable retrofit technique, has seen very limited research and applications on two-way reinforced concrete (RC) slabs. In this study, a three-dimensional finite element (FE) model is developed for FRCM-strengthened slabs, incorporating concrete nonlinearity, cracking, debonding and rupture.

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*e use of NSM FRP strengthening of concrete structures has become an attractive option to retrofit the existing structures against shear and flexure. *is paper reviews only the utilization of NSM for shear in previous review articles. A database of tests of NSM strengthened beams in shear is presented to evaluate the existing design formulations of calculating the NSM contribution in shear. *ese formulations were in agreement with the experimental results in the database. Further research topics are also identified such as the shape of NSM FRP bars, combined effects of existing steel stirrups, and NSM FRP reinforcement and analytical formulations.

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Near Surface Mounted (NSM) fiber reinforced polymer (FRP) technique with rods/strips attached at the bottom face (B-NSM) has become widely used method for retrofitting concrete structures but has several practical limitations such as accessibility problems and premature debonding. A viable alternative by attaching the NSM FRP reinforcement at the side faces (S-NSM) has recently been presented and showed excellent effectiveness in limited research studies. In this study, a robust finite element (FE) model, featuring state-of-the art modelling techniques and nonlinear properties, is developed to study the flexural behaviour of reinforced concrete (RC) beams strengthened with S-NSM FRP bars.

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Fiber reinforced cementitious mortar (FRCM) improves the performance of fiber-reinforce polymer (FRP) by replacing the organic matrix (e.g., epoxy) with inorganic one, resulting in a more sustainable alternative with a much improved fire resistance. While numerous models have been developed for FRP-confined concrete, FRCM￾confined concrete have not received nearly as much attention. This study introduces a design-oriented model for FRCM-confined concrete. The model is the first to be derived from a very large database comprising 139 experimental specimens with various geometric and material properties, complemented with additional 144 numerical specimens obtained from finite element (FE) analysis. A nonlinear three-dimensional FE model was developed and verified with experimental results. It was used to examine the effects of mortar compressive strength (fm) and thickness (tm), type of FRP fabric, number of FRCM layers (n), compressive strength of un￾confined concrete (fco), and height-to-diameter ratio (H/D). Results showed that the confined concrete strength (fcc) increases linearly as fm and tm increase, for all examined n, fco, and (H/D) values. fcc also varies almost linearly with n for all fabric types. A statistical analysis was performed on the combined database and a semi￾empirical confinement model was developed to predict the peak strength and corresponding strain. It pro￾vided much better statistical performance and correlation with results than existing models and included a special coefficient for the effects of mortar properties.

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In this research, a nonlinear 3D finite element (FE) has been developed to investigate the flexural performance of FRCM strengthened one-way reinforced concrete (RC) slabs. The concrete was simulated using a non-metal plasticity concrete model which can capture concrete cracking and crushing. Composite damage mechanics-based model was used to represent the rupture failure in the FRP textile within FRCM composite. In addition, a cohesive zone material (CZM) law is employed to model the bond-slip behaviour for the FRCM-concrete interface and predict potential debonding and slipping failures. The developed model is then validated against experimental results obtained from literature. The validation was performed by comparing the experimental results with the corresponding FE results in terms of ultimate load, deflection at steel yielding and ultimate load, load-deflection curves, and load-strain profiles. The comparison results showed that the FE model can capture the ultimate load recorded in the experiment with a difference of less than 10%. These results are motivating reasons to use the developed model in a further research to provide a comprehensive understanding of FRCM strengthened one-way slabs and conducting a detailed parametric study to characterize the effects of key design parameters.

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In this study, a robust three-dimensional finite element (FE) model has been developed for reinforced concrete beams strengthened in shear with near surface mounted (NSM) carbon fibre reinforced polymer (CFRP) rods. The FE models were developed and validated against existing experiments and presented various nonlinear constitutive material laws and interfacial relations. A detailed parametric study was performed to investigate the effects of various parameters on the performance of strengthened member. It was shown that increasing the concrete compressive strength ( ) from 20 to 50 MPa, leads to an increase in the beam’s ultimate load and contribution of NSM CFRP reinforcement. While for NSM reinforcement ratio ( ), the ultimate load slightly increased when is 0.14–0.22%, and then increased by 11% in average when increased to 0.28%. Varying the percentage of existing steel stirrups ( ) from 0.11 to 0.36%, leads to an increase in ultimate load from 8 to 15% compared to the control un-strengthened specimen. However, the further increase in (more than 0.36%) caused a reduction in the contribution of NSM CFRP technique because of the changing in the failure mode. The distance between existing steel stirrups and NSM reinforcement does not affect the behaviour. In addition, the model predictions were used to evaluate several design formulas available in the literature for this technique. It was found that some theoretical equations were conservative as long as the governing failure mode is shear.

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In this study, a non-linear three-dimensional finite element model was developed to study the impact behaviour of reinforced concrete beams strengthened in shear and/or flexure with carbon-FRP (CFRP) sheets. Concrete damage plasticity model was used for the concrete part, a traction-separation law for the CFRP-concrete inter￾face, and Hashin criteria for rupture in CFRP. Comparisons with experimental data from literature, for various properties, confirmed the accuracy of developed model. A detailed parametric analysis was performed focusing on: the impact location as a ratio (α) from support to mid-span, impact velocity (v); and several geometrical properties related to CFRP technique. Increasing α from 0.26 to 0.79 results in increasing the maximum displacement (Δmax) for both un-strengthened and strengthened beams. CFRP strengthening resulted in decreasing Δmax for different values of α and v and prevented global concrete failure for v ¼ 8.86 m/s. Δmax is also decreased by 13% when a round corner and an arched soffit were used to prepare the beam substrate for bonding the transverse sheets instead of a sharp corner. Furthermore, the paper presents detailed discussions and im￾plications for the above parameters and two additional ones, namely: configuration of transverse sheets (continuous wraps or discontinuous strips) and thickness of CFRP longitudinal sheets.

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Fiber reinforced cementitious matrix (FRCM) is emerging as a viable retrofit and confinement technique, in lieu of fiber reinforced polymer (FRP) system which suffers from a number of issues related to the use of synthetic binders. While many studies have been conducted on the use of FRCM in shear and flexural applications, few were dedicated to confinement of slender columns, particularly those related to finite element (FE) analysis. In this study, a nonlinear three-dimensional FE model has been developed to study the behavior of reinforced concrete (RC) columns confined by (FRCM) jackets, and loaded concentrically and eccentrically. Drucker-Prager (DP) concrete model, which has several improvements over traditional DP models, was used to model the concrete core. Composite failure in the fibers comprising FRCM system and column buckling were also considered in the developed FE model. The model was validated by comparing its predictions with those of three control and 8 FRCM-confined RC columns from literature. Consequently, a parametric study utilizing 96 additional models, was performed on five parameters, namely: cross￾sectional shape (square, circle, hexagon, and octagon), and for rectangular columns; aspect (h/b) ranging from 0.5 to 3, at 0.5 increment; slenderness (KL/r) ratio, considering four values, 10, 25, 50, and 75; load eccentricity (e) as a ratio (e/h) to side length (h), varying from 0 to 2.5; and concrete compressive strength (f́ c), studying three values: 20, 35, and 50 MPa. Effects of these parameters on the column’s maximum load (Pmax) and general behavior, are discussed in details in Section 6 and summarised in the conclusions part. In general, Pmax increased by 0–32% as a result of applying one layer of FRCM jacket, and showed great dependence on the examined parameters 212

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The lightweight aggregate concrete had become a wide spectrum use at civil structures nowadays. The main aim of this research is towards evaluating the efficiency of lightweight aggregate in the structural behavior of reinforced concrete slabs. A three-dimensional finite element model suitable for the analysis of lightweight concrete one-way slabs (LWC) was used through this study. This analysis has been adopted by using the finite element principles with a system computer program (ANSYS V.17.2). The ordinary reinforced concrete and LWC slabs were modeled by 8-node isoparametric brick elements, while the steel reinforcing bars were modeled as axial members (bar elements) connecting opposite nodes in the brick elements with a full interaction assumption. In the present study, some important factors were studied by using numerical model to investigate their effect on the behavior of LWC one-way slabs. The parameters that considered were: (1) Type of lightweight aggregate (crushed brick and porcelenite ); (2) Effect of different slab thickness; and (3) loading types applied. Results explained the ultimate load increasing by (17.33 %) and (60%) for crushed brick concrete when compared with normal concrete and porcelenite concrete respectively. Using crushed brick as lightweight aggregate gives more toughness than porcelenite aggregates.

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Recent increases in the amount of industrial wastes to be removed has made dealing with such waste products and gases an issue that needs to be solved with some urgency. The accelerated hardening mechanisms of light weight concrete (LWC) using carbon dioxide gas were thus studied in an experimental study to investigate the mechanical performance of concrete incorporating waste sawdust. The final results were optimised to maximise strength and minimise density using two different parameters: gas concentrations and sawdust percentages. All samples were subjected to tests of their mechanical and physical properties, including compressive strength, splitting tensile strength, water absorption, and density using the relevant standards. Parts of the samples were also submitted to thermogravimetric analysis (TGA) following the process of accelerated curing in order to quantify the consumed calcium hydroxide (Ca(OH)2) and the produced calcium carbonate (CaCO3). The results of the study showed an improvement in the physical and mechanical properties of all investigated specimens using the accelerated CO2 curing method. In addition, a 7% sawdust addition with 53% CO2 concentration resulted in higher strength in all cases. The TGA results proved that the carbonation curing resulted in lower Ca(OH)2 and higher CaCO3 content, with associated enhancement in the mechanical performance. This indicates that CO2-rich industrial emissions could find a value adding use in carbonation curing of sustainable wood-based concrete

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Nowadays, utilizationof Fibre Reinforced Polymer (FRP) in rehabilitation and strengthening of Reinforced Concrete (RC) beams is commonly used with a proper type of epoxy. Fabric Reinforced Cementitious Material (FRCM) presentsan alternative technique instead of the traditional epoxy. This paper investigates the shear performance of RC beamsusing FRCM strengthening. Finite Element method was adopted in modelingthe FRCM strengtheningfor RC beams in shear using ANSYS software with nonlinear and 3D analysis. In the beginning, the FE model was verified through comparing with the tests in the literature in terms of load-mid span deflection response, ultimate load, strain readings of reinforcement at mid-spanand the mode of failure. It was found that the FE model was capable to capture the behavior of FRCM strengthened RC beams with a high level of accuracy. This validated model has been employed later in studying some of parameters which have a potential effecton efficiency of this technique such as concrete compressive strength, number of fiber layers, and the arrangement of the fiber. Generally, it was found that the concrete compressive with high strength has significant impact in increase the efficiencyof FRCM strengthening system